Cache redesign part 1, and add support for alternative links

.github/workflows/build.yml

@@ -65,6 +65,13 @@ jobs:
       - name: Run specs (unit tests)
         run: yarn run test:headless
 
+      # NOTE: Angular CLI only supports code coverage for specs. See https://github.com/angular/angular-cli/issues/6286
+      # Upload coverage reports to Codecov (for Node v12 only)
+      # https://github.com/codecov/codecov-action
+      - name: Upload coverage to Codecov.io
+        uses: codecov/codecov-action@v1
+        if: matrix.node-version == '12.x'
+
       # Using docker-compose start backend using CI configuration
       # and load assetstore from a cached copy
       - name: Start DSpace REST Backend via Docker (for e2e tests)
@@ -78,10 +85,3 @@ jobs:
 
       - name: Shutdown Docker containers
         run: docker-compose -f ./docker/docker-compose-ci.yml down
-
-      # NOTE: Angular CLI only supports code coverage for specs. See https://github.com/angular/angular-cli/issues/6286
-      # Upload coverage reports to Codecov (for Node v12 only)
-      # https://github.com/codecov/codecov-action
-      - name: Upload coverage to Codecov.io
-        uses: codecov/codecov-action@v1
-        if: matrix.node-version == '12.x'

angular.json

@@ -94,6 +94,12 @@
             "polyfills": "src/polyfills.ts",
             "tsConfig": "tsconfig.spec.json",
             "karmaConfig": "karma.conf.js",
+            "sourceMap": {
+              "scripts": false,
+              "styles": false,
+              "hidden": false,
+              "vendor": false
+            },
             "assets": [
               "src/assets"
             ],

src/app/+admin/admin-access-control/epeople-registry/epeople-registry.component.spec.ts

@@ -8,7 +8,7 @@ import { BrowserModule, By } from '@angular/platform-browser';
 import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateLoader, TranslateModule, TranslateService } from '@ngx-translate/core';
 import { Observable } from 'rxjs/internal/Observable';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../core/data/remote-data';
 import { FindListOptions } from '../../../core/data/request.models';
 import { EPersonDataService } from '../../../core/eperson/eperson-data.service';
@@ -44,7 +44,7 @@ describe('EPeopleRegistryComponent', () => {
       activeEPerson: null,
       allEpeople: mockEPeople,
       getEPeople(): Observable<RemoteData<PaginatedList<EPerson>>> {
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: this.allEpeople.length, totalElements: this.allEpeople.length, totalPages: 1, currentPage: 1 }), this.allEpeople));
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: this.allEpeople.length, totalElements: this.allEpeople.length, totalPages: 1, currentPage: 1 }), this.allEpeople));
       },
       getActiveEPerson(): Observable<EPerson> {
         return observableOf(this.activeEPerson);
@@ -54,18 +54,18 @@ describe('EPeopleRegistryComponent', () => {
           const result = this.allEpeople.find((ePerson: EPerson) => {
             return ePerson.email === query
           });
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: [result].length, totalElements: [result].length, totalPages: 1, currentPage: 1 }), [result]));
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: [result].length, totalElements: [result].length, totalPages: 1, currentPage: 1 }), [result]));
         }
         if (scope === 'metadata') {
           if (query === '') {
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: this.allEpeople.length, totalElements: this.allEpeople.length, totalPages: 1, currentPage: 1 }), this.allEpeople));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: this.allEpeople.length, totalElements: this.allEpeople.length, totalPages: 1, currentPage: 1 }), this.allEpeople));
           }
           const result = this.allEpeople.find((ePerson: EPerson) => {
             return (ePerson.name.includes(query) || ePerson.email.includes(query))
           });
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: [result].length, totalElements: [result].length, totalPages: 1, currentPage: 1 }), [result]));
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: [result].length, totalElements: [result].length, totalPages: 1, currentPage: 1 }), [result]));
         }
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: this.allEpeople.length, totalElements: this.allEpeople.length, totalPages: 1, currentPage: 1 }), this.allEpeople));
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: this.allEpeople.length, totalElements: this.allEpeople.length, totalPages: 1, currentPage: 1 }), this.allEpeople));
       },
       deleteEPerson(ePerson: EPerson): Observable<boolean> {
         this.allEpeople = this.allEpeople.filter((ePerson2: EPerson) => {

src/app/+admin/admin-access-control/epeople-registry/epeople-registry.component.ts

@@ -5,7 +5,7 @@ import { TranslateService } from '@ngx-translate/core';
 import { BehaviorSubject, combineLatest, Observable } from 'rxjs';
 import { Subscription } from 'rxjs/internal/Subscription';
 import { map, switchMap, take } from 'rxjs/operators';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../core/data/remote-data';
 import { EPersonDataService } from '../../../core/eperson/eperson-data.service';
 import { EPerson } from '../../../core/eperson/models/eperson.model';
@@ -15,13 +15,16 @@ import { PaginationComponentOptions } from '../../../shared/pagination/paginatio
 import { EpersonDtoModel } from '../../../core/eperson/models/eperson-dto.model';
 import { FeatureID } from '../../../core/data/feature-authorization/feature-id';
 import { AuthorizationDataService } from '../../../core/data/feature-authorization/authorization-data.service';
-import { getAllSucceededRemoteDataPayload } from '../../../core/shared/operators';
-import { ErrorResponse, RestResponse } from '../../../core/cache/response.models';
+import {
+  getAllSucceededRemoteDataPayload,
+  getFirstCompletedRemoteData
+} from '../../../core/shared/operators';
 import { ConfirmationModalComponent } from '../../../shared/confirmation-modal/confirmation-modal.component';
 import { NgbModal } from '@ng-bootstrap/ng-bootstrap';
 import { RequestService } from '../../../core/data/request.service';
 import { filter } from 'rxjs/internal/operators/filter';
 import { PageInfo } from '../../../core/shared/page-info.model';
+import { NoContent } from '../../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-epeople-registry',
@@ -159,7 +162,7 @@ export class EPeopleRegistryComponent implements OnInit, OnDestroy {
                       })
                   );
           })).pipe(map((dtos: EpersonDtoModel[]) => {
-              return new PaginatedList(epeople.pageInfo, dtos);
+              return buildPaginatedList(epeople.pageInfo, dtos);
           }))
         })).subscribe((value) => {
           this.ePeopleDto$.next(value);
@@ -215,13 +218,12 @@ export class EPeopleRegistryComponent implements OnInit, OnDestroy {
       modalRef.componentInstance.response.pipe(take(1)).subscribe((confirm: boolean) => {
         if (confirm) {
           if (hasValue(ePerson.id)) {
-            this.epersonService.deleteEPerson(ePerson).pipe(take(1)).subscribe((restResponse: RestResponse) => {
-              if (restResponse.isSuccessful) {
+            this.epersonService.deleteEPerson(ePerson).pipe(getFirstCompletedRemoteData()).subscribe((restResponse: RemoteData<NoContent>) => {
+              if (restResponse.hasSucceeded) {
                 this.notificationsService.success(this.translateService.get(this.labelPrefix + 'notification.deleted.success', { name: ePerson.name }));
                 this.reset();
               } else {
-                const errorResponse = restResponse as ErrorResponse;
-                this.notificationsService.error('Error occured when trying to delete EPerson with id: ' + ePerson.id + ' with code: ' + errorResponse.statusCode + ' and message: ' + errorResponse.errorMessage);
+                this.notificationsService.error('Error occured when trying to delete EPerson with id: ' + ePerson.id + ' with code: ' + restResponse.statusCode + ' and message: ' + restResponse.errorMessage);
               }
             })
           }}

src/app/+admin/admin-access-control/epeople-registry/eperson-form/eperson-form.component.spec.ts

@@ -1,14 +1,13 @@
 import { of as observableOf } from 'rxjs';
 import { CommonModule } from '@angular/common';
 import { NO_ERRORS_SCHEMA } from '@angular/core';
-import { async, ComponentFixture, inject, TestBed } from '@angular/core/testing';
+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { FormsModule, ReactiveFormsModule } from '@angular/forms';
 import { BrowserModule, By } from '@angular/platform-browser';
 import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateLoader, TranslateModule } from '@ngx-translate/core';
 import { Observable } from 'rxjs/internal/Observable';
-import { RestResponse } from '../../../../core/cache/response.models';
-import { PaginatedList } from '../../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../core/data/remote-data';
 import { FindListOptions } from '../../../../core/data/request.models';
 import { EPersonDataService } from '../../../../core/eperson/eperson-data.service';
@@ -46,7 +45,7 @@ describe('EPersonFormComponent', () => {
       activeEPerson: null,
       allEpeople: mockEPeople,
       getEPeople(): Observable<RemoteData<PaginatedList<EPerson>>> {
-        return createSuccessfulRemoteDataObject$(new PaginatedList(null, this.allEpeople));
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(null, this.allEpeople));
       },
       getActiveEPerson(): Observable<EPerson> {
         return observableOf(this.activeEPerson);
@@ -56,18 +55,18 @@ describe('EPersonFormComponent', () => {
           const result = this.allEpeople.find((ePerson: EPerson) => {
             return ePerson.email === query
           });
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), [result]));
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), [result]));
         }
         if (scope === 'metadata') {
           if (query === '') {
-            return createSuccessfulRemoteDataObject$(new PaginatedList(null, this.allEpeople));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(null, this.allEpeople));
           }
           const result = this.allEpeople.find((ePerson: EPerson) => {
             return (ePerson.name.includes(query) || ePerson.email.includes(query))
           });
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), [result]));
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), [result]));
         }
-        return createSuccessfulRemoteDataObject$(new PaginatedList(null, this.allEpeople));
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(null, this.allEpeople));
       },
       deleteEPerson(ePerson: EPerson): Observable<boolean> {
         this.allEpeople = this.allEpeople.filter((ePerson2: EPerson) => {
@@ -75,8 +74,9 @@ describe('EPersonFormComponent', () => {
         });
         return observableOf(true);
       },
-      create(ePerson: EPerson) {
-        this.allEpeople = [...this.allEpeople, ePerson]
+      create(ePerson: EPerson): Observable<RemoteData<EPerson>> {
+        this.allEpeople = [...this.allEpeople, ePerson];
+        return createSuccessfulRemoteDataObject$(ePerson);
       },
       editEPerson(ePerson: EPerson) {
         this.activeEPerson = ePerson;
@@ -87,18 +87,13 @@ describe('EPersonFormComponent', () => {
       clearEPersonRequests(): void {
         // empty
       },
-      tryToCreate(ePerson: EPerson): Observable<RestResponse> {
-        this.allEpeople = [...this.allEpeople, ePerson]
-        return observableOf(new RestResponse(true, 200, 'Success'));
-      },
-      updateEPerson(ePerson: EPerson): Observable<RestResponse> {
+      updateEPerson(ePerson: EPerson): Observable<RemoteData<EPerson>> {
         this.allEpeople.forEach((ePersonInList: EPerson, i: number) => {
           if (ePersonInList.id === ePerson.id) {
             this.allEpeople[i] = ePerson;
           }
         });
-        return observableOf(new RestResponse(true, 200, 'Success'));
-
+        return createSuccessfulRemoteDataObject$(ePerson);
       }
     };
     builderService = getMockFormBuilderService();
@@ -299,7 +294,7 @@ describe('EPersonFormComponent', () => {
 
     it ('should call the epersonFormComponent delete when clicked on the button' , () => {
       spyOn(component, 'delete').and.stub();
-      spyOn(component.epersonService, 'deleteEPerson').and.returnValue(observableOf(new RestResponse(true, 204, 'No Content')));
+      spyOn(component.epersonService, 'deleteEPerson').and.returnValue(createSuccessfulRemoteDataObject$('No Content', 204));
       const deleteButton = fixture.debugElement.query(By.css('.delete-button'));
       deleteButton.triggerEventHandler('click', null);
       expect(component.delete).toHaveBeenCalled();
@@ -307,7 +302,7 @@ describe('EPersonFormComponent', () => {
 
     it ('should call the epersonService delete when clicked on the button' , () => {
       // ePersonDataServiceStub.activeEPerson = eperson;
-      spyOn(component.epersonService, 'deleteEPerson').and.returnValue(observableOf(new RestResponse(true, 204, 'No Content')));
+      spyOn(component.epersonService, 'deleteEPerson').and.returnValue(createSuccessfulRemoteDataObject$('No Content', 204));
       const deleteButton = fixture.debugElement.query(By.css('.delete-button'));
       expect(deleteButton.nativeElement.disabled).toBe(false);
       deleteButton.triggerEventHandler('click', null);

src/app/+admin/admin-access-control/epeople-registry/eperson-form/eperson-form.component.ts

@@ -10,14 +10,17 @@ import { TranslateService } from '@ngx-translate/core';
 import { Subscription, combineLatest, of } from 'rxjs';
 import { Observable } from 'rxjs/internal/Observable';
 import { switchMap, take } from 'rxjs/operators';
-import { RestResponse } from '../../../../core/cache/response.models';
-import { PaginatedList } from '../../../../core/data/paginated-list';
+import { PaginatedList } from '../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../core/data/remote-data';
 import { EPersonDataService } from '../../../../core/eperson/eperson-data.service';
 import { GroupDataService } from '../../../../core/eperson/group-data.service';
 import { EPerson } from '../../../../core/eperson/models/eperson.model';
 import { Group } from '../../../../core/eperson/models/group.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../../core/shared/operators';
+import {
+  getRemoteDataPayload,
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
+} from '../../../../core/shared/operators';
 import { hasValue } from '../../../../shared/empty.util';
 import { FormBuilderService } from '../../../../shared/form/builder/form-builder.service';
 import { NotificationsService } from '../../../../shared/notifications/notifications.service';
@@ -28,6 +31,7 @@ import { FeatureID } from '../../../../core/data/feature-authorization/feature-i
 import { ConfirmationModalComponent } from '../../../../shared/confirmation-modal/confirmation-modal.component';
 import { NgbModal } from '@ng-bootstrap/ng-bootstrap';
 import { RequestService } from '../../../../core/data/request.service';
+import { NoContent } from '../../../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-eperson-form',
@@ -314,9 +318,11 @@ export class EPersonFormComponent implements OnInit, OnDestroy {
   createNewEPerson(values) {
     const ePersonToCreate = Object.assign(new EPerson(), values);
 
-    const response = this.epersonService.tryToCreate(ePersonToCreate);
-    response.pipe(take(1)).subscribe((restResponse: RestResponse) => {
-      if (restResponse.isSuccessful) {
+    const response = this.epersonService.create(ePersonToCreate);
+    response.pipe(
+      getFirstCompletedRemoteData()
+    ).subscribe((rd: RemoteData<EPerson>) => {
+      if (rd.hasSucceeded) {
         this.notificationsService.success(this.translateService.get(this.labelPrefix + 'notification.created.success', { name: ePersonToCreate.name }));
         this.submitForm.emit(ePersonToCreate);
       } else {
@@ -354,8 +360,8 @@ export class EPersonFormComponent implements OnInit, OnDestroy {
     });
 
     const response = this.epersonService.updateEPerson(editedEperson);
-    response.pipe(take(1)).subscribe((restResponse: RestResponse) => {
-      if (restResponse.isSuccessful) {
+    response.pipe(take(1)).subscribe((rd: RemoteData<EPerson>) => {
+      if (rd.hasSucceeded) {
         this.notificationsService.success(this.translateService.get(this.labelPrefix + 'notification.edited.success', { name: editedEperson.name }));
         this.submitForm.emit(editedEperson);
       } else {
@@ -380,7 +386,7 @@ export class EPersonFormComponent implements OnInit, OnDestroy {
     this.subs.push(this.epersonService.searchByScope('email', ePerson.email, {
       currentPage: 1,
       elementsPerPage: 0
-    }).pipe(getSucceededRemoteData(), getRemoteDataPayload())
+    }).pipe(getFirstSucceededRemoteData(), getRemoteDataPayload())
       .subscribe((list: PaginatedList<EPerson>) => {
         if (list.totalElements > 0) {
           this.notificationsService.error(this.translateService.get(this.labelPrefix + 'notification.' + notificationSection + '.failure.emailInUse', {
@@ -434,12 +440,12 @@ export class EPersonFormComponent implements OnInit, OnDestroy {
         modalRef.componentInstance.response.pipe(take(1)).subscribe((confirm: boolean) => {
           if (confirm) {
             if (hasValue(eperson.id)) {
-              this.epersonService.deleteEPerson(eperson).pipe(take(1)).subscribe((restResponse: RestResponse) => {
-                if (restResponse.isSuccessful) {
+              this.epersonService.deleteEPerson(eperson).pipe(take(1)).subscribe((restResponse: RemoteData<NoContent>) => {
+                if (restResponse.hasSucceeded) {
                   this.notificationsService.success(this.translateService.get(this.labelPrefix + 'notification.deleted.success', { name: eperson.name }));
                   this.reset();
                 } else {
-                  this.notificationsService.error('Error occured when trying to delete EPerson with id: ' + eperson.id + ' with code: ' + restResponse.statusCode + ' and message: ' + restResponse.statusText);
+                  this.notificationsService.error('Error occured when trying to delete EPerson with id: ' + eperson.id + ' with code: ' + restResponse.statusCode + ' and message: ' + restResponse.errorMessage);
                 }
                 this.cancelForm.emit();
               })

src/app/+admin/admin-access-control/group-registry/group-form/group-form.component.spec.ts

@@ -12,11 +12,10 @@ import { of as observableOf } from 'rxjs';
 import { Observable } from 'rxjs/internal/Observable';
 import { RemoteDataBuildService } from '../../../../core/cache/builders/remote-data-build.service';
 import { ObjectCacheService } from '../../../../core/cache/object-cache.service';
-import { RestResponse } from '../../../../core/cache/response.models';
 import { DSOChangeAnalyzer } from '../../../../core/data/dso-change-analyzer.service';
 import { DSpaceObjectDataService } from '../../../../core/data/dspace-object-data.service';
 import { AuthorizationDataService } from '../../../../core/data/feature-authorization/authorization-data.service';
-import { PaginatedList } from '../../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../core/data/remote-data';
 import { EPersonDataService } from '../../../../core/eperson/eperson-data.service';
 import { GroupDataService } from '../../../../core/eperson/group-data.service';
@@ -35,6 +34,7 @@ import { getMockTranslateService } from '../../../../shared/mocks/translate.serv
 import { TranslateLoaderMock } from '../../../../shared/testing/translate-loader.mock';
 import { RouterMock } from '../../../../shared/mocks/router.mock';
 import { NotificationsServiceStub } from '../../../../shared/testing/notifications-service.stub';
+import { Operation } from 'fast-json-patch';
 
 describe('GroupFormComponent', () => {
   let component: GroupFormComponent;
@@ -71,6 +71,7 @@ describe('GroupFormComponent', () => {
     groupsDataServiceStub = {
       allGroups: groups,
       activeGroup: null,
+      createdGroup: null,
       getActiveGroup(): Observable<Group> {
         return observableOf(this.activeGroup);
       },
@@ -80,7 +81,10 @@ describe('GroupFormComponent', () => {
       editGroup(group: Group) {
         this.activeGroup = group
       },
-      updateGroup(group: Group) {
+      clearGroupsRequests() {
+        return null;
+      },
+      patch(group: Group, operations: Operation[]) {
         return null;
       },
       cancelEditGroup(): void {
@@ -89,12 +93,21 @@ describe('GroupFormComponent', () => {
       findById(id: string) {
         return observableOf({ payload: null, hasSucceeded: true });
       },
-      tryToCreate(group: Group): Observable<RestResponse> {
-        this.allGroups = [...this.allGroups, group]
-        return observableOf(new RestResponse(true, 200, 'Success'));
+      findByHref(href: string) {
+        return createSuccessfulRemoteDataObject$(this.createdGroup);
+      },
+      create(group: Group): Observable<RemoteData<Group>> {
+        this.allGroups = [...this.allGroups, group];
+        this.createdGroup = Object.assign({}, group, {
+          _links: { self: { href: 'group-selflink' } }
+        });
+        return createSuccessfulRemoteDataObject$(this.createdGroup);
       },
       searchGroups(query: string): Observable<RemoteData<PaginatedList<Group>>> {
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), []))
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), []))
+      },
+      getGroupEditPageRouterLinkWithID(id: string) {
+        return `group-edit-page-for-${id}`;
       }
     };
     authorizationService = jasmine.createSpyObj('authorizationService', {
@@ -171,7 +184,7 @@ describe('GroupFormComponent', () => {
     describe('with active Group', () => {
       beforeEach(() => {
         spyOn(groupsDataServiceStub, 'getActiveGroup').and.returnValue(observableOf(expected));
-        spyOn(groupsDataServiceStub, 'updateGroup').and.returnValue(observableOf(new RestResponse(true, 200, 'OK')));
+        spyOn(groupsDataServiceStub, 'patch').and.returnValue(createSuccessfulRemoteDataObject$(expected));
         component.groupName.value = 'newGroupName';
         component.onSubmit();
         fixture.detectChanges();

src/app/+admin/admin-access-control/group-registry/group-form/group-form.component.ts

@@ -9,15 +9,20 @@ import {
   DynamicTextAreaModel
 } from '@ng-dynamic-forms/core';
 import { TranslateService } from '@ngx-translate/core';
-import { ObservedValueOf, combineLatest as observableCombineLatest, Observable, of as observableOf, Subscription } from 'rxjs';
+import {
+  ObservedValueOf,
+  combineLatest as observableCombineLatest,
+  Observable,
+  of as observableOf,
+  Subscription
+} from 'rxjs';
 import { catchError, map, switchMap, take } from 'rxjs/operators';
 import { getCollectionEditRolesRoute } from '../../../../+collection-page/collection-page-routing-paths';
 import { getCommunityEditRolesRoute } from '../../../../+community-page/community-page-routing-paths';
-import { RestResponse } from '../../../../core/cache/response.models';
 import { DSpaceObjectDataService } from '../../../../core/data/dspace-object-data.service';
 import { AuthorizationDataService } from '../../../../core/data/feature-authorization/authorization-data.service';
 import { FeatureID } from '../../../../core/data/feature-authorization/feature-id';
-import { PaginatedList } from '../../../../core/data/paginated-list';
+import { PaginatedList } from '../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../core/data/remote-data';
 import { RequestService } from '../../../../core/data/request.service';
 import { EPersonDataService } from '../../../../core/eperson/eperson-data.service';
@@ -26,13 +31,19 @@ import { Group } from '../../../../core/eperson/models/group.model';
 import { Collection } from '../../../../core/shared/collection.model';
 import { Community } from '../../../../core/shared/community.model';
 import { DSpaceObject } from '../../../../core/shared/dspace-object.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../../core/shared/operators';
+import {
+  getRemoteDataPayload,
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
+} from '../../../../core/shared/operators';
 import { AlertType } from '../../../../shared/alert/aletr-type';
 import { ConfirmationModalComponent } from '../../../../shared/confirmation-modal/confirmation-modal.component';
-import { hasValue, isNotEmpty } from '../../../../shared/empty.util';
+import { hasValue, isNotEmpty, hasValueOperator } from '../../../../shared/empty.util';
 import { FormBuilderService } from '../../../../shared/form/builder/form-builder.service';
 import { NotificationsService } from '../../../../shared/notifications/notifications.service';
 import { followLink } from '../../../../shared/utils/follow-link-config.model';
+import { NoContent } from '../../../../core/shared/NoContent.model';
+import { Operation } from 'fast-json-patch';
 
 @Component({
   selector: 'ds-group-form',
@@ -135,6 +146,7 @@ export class GroupFormComponent implements OnInit, OnDestroy {
       this.setActiveGroup(params.groupId)
     }));
     this.canEdit$ = this.groupDataService.getActiveGroup().pipe(
+      hasValueOperator(),
       switchMap((group: Group) => {
         return observableCombineLatest(
           this.authorizationService.isAuthorized(FeatureID.CanDelete, hasValue(group) ? group.self : undefined),
@@ -231,17 +243,17 @@ export class GroupFormComponent implements OnInit, OnDestroy {
    */
   createNewGroup(values) {
     const groupToCreate = Object.assign(new Group(), values);
-    const response = this.groupDataService.tryToCreate(groupToCreate);
-    response.pipe(take(1)).subscribe((restResponse: RestResponse) => {
-      if (restResponse.isSuccessful) {
+    this.groupDataService.create(groupToCreate).pipe(
+      getFirstCompletedRemoteData()
+    ).subscribe((rd: RemoteData<Group>) => {
+      if (rd.hasSucceeded) {
         this.notificationsService.success(this.translateService.get(this.messagePrefix + '.notification.created.success', { name: groupToCreate.name }));
         this.submitForm.emit(groupToCreate);
-        const resp: any = restResponse;
-        if (isNotEmpty(resp.resourceSelfLinks)) {
-          const groupSelfLink = resp.resourceSelfLinks[0];
+        if (isNotEmpty(rd.payload)) {
+          const groupSelfLink = rd.payload._links.self.href;
           this.setActiveGroupWithLink(groupSelfLink);
           this.groupDataService.clearGroupsRequests();
-          this.router.navigateByUrl(this.groupDataService.getGroupEditPageRouterLinkWithID(this.groupDataService.getUUIDFromString(groupSelfLink)));
+          this.router.navigateByUrl(this.groupDataService.getGroupEditPageRouterLinkWithID(rd.payload.uuid));
         }
       } else {
         this.notificationsService.error(this.translateService.get(this.messagePrefix + '.notification.created.failure', { name: groupToCreate.name }));
@@ -262,7 +274,7 @@ export class GroupFormComponent implements OnInit, OnDestroy {
     this.subs.push(this.groupDataService.searchGroups(group.name, {
       currentPage: 1,
       elementsPerPage: 0
-    }).pipe(getSucceededRemoteData(), getRemoteDataPayload())
+    }).pipe(getFirstSucceededRemoteData(), getRemoteDataPayload())
       .subscribe((list: PaginatedList<Group>) => {
         if (list.totalElements > 0) {
           this.notificationsService.error(this.translateService.get(this.messagePrefix + '.notification.' + notificationSection + '.failure.groupNameInUse', {
@@ -277,25 +289,32 @@ export class GroupFormComponent implements OnInit, OnDestroy {
    * @param group   Group to edit and old values contained within
    */
   editGroup(group: Group) {
-    const editedGroup = Object.assign(new Group(), {
-      id: group.id,
-      metadata: {
-        'dc.description': [
-          {
-            value: (hasValue(this.groupDescription.value) ? this.groupDescription.value : group.firstMetadataValue('dc.description'))
+    let operations: Operation[] = []
+
+    if (hasValue(this.groupDescription.value)) {
+      operations = [...operations, {
+        op: 'replace',
+        path: '/metadata/dc.description/0/value',
+        value: this.groupDescription.value
+      }];
     }
-        ],
-      },
-      name: (hasValue(this.groupName.value) ? this.groupName.value : group.name),
-      _links: group._links,
-    });
-    const response = this.groupDataService.updateGroup(editedGroup);
-    response.pipe(take(1)).subscribe((restResponse: RestResponse) => {
-      if (restResponse.isSuccessful) {
-        this.notificationsService.success(this.translateService.get(this.messagePrefix + '.notification.edited.success', { name: editedGroup.name }));
-        this.submitForm.emit(editedGroup);
+
+    if (hasValue(this.groupName.value)) {
+      operations = [...operations, {
+        op: 'replace',
+        path: '/name',
+        value: this.groupName.value
+      }];
+    }
+
+    this.groupDataService.patch(group, operations).pipe(
+      getFirstCompletedRemoteData()
+    ).subscribe((rd: RemoteData<Group>) => {
+      if (rd.hasSucceeded) {
+        this.notificationsService.success(this.translateService.get(this.messagePrefix + '.notification.edited.success', { name: rd.payload.name }));
+        this.submitForm.emit(rd.payload);
       } else {
-        this.notificationsService.error(this.translateService.get(this.messagePrefix + '.notification.edited.failure', { name: editedGroup.name }));
+        this.notificationsService.error(this.translateService.get(this.messagePrefix + '.notification.edited.failure', { name: group.name }));
         this.cancelForm.emit();
       }
     });
@@ -309,7 +328,7 @@ export class GroupFormComponent implements OnInit, OnDestroy {
     this.groupDataService.cancelEditGroup();
     this.groupDataService.findById(groupId)
       .pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload())
       .subscribe((group: Group) => {
         this.groupDataService.editGroup(group);
@@ -324,9 +343,9 @@ export class GroupFormComponent implements OnInit, OnDestroy {
     this.groupDataService.getActiveGroup().pipe(take(1)).subscribe((activeGroup: Group) => {
       if (activeGroup === null) {
         this.groupDataService.cancelEditGroup();
-        this.groupDataService.findByHref(groupSelfLink, followLink('subgroups'), followLink('epersons'), followLink('object'))
+        this.groupDataService.findByHref(groupSelfLink, false, followLink('subgroups'), followLink('epersons'), followLink('object'))
           .pipe(
-            getSucceededRemoteData(),
+            getFirstSucceededRemoteData(),
             getRemoteDataPayload())
           .subscribe((group: Group) => {
             this.groupDataService.editGroup(group);
@@ -350,15 +369,15 @@ export class GroupFormComponent implements OnInit, OnDestroy {
       modalRef.componentInstance.response.pipe(take(1)).subscribe((confirm: boolean) => {
         if (confirm) {
           if (hasValue(group.id)) {
-            this.groupDataService.deleteGroup(group).pipe(take(1))
-              .subscribe(([success, optionalErrorMessage]: [boolean, string]) => {
-                if (success) {
+            this.groupDataService.delete(group.id).pipe(getFirstCompletedRemoteData())
+              .subscribe((rd: RemoteData<NoContent>) => {
+                if (rd.hasSucceeded) {
                   this.notificationsService.success(this.translateService.get(this.messagePrefix + '.notification.deleted.success', { name: group.name }));
                   this.reset();
                 } else {
                   this.notificationsService.error(
                     this.translateService.get(this.messagePrefix + '.notification.deleted.failure.title', { name: group.name }),
-                    this.translateService.get(this.messagePrefix + '.notification.deleted.failure.content', { cause: optionalErrorMessage }));
+                    this.translateService.get(this.messagePrefix + '.notification.deleted.failure.content', { cause: rd.errorMessage }));
                 }
               })
           }

src/app/+admin/admin-access-control/group-registry/group-form/members-list/members-list.component.html

@@ -24,7 +24,7 @@
     </div>
   </form>
 
-  <ds-pagination *ngIf="(ePeopleSearch | async)?.payload.totalElements > 0"
+  <ds-pagination *ngIf="(ePeopleSearch | async)?.payload?.totalElements > 0"
                  [paginationOptions]="configSearch"
                  [pageInfoState]="(ePeopleSearch | async)?.payload"
                  [collectionSize]="(ePeopleSearch | async)?.payload?.totalElements"
@@ -70,7 +70,7 @@
 
   </ds-pagination>
 
-  <div *ngIf="(ePeopleSearch | async)?.payload.totalElements == 0 && searchDone"
+  <div *ngIf="(ePeopleSearch | async)?.payload?.totalElements == 0 && searchDone"
        class="alert alert-info w-100 mb-2"
        role="alert">
     {{messagePrefix + '.no-items' | translate}}
@@ -78,7 +78,7 @@
 
   <h4>{{messagePrefix + '.headMembers' | translate}}</h4>
 
-  <ds-pagination *ngIf="(ePeopleMembersOfGroup | async)?.payload.totalElements > 0"
+  <ds-pagination *ngIf="(ePeopleMembersOfGroup | async)?.payload?.totalElements > 0"
                  [paginationOptions]="config"
                  [pageInfoState]="(ePeopleMembersOfGroup | async)?.payload"
                  [collectionSize]="(ePeopleMembersOfGroup | async)?.payload?.totalElements"
@@ -116,7 +116,7 @@
 
   </ds-pagination>
 
-  <div *ngIf="(ePeopleMembersOfGroup | async)?.payload.totalElements == 0" class="alert alert-info w-100 mb-2"
+  <div *ngIf="(ePeopleMembersOfGroup | async)?.payload?.totalElements == 0" class="alert alert-info w-100 mb-2"
        role="alert">
     {{messagePrefix + '.no-members-yet' | translate}}
   </div>

src/app/+admin/admin-access-control/group-registry/group-form/members-list/members-list.component.spec.ts

@@ -1,6 +1,14 @@
 import { CommonModule } from '@angular/common';
 import { NO_ERRORS_SCHEMA } from '@angular/core';
-import { async, ComponentFixture, fakeAsync, flush, inject, TestBed, tick } from '@angular/core/testing';
+import {
+  async,
+  ComponentFixture,
+  fakeAsync,
+  flush,
+  inject,
+  TestBed,
+  tick
+} from '@angular/core/testing';
 import { FormsModule, ReactiveFormsModule } from '@angular/forms';
 import { BrowserModule, By } from '@angular/platform-browser';
 import { Router } from '@angular/router';
@@ -8,7 +16,7 @@ import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateLoader, TranslateModule, TranslateService } from '@ngx-translate/core';
 import { Observable } from 'rxjs/internal/Observable';
 import { RestResponse } from '../../../../../core/cache/response.models';
-import { PaginatedList } from '../../../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../../core/data/remote-data';
 import { EPersonDataService } from '../../../../../core/eperson/eperson-data.service';
 import { GroupDataService } from '../../../../../core/eperson/group-data.service';
@@ -52,13 +60,13 @@ describe('MembersListComponent', () => {
       epersonMembers: epersonMembers,
       subgroupMembers: subgroupMembers,
       findAllByHref(href: string): Observable<RemoteData<PaginatedList<EPerson>>> {
-        return createSuccessfulRemoteDataObject$(new PaginatedList<EPerson>(new PageInfo(), groupsDataServiceStub.getEPersonMembers()))
+        return createSuccessfulRemoteDataObject$(buildPaginatedList<EPerson>(new PageInfo(), groupsDataServiceStub.getEPersonMembers()))
       },
       searchByScope(scope: string, query: string): Observable<RemoteData<PaginatedList<EPerson>>> {
         if (query === '') {
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), allEPersons))
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), allEPersons))
         }
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), []))
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), []))
       },
       clearEPersonRequests() {
         // empty
@@ -83,9 +91,9 @@ describe('MembersListComponent', () => {
       },
       searchGroups(query: string): Observable<RemoteData<PaginatedList<Group>>> {
         if (query === '') {
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), this.allGroups))
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), this.allGroups))
         }
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), []))
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), []))
       },
       addMemberToGroup(parentGroup, eperson: EPerson): Observable<RestResponse> {
         this.epersonMembers = [...this.epersonMembers, eperson];

src/app/+admin/admin-access-control/group-registry/group-form/members-list/members-list.component.ts

@@ -4,14 +4,17 @@ import { Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
 import { Observable, of as observableOf, Subscription } from 'rxjs';
 import { map, mergeMap, take } from 'rxjs/operators';
-import { RestResponse } from '../../../../../core/cache/response.models';
-import { PaginatedList } from '../../../../../core/data/paginated-list';
+import { PaginatedList } from '../../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../../core/data/remote-data';
 import { EPersonDataService } from '../../../../../core/eperson/eperson-data.service';
 import { GroupDataService } from '../../../../../core/eperson/group-data.service';
 import { EPerson } from '../../../../../core/eperson/models/eperson.model';
 import { Group } from '../../../../../core/eperson/models/group.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../../../core/shared/operators';
+import {
+  getRemoteDataPayload,
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
+} from '../../../../../core/shared/operators';
 import { hasValue } from '../../../../../shared/empty.util';
 import { NotificationsService } from '../../../../../shared/notifications/notifications.service';
 import { PaginationComponentOptions } from '../../../../../shared/pagination/pagination-component-options.model';
@@ -160,7 +163,7 @@ export class MembersListComponent implements OnInit, OnDestroy {
             elementsPerPage: Number.MAX_SAFE_INTEGER
           })
             .pipe(
-              getSucceededRemoteData(),
+              getFirstSucceededRemoteData(),
               getRemoteDataPayload(),
               map((listEPeopleInGroup: PaginatedList<EPerson>) => listEPeopleInGroup.page.filter((ePersonInList: EPerson) => ePersonInList.id === possibleMember.id)),
               map((epeople: EPerson[]) => epeople.length > 0))
@@ -225,9 +228,9 @@ export class MembersListComponent implements OnInit, OnDestroy {
    * @param nameObject      Object request was about
    * @param activeGroup     Group currently being edited
    */
-  showNotifications(messageSuffix: string, response: Observable<RestResponse>, nameObject: string, activeGroup: Group) {
-    response.pipe(take(1)).subscribe((restResponse: RestResponse) => {
-      if (restResponse.isSuccessful) {
+  showNotifications(messageSuffix: string, response: Observable<RemoteData<any>>, nameObject: string, activeGroup: Group) {
+    response.pipe(getFirstCompletedRemoteData()).subscribe((rd: RemoteData<any>) => {
+      if (rd.hasSucceeded) {
         this.notificationsService.success(this.translateService.get(this.messagePrefix + '.notification.success.' + messageSuffix, { name: nameObject }));
       } else {
         this.notificationsService.error(this.translateService.get(this.messagePrefix + '.notification.failure.' + messageSuffix, { name: nameObject }));

src/app/+admin/admin-access-control/group-registry/group-form/subgroup-list/subgroups-list.component.html

@@ -18,7 +18,7 @@
     </div>
   </form>
 
-  <ds-pagination *ngIf="(groupsSearch | async)?.payload.totalElements > 0"
+  <ds-pagination *ngIf="(groupsSearch | async)?.payload?.totalElements > 0"
                  [paginationOptions]="configSearch"
                  [pageInfoState]="(groupsSearch | async)?.payload"
                  [collectionSize]="(groupsSearch | async)?.payload?.totalElements"
@@ -65,14 +65,14 @@
     </div>
   </ds-pagination>
 
-  <div *ngIf="(groupsSearch | async)?.payload.totalElements == 0 && searchDone" class="alert alert-info w-100 mb-2"
+  <div *ngIf="(groupsSearch | async)?.payload?.totalElements == 0 && searchDone" class="alert alert-info w-100 mb-2"
        role="alert">
     {{messagePrefix + '.no-items' | translate}}
   </div>
 
   <h4>{{messagePrefix + '.headSubgroups' | translate}}</h4>
 
-  <ds-pagination *ngIf="(subgroupsOfGroup | async)?.payload.totalElements > 0"
+  <ds-pagination *ngIf="(subgroupsOfGroup | async)?.payload?.totalElements > 0"
                  [paginationOptions]="config"
                  [pageInfoState]="(subgroupsOfGroup | async)?.payload"
                  [collectionSize]="(subgroupsOfGroup | async)?.payload?.totalElements"
@@ -109,7 +109,7 @@
     </div>
   </ds-pagination>
 
-  <div *ngIf="(subgroupsOfGroup | async)?.payload.totalElements == 0" class="alert alert-info w-100 mb-2"
+  <div *ngIf="(subgroupsOfGroup | async)?.payload?.totalElements == 0" class="alert alert-info w-100 mb-2"
        role="alert">
     {{messagePrefix + '.no-subgroups-yet' | translate}}
   </div>

src/app/+admin/admin-access-control/group-registry/group-form/subgroup-list/subgroups-list.component.spec.ts

@@ -8,7 +8,7 @@ import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateLoader, TranslateModule, TranslateService } from '@ngx-translate/core';
 import { Observable } from 'rxjs/internal/Observable';
 import { RestResponse } from '../../../../../core/cache/response.models';
-import { PaginatedList } from '../../../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../../core/data/remote-data';
 import { GroupDataService } from '../../../../../core/eperson/group-data.service';
 import { Group } from '../../../../../core/eperson/models/group.model';
@@ -52,16 +52,16 @@ describe('SubgroupsListComponent', () => {
         return this.activeGroup;
       },
       findAllByHref(href: string): Observable<RemoteData<PaginatedList<Group>>> {
-        return createSuccessfulRemoteDataObject$(new PaginatedList<Group>(new PageInfo(), this.subgroups))
+        return createSuccessfulRemoteDataObject$(buildPaginatedList<Group>(new PageInfo(), this.subgroups))
       },
       getGroupEditPageRouterLink(group: Group): string {
         return '/admin/access-control/groups/' + group.id;
       },
       searchGroups(query: string): Observable<RemoteData<PaginatedList<Group>>> {
         if (query === '') {
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), allGroups))
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), allGroups))
         }
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), []))
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), []))
       },
       addSubGroupToGroup(parentGroup, subgroup: Group): Observable<RestResponse> {
         this.subgroups = [...this.subgroups, subgroup];

src/app/+admin/admin-access-control/group-registry/group-form/subgroup-list/subgroups-list.component.ts

@@ -4,12 +4,15 @@ import { Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
 import { Observable, of as observableOf, Subscription } from 'rxjs';
 import { map, mergeMap, take } from 'rxjs/operators';
-import { RestResponse } from '../../../../../core/cache/response.models';
-import { PaginatedList } from '../../../../../core/data/paginated-list';
+import { PaginatedList } from '../../../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../../../core/data/remote-data';
 import { GroupDataService } from '../../../../../core/eperson/group-data.service';
 import { Group } from '../../../../../core/eperson/models/group.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../../../core/shared/operators';
+import {
+  getRemoteDataPayload,
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
+} from '../../../../../core/shared/operators';
 import { hasValue } from '../../../../../shared/empty.util';
 import { NotificationsService } from '../../../../../shared/notifications/notifications.service';
 import { PaginationComponentOptions } from '../../../../../shared/pagination/pagination-component-options.model';
@@ -125,7 +128,7 @@ export class SubgroupsListComponent implements OnInit, OnDestroy {
               elementsPerPage: Number.MAX_SAFE_INTEGER
             })
               .pipe(
-                getSucceededRemoteData(),
+                getFirstSucceededRemoteData(),
                 getRemoteDataPayload(),
                 map((listTotalGroups: PaginatedList<Group>) => listTotalGroups.page.filter((groupInList: Group) => groupInList.id === possibleSubgroup.id)),
                 map((groups: Group[]) => groups.length > 0))
@@ -231,9 +234,9 @@ export class SubgroupsListComponent implements OnInit, OnDestroy {
    * @param nameObject      Object request was about
    * @param activeGroup     Group currently being edited
    */
-  showNotifications(messageSuffix: string, response: Observable<RestResponse>, nameObject: string, activeGroup: Group) {
-    response.pipe(take(1)).subscribe((restResponse: RestResponse) => {
-      if (restResponse.isSuccessful) {
+  showNotifications(messageSuffix: string, response: Observable<RemoteData<Group>>, nameObject: string, activeGroup: Group) {
+    response.pipe(getFirstCompletedRemoteData()).subscribe((rd: RemoteData<Group>) => {
+      if (rd.hasSucceeded) {
         this.notificationsService.success(this.translateService.get(this.messagePrefix + '.notification.success.' + messageSuffix, { name: nameObject }));
       } else {
         this.notificationsService.error(this.translateService.get(this.messagePrefix + '.notification.failure.' + messageSuffix, { name: nameObject }));

src/app/+admin/admin-access-control/group-registry/groups-registry.component.spec.ts

@@ -9,7 +9,7 @@ import { TranslateLoader, TranslateModule } from '@ngx-translate/core';
 import { Observable, of as observableOf } from 'rxjs';
 import { DSpaceObjectDataService } from '../../../core/data/dspace-object-data.service';
 import { AuthorizationDataService } from '../../../core/data/feature-authorization/authorization-data.service';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../core/data/remote-data';
 import { RequestService } from '../../../core/data/request.service';
 import { EPersonDataService } from '../../../core/eperson/eperson-data.service';
@@ -47,11 +47,11 @@ describe('GroupRegistryComponent', () => {
       findAllByHref(href: string): Observable<RemoteData<PaginatedList<EPerson>>> {
         switch (href) {
           case 'https://dspace.4science.it/dspace-spring-rest/api/eperson/groups/testgroupid2/epersons':
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
           case 'https://dspace.4science.it/dspace-spring-rest/api/eperson/groups/testgroupid/epersons':
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 1, totalPages: 1, currentPage: 1 }), [EPersonMock]));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 1, totalPages: 1, currentPage: 1 }), [EPersonMock]));
           default:
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
         }
       }
     };
@@ -60,11 +60,11 @@ describe('GroupRegistryComponent', () => {
       findAllByHref(href: string): Observable<RemoteData<PaginatedList<Group>>> {
         switch (href) {
           case 'https://dspace.4science.it/dspace-spring-rest/api/eperson/groups/testgroupid2/groups':
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
           case 'https://dspace.4science.it/dspace-spring-rest/api/eperson/groups/testgroupid/groups':
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 1, totalPages: 1, currentPage: 1 }), [GroupMock2]));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 1, totalPages: 1, currentPage: 1 }), [GroupMock2]));
           default:
-            return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
+            return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: 1, totalElements: 0, totalPages: 0, currentPage: 1 }), []));
         }
       },
       getGroupEditPageRouterLink(group: Group): string {
@@ -75,12 +75,12 @@ describe('GroupRegistryComponent', () => {
       },
       searchGroups(query: string): Observable<RemoteData<PaginatedList<Group>>> {
         if (query === '') {
-          return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: this.allGroups.length, totalElements: this.allGroups.length, totalPages: 1, currentPage: 1 }), this.allGroups));
+          return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: this.allGroups.length, totalElements: this.allGroups.length, totalPages: 1, currentPage: 1 }), this.allGroups));
         }
         const result = this.allGroups.find((group: Group) => {
           return (group.id.includes(query))
         });
-        return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo({ elementsPerPage: [result].length, totalElements: [result].length, totalPages: 1, currentPage: 1 }), [result]));
+        return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo({ elementsPerPage: [result].length, totalElements: [result].length, totalPages: 1, currentPage: 1 }), [result]));
       }
     };
     dsoDataServiceStub = {

src/app/+admin/admin-access-control/group-registry/groups-registry.component.ts

@@ -2,14 +2,20 @@ import { Component, OnDestroy, OnInit } from '@angular/core';
 import { FormBuilder } from '@angular/forms';
 import { Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
-import { BehaviorSubject, combineLatest as observableCombineLatest, Subscription, Observable, of as observableOf } from 'rxjs';
+import {
+  BehaviorSubject,
+  combineLatest as observableCombineLatest,
+  Subscription,
+  Observable,
+  of as observableOf
+} from 'rxjs';
 import { filter } from 'rxjs/internal/operators/filter';
 import { ObservedValueOf } from 'rxjs/internal/types';
 import { catchError, map, switchMap, take } from 'rxjs/operators';
 import { DSpaceObjectDataService } from '../../../core/data/dspace-object-data.service';
 import { AuthorizationDataService } from '../../../core/data/feature-authorization/authorization-data.service';
 import { FeatureID } from '../../../core/data/feature-authorization/feature-id';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { RemoteData } from '../../../core/data/remote-data';
 import { RequestService } from '../../../core/data/request.service';
 import { EPersonDataService } from '../../../core/eperson/eperson-data.service';
@@ -19,11 +25,15 @@ import { GroupDtoModel } from '../../../core/eperson/models/group-dto.model';
 import { Group } from '../../../core/eperson/models/group.model';
 import { RouteService } from '../../../core/services/route.service';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
-import { getAllSucceededRemoteDataPayload } from '../../../core/shared/operators';
+import {
+  getAllSucceededRemoteDataPayload,
+  getFirstCompletedRemoteData
+} from '../../../core/shared/operators';
 import { PageInfo } from '../../../core/shared/page-info.model';
 import { hasValue } from '../../../shared/empty.util';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { PaginationComponentOptions } from '../../../shared/pagination/pagination-component-options.model';
+import { NoContent } from '../../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-groups-registry',
@@ -115,7 +125,8 @@ export class GroupsRegistryComponent implements OnInit, OnDestroy {
     this.subs.push(this.groupService.searchGroups(this.currentSearchQuery.trim(), {
       currentPage: this.config.currentPage,
       elementsPerPage: this.config.pageSize
-    }).subscribe((groupsRD: RemoteData<PaginatedList<Group>>) => {
+    }).pipe(getFirstCompletedRemoteData())
+      .subscribe((groupsRD: RemoteData<PaginatedList<Group>>) => {
         this.groups$.next(groupsRD);
         this.pageInfoState$.next(groupsRD.payload.pageInfo);
       }
@@ -136,7 +147,7 @@ export class GroupsRegistryComponent implements OnInit, OnDestroy {
             }
           )
         })).pipe(map((dtos: GroupDtoModel[]) => {
-          return new PaginatedList(groups.pageInfo, dtos);
+          return buildPaginatedList(groups.pageInfo, dtos);
         }))
       })).subscribe((value: PaginatedList<GroupDtoModel>) => {
       this.groupsDto$.next(value);
@@ -149,15 +160,15 @@ export class GroupsRegistryComponent implements OnInit, OnDestroy {
    */
   deleteGroup(group: Group) {
     if (hasValue(group.id)) {
-      this.groupService.deleteGroup(group).pipe(take(1))
-        .subscribe(([success, optionalErrorMessage]: [boolean, string]) => {
-          if (success) {
+      this.groupService.delete(group.id).pipe(getFirstCompletedRemoteData())
+        .subscribe((rd: RemoteData<NoContent>) => {
+          if (rd.hasSucceeded) {
             this.notificationsService.success(this.translateService.get(this.messagePrefix + 'notification.deleted.success', { name: group.name }));
             this.reset();
           } else {
             this.notificationsService.error(
               this.translateService.get(this.messagePrefix + 'notification.deleted.failure.title', { name: group.name }),
-              this.translateService.get(this.messagePrefix + 'notification.deleted.failure.content', { cause: optionalErrorMessage }));
+              this.translateService.get(this.messagePrefix + 'notification.deleted.failure.content', { cause: rd.errorMessage }));
           }
         })
     }

src/app/+admin/admin-import-metadata-page/metadata-import-page.component.spec.ts

@@ -19,6 +19,7 @@ import { NotificationsServiceStub } from '../../shared/testing/notifications-ser
 import { FileValueAccessorDirective } from '../../shared/utils/file-value-accessor.directive';
 import { FileValidator } from '../../shared/utils/require-file.validator';
 import { MetadataImportPageComponent } from './metadata-import-page.component';
+import { createFailedRemoteDataObject$, createSuccessfulRemoteDataObject$ } from '../../shared/remote-data.utils';
 
 describe('MetadataImportPageComponent', () => {
   let comp: MetadataImportPageComponent;
@@ -36,13 +37,7 @@ describe('MetadataImportPageComponent', () => {
     notificationService = new NotificationsServiceStub();
     scriptService = jasmine.createSpyObj('scriptService',
       {
-        invoke: observableOf({
-          response:
-            {
-              isSuccessful: true,
-              resourceSelfLinks: ['https://localhost:8080/api/core/processes/45']
-            }
-        })
+        invoke: createSuccessfulRemoteDataObject$({ processId: '45' })
       }
     );
     user = Object.assign(new EPerson(), {
@@ -133,12 +128,7 @@ describe('MetadataImportPageComponent', () => {
     describe('if proceed is pressed; but script invoke fails', () => {
       beforeEach(fakeAsync(() => {
         jasmine.getEnv().allowRespy(true);
-        spyOn(scriptService, 'invoke').and.returnValue(observableOf({
-          response:
-            {
-              isSuccessful: false,
-            }
-        }));
+        spyOn(scriptService, 'invoke').and.returnValue(createFailedRemoteDataObject$('Error', 500));
         const proceed = fixture.debugElement.query(By.css('#proceedButton')).nativeElement;
         proceed.click();
         fixture.detectChanges();

src/app/+admin/admin-import-metadata-page/metadata-import-page.component.ts

@@ -3,14 +3,20 @@ import { Component, OnInit } from '@angular/core';
 import { Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
 import { Observable } from 'rxjs/internal/Observable';
-import { map, switchMap, take } from 'rxjs/operators';
+import { map, switchMap } from 'rxjs/operators';
 import { AuthService } from '../../core/auth/auth.service';
-import { METADATA_IMPORT_SCRIPT_NAME, ScriptDataService } from '../../core/data/processes/script-data.service';
-import { RequestEntry } from '../../core/data/request.reducer';
+import {
+  METADATA_IMPORT_SCRIPT_NAME,
+  ScriptDataService
+} from '../../core/data/processes/script-data.service';
 import { EPerson } from '../../core/eperson/models/eperson.model';
 import { ProcessParameter } from '../../process-page/processes/process-parameter.model';
 import { isNotEmpty } from '../../shared/empty.util';
 import { NotificationsService } from '../../shared/notifications/notifications.service';
+import { RemoteData } from '../../core/data/remote-data';
+import { Process } from '../../process-page/processes/process.model';
+import { getFirstCompletedRemoteData } from '../../core/shared/operators';
+import { getProcessDetailRoute } from '../../process-page/process-page-routing.paths';
 
 @Component({
   selector: 'ds-metadata-import-page',
@@ -79,28 +85,23 @@ export class MetadataImportPageComponent implements OnInit {
               Object.assign(new ProcessParameter(), { name: '-f', value: this.fileObject.name }),
             ];
             return this.scriptDataService.invoke(METADATA_IMPORT_SCRIPT_NAME, parameterValues, [this.fileObject])
-              .pipe(
-                take(1),
-                map((requestEntry: RequestEntry) => {
-                  if (requestEntry.response.isSuccessful) {
+          }
+        }),
+        getFirstCompletedRemoteData(),
+      ).subscribe((rd: RemoteData<Process>) => {
+        if (rd.hasSucceeded) {
           const title = this.translate.get('process.new.notification.success.title');
           const content = this.translate.get('process.new.notification.success.content');
           this.notificationsService.success(title, content);
-                    const response: any = requestEntry.response;
-                    if (isNotEmpty(response.resourceSelfLinks)) {
-                      const processNumber = response.resourceSelfLinks[0].split('/').pop();
-                      this.router.navigateByUrl('/processes/' + processNumber);
+          if (isNotEmpty(rd.payload)) {
+            this.router.navigateByUrl(getProcessDetailRoute(rd.payload.processId));
           }
         } else {
           const title = this.translate.get('process.new.notification.error.title');
           const content = this.translate.get('process.new.notification.error.content');
           this.notificationsService.error(title, content);
         }
-                }));
-          }
-        }),
-        take(1)
-      ).subscribe();
+      });
     }
   }
 }

src/app/+admin/admin-registries/bitstream-formats/add-bitstream-format/add-bitstream-format.component.spec.ts

@@ -6,7 +6,6 @@ import { RouterTestingModule } from '@angular/router/testing';
 import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateModule } from '@ngx-translate/core';
 import { of as observableOf } from 'rxjs';
-import { RestResponse } from '../../../../core/cache/response.models';
 import { BitstreamFormatDataService } from '../../../../core/data/bitstream-format-data.service';
 import { BitstreamFormatSupportLevel } from '../../../../core/shared/bitstream-format-support-level';
 import { BitstreamFormat } from '../../../../core/shared/bitstream-format.model';
@@ -14,6 +13,7 @@ import { NotificationsService } from '../../../../shared/notifications/notificat
 import { NotificationsServiceStub } from '../../../../shared/testing/notifications-service.stub';
 import { RouterStub } from '../../../../shared/testing/router.stub';
 import { AddBitstreamFormatComponent } from './add-bitstream-format.component';
+import { createFailedRemoteDataObject$, createSuccessfulRemoteDataObject$ } from '../../../../shared/remote-data.utils';
 
 describe('AddBitstreamFormatComponent', () => {
   let comp: AddBitstreamFormatComponent;
@@ -37,7 +37,7 @@ describe('AddBitstreamFormatComponent', () => {
     router = new RouterStub();
     notificationService = new NotificationsServiceStub();
     bitstreamFormatDataService = jasmine.createSpyObj('bitstreamFormatDataService', {
-      createBitstreamFormat: observableOf(new RestResponse(true, 200, 'Success')),
+      createBitstreamFormat: createSuccessfulRemoteDataObject$({}),
       clearBitStreamFormatRequests: observableOf(null)
     });
 
@@ -77,7 +77,7 @@ describe('AddBitstreamFormatComponent', () => {
       router = new RouterStub();
       notificationService = new NotificationsServiceStub();
       bitstreamFormatDataService = jasmine.createSpyObj('bitstreamFormatDataService', {
-        createBitstreamFormat: observableOf(new RestResponse(false, 400, 'Bad Request')),
+        createBitstreamFormat: createFailedRemoteDataObject$('Error', 500),
         clearBitStreamFormatRequests: observableOf(null)
       });
 

src/app/+admin/admin-registries/bitstream-formats/add-bitstream-format/add-bitstream-format.component.ts

@@ -1,12 +1,12 @@
-import { take } from 'rxjs/operators';
 import { Router } from '@angular/router';
 import { Component } from '@angular/core';
 import { BitstreamFormat } from '../../../../core/shared/bitstream-format.model';
 import { BitstreamFormatDataService } from '../../../../core/data/bitstream-format-data.service';
-import { RestResponse } from '../../../../core/cache/response.models';
 import { NotificationsService } from '../../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
 import { getBitstreamFormatsModuleRoute } from '../../admin-registries-routing-paths';
+import { RemoteData } from '../../../../core/data/remote-data';
+import { getFirstCompletedRemoteData } from '../../../../core/shared/operators';
 
 /**
  * This component renders the page to create a new bitstream format.
@@ -32,9 +32,10 @@ export class AddBitstreamFormatComponent {
    * @param bitstreamFormat
    */
   createBitstreamFormat(bitstreamFormat: BitstreamFormat) {
-    this.bitstreamFormatDataService.createBitstreamFormat(bitstreamFormat).pipe(take(1)
-    ).subscribe((response: RestResponse) => {
-        if (response.isSuccessful) {
+    this.bitstreamFormatDataService.createBitstreamFormat(bitstreamFormat).pipe(
+      getFirstCompletedRemoteData(),
+    ).subscribe((response: RemoteData<BitstreamFormat>) => {
+        if (response.hasSucceeded) {
           this.notificationService.success(this.translateService.get('admin.registries.bitstream-formats.create.success.head'),
             this.translateService.get('admin.registries.bitstream-formats.create.success.content'));
           this.router.navigate([getBitstreamFormatsModuleRoute()]);

src/app/+admin/admin-registries/bitstream-formats/bitstream-formats.component.spec.ts

@@ -1,8 +1,6 @@
 import { BitstreamFormatsComponent } from './bitstream-formats.component';
 import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { of as observableOf } from 'rxjs';
-import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
 import { CommonModule } from '@angular/common';
 import { RouterTestingModule } from '@angular/router/testing';
 import { TranslateModule } from '@ngx-translate/core';
@@ -19,6 +17,12 @@ import { BitstreamFormat } from '../../../core/shared/bitstream-format.model';
 import { BitstreamFormatSupportLevel } from '../../../core/shared/bitstream-format-support-level';
 import { cold, getTestScheduler, hot } from 'jasmine-marbles';
 import { TestScheduler } from 'rxjs/testing';
+import {
+  createNoContentRemoteDataObject$,
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 describe('BitstreamFormatsComponent', () => {
   let comp: BitstreamFormatsComponent;
@@ -73,7 +77,7 @@ describe('BitstreamFormatsComponent', () => {
     bitstreamFormat3,
     bitstreamFormat4
   ];
-  const mockFormatsRD = new RemoteData(false, false, true, undefined, new PaginatedList(null, mockFormatsList));
+  const mockFormatsRD = createSuccessfulRemoteDataObject(createPaginatedList(mockFormatsList));
 
   const initAsync = () => {
     notificationsServiceStub = new NotificationsServiceStub();
@@ -82,12 +86,12 @@ describe('BitstreamFormatsComponent', () => {
 
     bitstreamFormatService = jasmine.createSpyObj('bitstreamFormatService', {
       findAll: observableOf(mockFormatsRD),
-      find: observableOf(new RemoteData(false, false, true, undefined, mockFormatsList[0])),
+      find: createSuccessfulRemoteDataObject$(mockFormatsList[0]),
       getSelectedBitstreamFormats: hot('a', {a: mockFormatsList}),
       selectBitstreamFormat: {},
       deselectBitstreamFormat: {},
       deselectAllBitstreamFormats: {},
-      delete: observableOf(true),
+      delete: createSuccessfulRemoteDataObject$({}),
       clearBitStreamFormatRequests: observableOf('cleared')
     });
 
@@ -204,12 +208,12 @@ describe('BitstreamFormatsComponent', () => {
 
         bitstreamFormatService = jasmine.createSpyObj('bitstreamFormatService', {
           findAll: observableOf(mockFormatsRD),
-          find: observableOf(new RemoteData(false, false, true, undefined, mockFormatsList[0])),
+          find: createSuccessfulRemoteDataObject$(mockFormatsList[0]),
           getSelectedBitstreamFormats: observableOf(mockFormatsList),
           selectBitstreamFormat: {},
           deselectBitstreamFormat: {},
           deselectAllBitstreamFormats: {},
-          delete: observableOf({ isSuccessful: true }),
+          delete: createNoContentRemoteDataObject$(),
           clearBitStreamFormatRequests: observableOf('cleared')
         });
 
@@ -250,7 +254,7 @@ describe('BitstreamFormatsComponent', () => {
 
         bitstreamFormatService = jasmine.createSpyObj('bitstreamFormatService', {
           findAll: observableOf(mockFormatsRD),
-          find: observableOf(new RemoteData(false, false, true, undefined, mockFormatsList[0])),
+          find: createSuccessfulRemoteDataObject$(mockFormatsList[0]),
           getSelectedBitstreamFormats: observableOf(mockFormatsList),
           selectBitstreamFormat: {},
           deselectBitstreamFormat: {},

src/app/+admin/admin-registries/bitstream-formats/bitstream-formats.component.ts

@@ -1,7 +1,7 @@
 import { Component, OnInit } from '@angular/core';
 import { BehaviorSubject, combineLatest as observableCombineLatest, Observable, zip } from 'rxjs';
 import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { PaginationComponentOptions } from '../../../shared/pagination/pagination-component-options.model';
 import { BitstreamFormat } from '../../../core/shared/bitstream-format.model';
 import { BitstreamFormatDataService } from '../../../core/data/bitstream-format-data.service';
@@ -11,7 +11,7 @@ import { hasValue } from '../../../shared/empty.util';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
-import { RestResponse } from '../../../core/cache/response.models';
+import { NoContent } from '../../../core/shared/NoContent.model';
 
 /**
  * This component renders a list of bitstream formats
@@ -65,7 +65,7 @@ export class BitstreamFormatsComponent implements OnInit {
         const tasks$ = [];
         for (const format of formats) {
           if (hasValue(format.id)) {
-            tasks$.push(this.bitstreamFormatService.delete(format.id).pipe(map((response: RestResponse) => response.isSuccessful)));
+            tasks$.push(this.bitstreamFormatService.delete(format.id).pipe(map((response: RemoteData<NoContent>) => response.hasSucceeded)));
           }
         }
         zip(...tasks$).subscribe((results: boolean[]) => {

src/app/+admin/admin-registries/bitstream-formats/bitstream-formats.resolver.ts

@@ -1,11 +1,10 @@
 import { Injectable } from '@angular/core';
 import { ActivatedRouteSnapshot, Resolve, RouterStateSnapshot } from '@angular/router';
 import { Observable } from 'rxjs';
-import { find } from 'rxjs/operators';
 import { RemoteData } from '../../../core/data/remote-data';
 import { BitstreamFormat } from '../../../core/shared/bitstream-format.model';
 import { BitstreamFormatDataService } from '../../../core/data/bitstream-format-data.service';
-import { hasValue } from '../../../shared/empty.util';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 
 /**
  * This class represents a resolver that requests a specific bitstreamFormat before the route is activated
@@ -25,7 +24,7 @@ export class BitstreamFormatsResolver implements Resolve<RemoteData<BitstreamFor
   resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<RemoteData<BitstreamFormat>> {
     return this.bitstreamFormatDataService.findById(route.params.id)
       .pipe(
-        find((RD) => hasValue(RD.error) || RD.hasSucceeded),
+        getFirstCompletedRemoteData()
       );
   }
 }

src/app/+admin/admin-registries/bitstream-formats/edit-bitstream-format/edit-bitstream-format.component.spec.ts

@@ -6,7 +6,6 @@ import { RouterTestingModule } from '@angular/router/testing';
 import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateModule } from '@ngx-translate/core';
 import { of as observableOf } from 'rxjs';
-import { RestResponse } from '../../../../core/cache/response.models';
 import { BitstreamFormatDataService } from '../../../../core/data/bitstream-format-data.service';
 import { RemoteData } from '../../../../core/data/remote-data';
 import { BitstreamFormatSupportLevel } from '../../../../core/shared/bitstream-format-support-level';
@@ -15,6 +14,11 @@ import { NotificationsService } from '../../../../shared/notifications/notificat
 import { NotificationsServiceStub } from '../../../../shared/testing/notifications-service.stub';
 import { RouterStub } from '../../../../shared/testing/router.stub';
 import { EditBitstreamFormatComponent } from './edit-bitstream-format.component';
+import {
+  createFailedRemoteDataObject$,
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../../shared/remote-data.utils';
 
 describe('EditBitstreamFormatComponent', () => {
   let comp: EditBitstreamFormatComponent;
@@ -32,7 +36,7 @@ describe('EditBitstreamFormatComponent', () => {
 
   const routeStub = {
     data: observableOf({
-      bitstreamFormat: new RemoteData(false, false, true, null, bitstreamFormat)
+      bitstreamFormat: createSuccessfulRemoteDataObject(bitstreamFormat)
     })
   };
 
@@ -44,7 +48,7 @@ describe('EditBitstreamFormatComponent', () => {
     router =  new RouterStub();
     notificationService = new NotificationsServiceStub();
     bitstreamFormatDataService = jasmine.createSpyObj('bitstreamFormatDataService', {
-      updateBitstreamFormat: observableOf(new RestResponse(true, 200, 'Success'))
+      updateBitstreamFormat: createSuccessfulRemoteDataObject$({})
     });
 
     TestBed.configureTestingModule({
@@ -73,7 +77,8 @@ describe('EditBitstreamFormatComponent', () => {
     it('should initialise the bitstreamFormat based on the route', () => {
 
       comp.bitstreamFormatRD$.subscribe((format: RemoteData<BitstreamFormat>) => {
-        expect(format).toEqual(new RemoteData(false, false, true, null, bitstreamFormat));
+        const expected = createSuccessfulRemoteDataObject(bitstreamFormat);
+        expect(format.payload).toEqual(expected.payload);
       });
     });
   });
@@ -94,7 +99,7 @@ describe('EditBitstreamFormatComponent', () => {
       router =  new RouterStub();
       notificationService = new NotificationsServiceStub();
       bitstreamFormatDataService = jasmine.createSpyObj('bitstreamFormatDataService', {
-        updateBitstreamFormat: observableOf(new RestResponse(false, 400, 'Bad Request'))
+        updateBitstreamFormat: createFailedRemoteDataObject$('Error', 500)
       });
 
       TestBed.configureTestingModule({

src/app/+admin/admin-registries/bitstream-formats/edit-bitstream-format/edit-bitstream-format.component.ts

@@ -1,14 +1,14 @@
-import { map, take } from 'rxjs/operators';
+import { map } from 'rxjs/operators';
 import { ActivatedRoute, Router } from '@angular/router';
 import { Observable } from 'rxjs';
 import { Component, OnInit } from '@angular/core';
 import { RemoteData } from '../../../../core/data/remote-data';
 import { BitstreamFormat } from '../../../../core/shared/bitstream-format.model';
 import { BitstreamFormatDataService } from '../../../../core/data/bitstream-format-data.service';
-import { RestResponse } from '../../../../core/cache/response.models';
 import { NotificationsService } from '../../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
 import { getBitstreamFormatsModuleRoute } from '../../admin-registries-routing-paths';
+import { getFirstCompletedRemoteData } from '../../../../core/shared/operators';
 
 /**
  * This component renders the edit page of a bitstream format.
@@ -46,9 +46,10 @@ export class EditBitstreamFormatComponent implements OnInit {
    * When failed, an error  notification will be shown.
    */
   updateFormat(bitstreamFormat: BitstreamFormat) {
-    this.bitstreamFormatDataService.updateBitstreamFormat(bitstreamFormat).pipe(take(1)
-    ).subscribe((response: RestResponse) => {
-        if (response.isSuccessful) {
+    this.bitstreamFormatDataService.updateBitstreamFormat(bitstreamFormat).pipe(
+      getFirstCompletedRemoteData(),
+    ).subscribe((response: RemoteData<BitstreamFormat>) => {
+        if (response.hasSucceeded) {
           this.notificationService.success(this.translateService.get('admin.registries.bitstream-formats.edit.success.head'),
             this.translateService.get('admin.registries.bitstream-formats.edit.success.content'));
           this.router.navigate([getBitstreamFormatsModuleRoute()]);

src/app/+admin/admin-registries/metadata-registry/metadata-registry.component.spec.ts

@@ -1,7 +1,7 @@
 import { MetadataRegistryComponent } from './metadata-registry.component';
 import { async, ComponentFixture, inject, TestBed } from '@angular/core/testing';
 import { of as observableOf } from 'rxjs';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { TranslateModule } from '@ngx-translate/core';
 import { By } from '@angular/platform-browser';
 import { CommonModule } from '@angular/common';
@@ -45,7 +45,7 @@ describe('MetadataRegistryComponent', () => {
       namespace: 'http://dspace.org/mockschema'
     }
   ];
-  const mockSchemas = createSuccessfulRemoteDataObject$(new PaginatedList(null, mockSchemasList));
+  const mockSchemas = createSuccessfulRemoteDataObject$(buildPaginatedList(null, mockSchemasList));
   /* tslint:disable:no-empty */
   const registryServiceStub = {
     getMetadataSchemas: () => mockSchemas,

src/app/+admin/admin-registries/metadata-registry/metadata-registry.component.ts

@@ -2,18 +2,19 @@ import { Component } from '@angular/core';
 import { RegistryService } from '../../../core/registry/registry.service';
 import { Observable, combineLatest as observableCombineLatest } from 'rxjs';
 import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { PaginationComponentOptions } from '../../../shared/pagination/pagination-component-options.model';
 import { filter, map, switchMap, take } from 'rxjs/operators';
 import { hasValue } from '../../../shared/empty.util';
-import { RestResponse } from '../../../core/cache/response.models';
 import { zip } from 'rxjs/internal/observable/zip';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
-import { Route, Router } from '@angular/router';
+import { Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
 import { MetadataSchema } from '../../../core/metadata/metadata-schema.model';
 import { toFindListOptions } from '../../../shared/pagination/pagination.utils';
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
+import { NoContent } from '../../../core/shared/NoContent.model';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 
 @Component({
   selector: 'ds-metadata-registry',
@@ -140,12 +141,12 @@ export class MetadataRegistryComponent {
         const tasks$ = [];
         for (const schema of schemas) {
           if (hasValue(schema.id)) {
-            tasks$.push(this.registryService.deleteMetadataSchema(schema.id));
+            tasks$.push(this.registryService.deleteMetadataSchema(schema.id).pipe(getFirstCompletedRemoteData()));
           }
         }
-        zip(...tasks$).subscribe((responses: RestResponse[]) => {
-          const successResponses = responses.filter((response: RestResponse) => response.isSuccessful);
-          const failedResponses = responses.filter((response: RestResponse) => !response.isSuccessful);
+        zip(...tasks$).subscribe((responses: Array<RemoteData<NoContent>>) => {
+          const successResponses = responses.filter((response: RemoteData<NoContent>) => response.hasSucceeded);
+          const failedResponses = responses.filter((response: RemoteData<NoContent>) => response.hasFailed);
           if (successResponses.length > 0) {
             this.showNotification(true, successResponses.length);
           }

src/app/+admin/admin-registries/metadata-schema/metadata-schema.component.spec.ts

@@ -1,7 +1,7 @@
 import { MetadataSchemaComponent } from './metadata-schema.component';
 import { async, ComponentFixture, inject, TestBed } from '@angular/core/testing';
 import { of as observableOf } from 'rxjs';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { TranslateModule } from '@ngx-translate/core';
 import { CommonModule } from '@angular/common';
 import { ActivatedRoute, Router } from '@angular/router';
@@ -100,11 +100,11 @@ describe('MetadataSchemaComponent', () => {
       schema: createSuccessfulRemoteDataObject$(mockSchemasList[1])
     }
   ];
-  const mockSchemas = createSuccessfulRemoteDataObject$(new PaginatedList(null, mockSchemasList));
+  const mockSchemas = createSuccessfulRemoteDataObject$(buildPaginatedList(null, mockSchemasList));
   /* tslint:disable:no-empty */
   const registryServiceStub = {
     getMetadataSchemas: () => mockSchemas,
-    getMetadataFieldsBySchema: (schema: MetadataSchema) => createSuccessfulRemoteDataObject$(new PaginatedList(null, mockFieldsList.filter((value) => value.id === 3 || value.id === 4))),
+    getMetadataFieldsBySchema: (schema: MetadataSchema) => createSuccessfulRemoteDataObject$(buildPaginatedList(null, mockFieldsList.filter((value) => value.id === 3 || value.id === 4))),
     getMetadataSchemaByPrefix: (schemaName: string) => createSuccessfulRemoteDataObject$(mockSchemasList.filter((value) => value.prefix === schemaName)[0]),
     getActiveMetadataField: () => observableOf(undefined),
     getSelectedMetadataFields: () => observableOf([]),

src/app/+admin/admin-registries/metadata-schema/metadata-schema.component.ts

@@ -3,21 +3,24 @@ import { RegistryService } from '../../../core/registry/registry.service';
 import { ActivatedRoute, Router } from '@angular/router';
 import { Observable, combineLatest as observableCombineLatest } from 'rxjs';
 import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { PaginationComponentOptions } from '../../../shared/pagination/pagination-component-options.model';
 import { map, switchMap, take } from 'rxjs/operators';
 import { hasValue } from '../../../shared/empty.util';
-import { RestResponse } from '../../../core/cache/response.models';
 import { zip } from 'rxjs/internal/observable/zip';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
 import { MetadataField } from '../../../core/metadata/metadata-field.model';
 import { MetadataSchema } from '../../../core/metadata/metadata-schema.model';
-import { getFirstSucceededRemoteDataPayload } from '../../../core/shared/operators';
+import {
+  getFirstSucceededRemoteDataPayload,
+  getFirstCompletedRemoteData
+} from '../../../core/shared/operators';
 import { toFindListOptions } from '../../../shared/pagination/pagination.utils';
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
 import { combineLatest } from 'rxjs/internal/observable/combineLatest';
 import { followLink } from '../../../shared/utils/follow-link-config.model';
+import { NoContent } from '../../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-metadata-schema',
@@ -92,7 +95,7 @@ export class MetadataSchemaComponent implements OnInit {
     this.metadataFields$ = combineLatest(this.metadataSchema$, this.needsUpdate$).pipe(
       switchMap(([schema, update]: [MetadataSchema, boolean]) => {
         if (update) {
-          return this.registryService.getMetadataFieldsBySchema(schema, toFindListOptions(this.config), followLink('schema'));
+          return this.registryService.getMetadataFieldsBySchema(schema, toFindListOptions(this.config), true, followLink('schema'));
         }
       })
     );
@@ -168,12 +171,12 @@ export class MetadataSchemaComponent implements OnInit {
         const tasks$ = [];
         for (const field of fields) {
           if (hasValue(field.id)) {
-            tasks$.push(this.registryService.deleteMetadataField(field.id));
+            tasks$.push(this.registryService.deleteMetadataField(field.id).pipe(getFirstCompletedRemoteData()));
           }
         }
-        zip(...tasks$).subscribe((responses: RestResponse[]) => {
-          const successResponses = responses.filter((response: RestResponse) => response.isSuccessful);
-          const failedResponses = responses.filter((response: RestResponse) => !response.isSuccessful);
+        zip(...tasks$).subscribe((responses: Array<RemoteData<NoContent>>) => {
+          const successResponses = responses.filter((response: RemoteData<NoContent>) => response.hasSucceeded);
+          const failedResponses = responses.filter((response: RemoteData<NoContent>) => response.hasFailed);
           if (successResponses.length > 0) {
             this.showNotification(true, successResponses.length);
           }

src/app/+bitstream-page/bitstream-page.resolver.ts

@@ -2,11 +2,10 @@ import { Injectable } from '@angular/core';
 import { ActivatedRouteSnapshot, Resolve, RouterStateSnapshot } from '@angular/router';
 import { RemoteData } from '../core/data/remote-data';
 import { Observable } from 'rxjs/internal/Observable';
-import { find } from 'rxjs/operators';
-import { hasValue } from '../shared/empty.util';
 import { Bitstream } from '../core/shared/bitstream.model';
 import { BitstreamDataService } from '../core/data/bitstream-data.service';
 import {followLink, FollowLinkConfig} from '../shared/utils/follow-link-config.model';
+import { getFirstCompletedRemoteData } from '../core/shared/operators';
 
 /**
  * This class represents a resolver that requests a specific bitstream before the route is activated
@@ -24,9 +23,9 @@ export class BitstreamPageResolver implements Resolve<RemoteData<Bitstream>> {
    * or an error if something went wrong
    */
   resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<RemoteData<Bitstream>> {
-    return this.bitstreamService.findById(route.params.id, ...this.followLinks)
+    return this.bitstreamService.findById(route.params.id, false, ...this.followLinks)
       .pipe(
-        find((RD) => hasValue(RD.error) || RD.hasSucceeded),
+        getFirstCompletedRemoteData(),
       );
   }
     /**

src/app/+bitstream-page/edit-bitstream-page/edit-bitstream-page.component.spec.ts

@@ -2,7 +2,6 @@ import { EditBitstreamPageComponent } from './edit-bitstream-page.component';
 import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { TranslateModule } from '@ngx-translate/core';
 import { RouterTestingModule } from '@angular/router/testing';
-import { RemoteData } from '../../core/data/remote-data';
 import { of as observableOf } from 'rxjs/internal/observable/of';
 import {ActivatedRoute, Router} from '@angular/router';
 import { DynamicFormControlModel, DynamicFormService } from '@ng-dynamic-forms/core';
@@ -17,16 +16,15 @@ import { BitstreamFormat } from '../../core/shared/bitstream-format.model';
 import { BitstreamFormatSupportLevel } from '../../core/shared/bitstream-format-support-level';
 import { hasValue } from '../../shared/empty.util';
 import { FormControl, FormGroup } from '@angular/forms';
-import { PaginatedList } from '../../core/data/paginated-list';
-import { PageInfo } from '../../core/shared/page-info.model';
 import { FileSizePipe } from '../../shared/utils/file-size-pipe';
-import { RestResponse } from '../../core/cache/response.models';
 import { VarDirective } from '../../shared/utils/var.directive';
 import {
+  createSuccessfulRemoteDataObject,
   createSuccessfulRemoteDataObject$
 } from '../../shared/remote-data.utils';
 import {RouterStub} from '../../shared/testing/router.stub';
 import { getItemEditRoute } from '../../+item-page/item-page-routing-paths';
+import { createPaginatedList } from '../../shared/testing/utils.test';
 
 const infoNotification: INotification = new Notification('id', NotificationType.Info, 'info');
 const warningNotification: INotification = new Notification('id', NotificationType.Warning, 'warning');
@@ -109,7 +107,7 @@ describe('EditBitstreamPageComponent', () => {
           }
         ]
       },
-      format: observableOf(new RemoteData(false, false, true, null, selectedFormat)),
+      format: createSuccessfulRemoteDataObject$(selectedFormat),
       _links: {
         self: 'bitstream-selflink'
       },
@@ -120,14 +118,14 @@ describe('EditBitstreamPageComponent', () => {
       })
     });
     bitstreamService = jasmine.createSpyObj('bitstreamService', {
-      findById: observableOf(new RemoteData(false, false, true, null, bitstream)),
-      update: observableOf(new RemoteData(false, false, true, null, bitstream)),
-      updateFormat: observableOf(new RestResponse(true, 200, 'OK')),
+      findById: createSuccessfulRemoteDataObject$(bitstream),
+      update: createSuccessfulRemoteDataObject$(bitstream),
+      updateFormat: createSuccessfulRemoteDataObject$(bitstream),
       commitUpdates: {},
       patch: {}
     });
     bitstreamFormatService = jasmine.createSpyObj('bitstreamFormatService', {
-      findAll: observableOf(new RemoteData(false, false, true, null, new PaginatedList(new PageInfo(), allFormats)))
+      findAll: createSuccessfulRemoteDataObject$(createPaginatedList(allFormats))
     });
 
     const itemPageUrl = `fake-url/some-uuid`;
@@ -140,7 +138,7 @@ describe('EditBitstreamPageComponent', () => {
       providers: [
         { provide: NotificationsService, useValue: notificationsService },
         { provide: DynamicFormService, useValue: formService },
-        { provide: ActivatedRoute, useValue: { data: observableOf({ bitstream: new RemoteData(false, false, true, null, bitstream) }), snapshot: { queryParams: {} } } },
+        { provide: ActivatedRoute, useValue: { data: observableOf({ bitstream: createSuccessfulRemoteDataObject(bitstream) }), snapshot: { queryParams: {} } } },
         { provide: BitstreamDataService, useValue: bitstreamService },
         { provide: BitstreamFormatDataService, useValue: bitstreamFormatService },
         { provide: Router, useValue: routerStub },

src/app/+bitstream-page/edit-bitstream-page/edit-bitstream-page.component.ts

@@ -22,19 +22,19 @@ import {
   getAllSucceededRemoteDataPayload,
   getFirstSucceededRemoteDataPayload,
   getRemoteDataPayload,
-  getSucceededRemoteData
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
 } from '../../core/shared/operators';
 import { NotificationsService } from '../../shared/notifications/notifications.service';
 import { BitstreamFormatDataService } from '../../core/data/bitstream-format-data.service';
 import { BitstreamFormat } from '../../core/shared/bitstream-format.model';
 import { BitstreamFormatSupportLevel } from '../../core/shared/bitstream-format-support-level';
-import { RestResponse } from '../../core/cache/response.models';
 import { hasValue, isNotEmpty } from '../../shared/empty.util';
 import { Metadata } from '../../core/shared/metadata.utils';
 import { Location } from '@angular/common';
 import { Observable } from 'rxjs/internal/Observable';
 import { RemoteData } from '../../core/data/remote-data';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList } from '../../core/data/paginated-list.model';
 import { getItemEditRoute } from '../../+item-page/item-page-routing-paths';
 import { Bundle } from '../../core/shared/bundle.model';
 import { Item } from '../../core/shared/item.model';
@@ -299,12 +299,12 @@ export class EditBitstreamPageComponent implements OnInit, OnDestroy {
     this.bitstreamFormatsRD$ = this.bitstreamFormatService.findAll(this.findAllOptions);
 
     const bitstream$ = this.bitstreamRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload()
     );
 
     const allFormats$ = this.bitstreamFormatsRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload()
     );
 
@@ -438,16 +438,15 @@ export class EditBitstreamPageComponent implements OnInit, OnDestroy {
 
     if (isNewFormat) {
       bitstream$ = this.bitstreamService.updateFormat(this.bitstream, selectedFormat).pipe(
-        switchMap((formatResponse: RestResponse) => {
-          if (hasValue(formatResponse) && !formatResponse.isSuccessful) {
+        getFirstCompletedRemoteData(),
+        map((formatResponse: RemoteData<Bitstream>) => {
+          if (hasValue(formatResponse) && formatResponse.hasFailed) {
             this.notificationsService.error(
               this.translate.instant(this.NOTIFICATIONS_PREFIX + 'error.format.title'),
-              formatResponse.statusText
+              formatResponse.errorMessage
             );
           } else {
-            return this.bitstreamService.findById(this.bitstream.id).pipe(
-              getFirstSucceededRemoteDataPayload()
-            );
+            return formatResponse.payload;
           }
         })
       );

src/app/+browse-by/+browse-by-date-page/browse-by-date-page.component.ts

@@ -1,4 +1,4 @@
-import { ChangeDetectorRef, Component, Inject } from '@angular/core';
+import { ChangeDetectorRef, Component } from '@angular/core';
 import {
   BrowseByMetadataPageComponent,
   browseParamsToOptions
@@ -43,7 +43,7 @@ export class BrowseByDatePageComponent extends BrowseByMetadataPageComponent {
 
   ngOnInit(): void {
     this.startsWithType = StartsWithType.date;
-    this.updatePage(new BrowseEntrySearchOptions(null, this.paginationConfig, this.sortConfig));
+    this.updatePage(new BrowseEntrySearchOptions(this.defaultBrowseId, this.paginationConfig, this.sortConfig));
     this.subs.push(
       observableCombineLatest(
         this.route.params,

src/app/+browse-by/+browse-by-metadata-page/browse-by-metadata-page.component.spec.ts

@@ -12,7 +12,7 @@ import { of as observableOf } from 'rxjs/internal/observable/of';
 import { NO_ERRORS_SCHEMA } from '@angular/core';
 import { Observable } from 'rxjs/internal/Observable';
 import { RemoteData } from '../../core/data/remote-data';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../core/data/paginated-list.model';
 import { PageInfo } from '../../core/shared/page-info.model';
 import { BrowseEntrySearchOptions } from '../../core/browse/browse-entry-search-options.model';
 import { SortDirection } from '../../core/cache/models/sort-options.model';
@@ -157,5 +157,5 @@ describe('BrowseByMetadataPageComponent', () => {
 });
 
 export function toRemoteData(objects: any[]): Observable<RemoteData<PaginatedList<any>>> {
-  return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), objects));
+  return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), objects));
 }

src/app/+browse-by/+browse-by-metadata-page/browse-by-metadata-page.component.ts

@@ -1,7 +1,7 @@
-import {combineLatest as observableCombineLatest, merge as observableMerge, Observable, Subscription } from 'rxjs';
+import { combineLatest as observableCombineLatest, Observable, Subscription } from 'rxjs';
 import { Component, OnInit } from '@angular/core';
 import { RemoteData } from '../../core/data/remote-data';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList } from '../../core/data/paginated-list.model';
 import { PaginationComponentOptions } from '../../shared/pagination/pagination-component-options.model';
 import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
 import { ActivatedRoute, Router } from '@angular/router';
@@ -10,10 +10,9 @@ import { BrowseService } from '../../core/browse/browse.service';
 import { BrowseEntry } from '../../core/shared/browse-entry.model';
 import { Item } from '../../core/shared/item.model';
 import { BrowseEntrySearchOptions } from '../../core/browse/browse-entry-search-options.model';
-import { getSucceededRemoteData } from '../../core/shared/operators';
+import { getFirstSucceededRemoteData } from '../../core/shared/operators';
 import { DSpaceObjectDataService } from '../../core/data/dspace-object-data.service';
 import { DSpaceObject } from '../../core/shared/dspace-object.model';
-import { take } from 'rxjs/operators';
 import { StartsWithType } from '../../shared/starts-with/starts-with-decorator';
 import { BrowseByType, rendersBrowseBy } from '../+browse-by-switcher/browse-by-decorator';
 
@@ -105,7 +104,7 @@ export class BrowseByMetadataPageComponent implements OnInit {
   }
 
   ngOnInit(): void {
-    this.updatePage(new BrowseEntrySearchOptions(null, this.paginationConfig, this.sortConfig));
+    this.updatePage(new BrowseEntrySearchOptions(this.defaultBrowseId, this.paginationConfig, this.sortConfig));
     this.subs.push(
       observableCombineLatest(
         this.route.params,
@@ -169,7 +168,7 @@ export class BrowseByMetadataPageComponent implements OnInit {
   updateParent(scope: string) {
     if (hasValue(scope)) {
       this.parent$ = this.dsoService.findById(scope).pipe(
-        getSucceededRemoteData()
+        getFirstSucceededRemoteData()
       );
     }
   }
@@ -179,11 +178,11 @@ export class BrowseByMetadataPageComponent implements OnInit {
    */
   goPrev() {
     if (this.items$) {
-      this.items$.pipe(take(1)).subscribe((items) => {
+      this.items$.pipe(getFirstSucceededRemoteData()).subscribe((items) => {
         this.items$ = this.browseService.getPrevBrowseItems(items);
       });
     } else if (this.browseEntries$) {
-      this.browseEntries$.pipe(take(1)).subscribe((entries) => {
+      this.browseEntries$.pipe(getFirstSucceededRemoteData()).subscribe((entries) => {
         this.browseEntries$ = this.browseService.getPrevBrowseEntries(entries);
       });
     }
@@ -194,11 +193,11 @@ export class BrowseByMetadataPageComponent implements OnInit {
    */
   goNext() {
     if (this.items$) {
-      this.items$.pipe(take(1)).subscribe((items) => {
+      this.items$.pipe(getFirstSucceededRemoteData()).subscribe((items) => {
         this.items$ = this.browseService.getNextBrowseItems(items);
       });
     } else if (this.browseEntries$) {
-      this.browseEntries$.pipe(take(1)).subscribe((entries) => {
+      this.browseEntries$.pipe(getFirstSucceededRemoteData()).subscribe((entries) => {
         this.browseEntries$ = this.browseService.getNextBrowseEntries(entries);
       });
     }

src/app/+browse-by/+browse-by-title-page/browse-by-title-page.component.ts

@@ -32,7 +32,7 @@ export class BrowseByTitlePageComponent extends BrowseByMetadataPageComponent {
 
   ngOnInit(): void {
     this.sortConfig = new SortOptions('dc.title', SortDirection.ASC);
-    this.updatePage(new BrowseEntrySearchOptions(null, this.paginationConfig, this.sortConfig));
+    this.updatePage(new BrowseEntrySearchOptions(this.defaultBrowseId, this.paginationConfig, this.sortConfig));
     this.subs.push(
       observableCombineLatest(
         this.route.params,

src/app/+browse-by/browse-by-dso-breadcrumb.resolver.ts

@@ -6,7 +6,7 @@ import { Collection } from '../core/shared/collection.model';
 import { ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
 import { BreadcrumbConfig } from '../breadcrumbs/breadcrumb/breadcrumb-config.model';
 import { Observable } from 'rxjs';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../core/shared/operators';
 import { map } from 'rxjs/operators';
 import { hasValue } from '../shared/empty.util';
 import { getDSORoute } from '../app-routing-paths';
@@ -29,7 +29,7 @@ export class BrowseByDSOBreadcrumbResolver {
     const uuid = route.queryParams.scope;
     if (hasValue(uuid)) {
       return this.dataService.findById(uuid).pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
         map((object: Community | Collection) => {
           return { provider: this.breadcrumbService, key: object, url: getDSORoute(object) };

src/app/+browse-by/browse-by-guard.ts

@@ -3,7 +3,7 @@ import { Inject, Injectable } from '@angular/core';
 import { DSpaceObjectDataService } from '../core/data/dspace-object-data.service';
 import { hasNoValue, hasValue } from '../shared/empty.util';
 import { map } from 'rxjs/operators';
-import { getSucceededRemoteData } from '../core/shared/operators';
+import { getFirstSucceededRemoteData } from '../core/shared/operators';
 import { TranslateService } from '@ngx-translate/core';
 import { of as observableOf } from 'rxjs';
 import { environment } from '../../environments/environment';
@@ -32,7 +32,7 @@ export class BrowseByGuard implements CanActivate {
     const value = route.queryParams.value;
     const metadataTranslated = this.translate.instant('browse.metadata.' + id);
     if (hasValue(scope)) {
-      const dsoAndMetadata$ = this.dsoService.findById(scope).pipe(getSucceededRemoteData());
+      const dsoAndMetadata$ = this.dsoService.findById(scope).pipe(getFirstSucceededRemoteData());
       return dsoAndMetadata$.pipe(
         map((dsoRD) => {
           const name = dsoRD.payload.name;

src/app/+collection-page/collection-item-mapper/collection-item-mapper.component.spec.ts

@@ -1,4 +1,3 @@
-import { filter, tap } from 'rxjs/operators';
 import { CollectionItemMapperComponent } from './collection-item-mapper.component';
 import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { RouterTestingModule } from '@angular/router/testing';
@@ -22,8 +21,6 @@ import { EventEmitter } from '@angular/core';
 import { HostWindowService } from '../../shared/host-window.service';
 import { HostWindowServiceStub } from '../../shared/testing/host-window-service.stub';
 import { By } from '@angular/platform-browser';
-import { PaginatedList } from '../../core/data/paginated-list';
-import { PageInfo } from '../../core/shared/page-info.model';
 import { CollectionDataService } from '../../core/data/collection-data.service';
 import { PaginationComponent } from '../../shared/pagination/pagination.component';
 import { EnumKeysPipe } from '../../shared/utils/enum-keys-pipe';
@@ -39,6 +36,12 @@ import { LoadingComponent } from '../../shared/loading/loading.component';
 import { SearchConfigurationService } from '../../core/shared/search/search-configuration.service';
 import { SearchService } from '../../core/shared/search/search.service';
 import { PaginatedSearchOptions } from '../../shared/search/paginated-search-options.model';
+import {
+  createFailedRemoteDataObject$,
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../shared/remote-data.utils';
+import { createPaginatedList } from '../../shared/testing/utils.test';
 
 describe('CollectionItemMapperComponent', () => {
   let comp: CollectionItemMapperComponent;
@@ -60,7 +63,7 @@ describe('CollectionItemMapperComponent', () => {
       }
     }
   });
-  const mockCollectionRD: RemoteData<Collection> = new RemoteData<Collection>(false, false, true, null, mockCollection);
+  const mockCollectionRD: RemoteData<Collection> = createSuccessfulRemoteDataObject(mockCollection);
   const mockSearchOptions = of(new PaginatedSearchOptions({
     pagination: Object.assign(new PaginationComponentOptions(), {
       id: 'search-page-configuration',
@@ -81,7 +84,7 @@ describe('CollectionItemMapperComponent', () => {
     paginatedSearchOptions: mockSearchOptions
   };
   const itemDataServiceStub = {
-    mapToCollection: () => of(new RestResponse(true, 200, 'OK'))
+    mapToCollection: () => createSuccessfulRemoteDataObject$({})
   };
   const activatedRouteStub = new ActivatedRouteStub({}, { dso: mockCollectionRD });
   const translateServiceStub = {
@@ -90,7 +93,7 @@ describe('CollectionItemMapperComponent', () => {
     onTranslationChange: new EventEmitter(),
     onDefaultLangChange: new EventEmitter()
   };
-  const emptyList = new RemoteData(false, false, true, null, new PaginatedList(new PageInfo(), []));
+  const emptyList = createSuccessfulRemoteDataObject(createPaginatedList([]));
   const searchServiceStub = Object.assign(new SearchServiceStub(), {
     search: () => of(emptyList),
     /* tslint:disable:no-empty */
@@ -167,7 +170,7 @@ describe('CollectionItemMapperComponent', () => {
     });
 
     it('should display an error message if at least one mapping was unsuccessful', () => {
-      spyOn(itemDataService, 'mapToCollection').and.returnValue(of(new RestResponse(false, 404, 'Not Found')));
+      spyOn(itemDataService, 'mapToCollection').and.returnValue(createFailedRemoteDataObject$('Not Found', 404));
       comp.mapItems(ids);
       expect(notificationsService.success).not.toHaveBeenCalled();
       expect(notificationsService.error).toHaveBeenCalled();

src/app/+collection-page/collection-item-mapper/collection-item-mapper.component.ts

@@ -5,9 +5,13 @@ import { fadeIn, fadeInOut } from '../../shared/animations/fade';
 import { ActivatedRoute, Router } from '@angular/router';
 import { RemoteData } from '../../core/data/remote-data';
 import { Collection } from '../../core/shared/collection.model';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList } from '../../core/data/paginated-list.model';
 import { map, startWith, switchMap, take } from 'rxjs/operators';
-import { getRemoteDataPayload, getSucceededRemoteData, toDSpaceObjectListRD } from '../../core/shared/operators';
+import {
+  getRemoteDataPayload,
+  getFirstSucceededRemoteData,
+  toDSpaceObjectListRD
+} from '../../core/shared/operators';
 import { DSpaceObject } from '../../core/shared/dspace-object.model';
 import { DSpaceObjectType } from '../../core/shared/dspace-object-type.model';
 import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
@@ -16,13 +20,13 @@ import { ItemDataService } from '../../core/data/item-data.service';
 import { TranslateService } from '@ngx-translate/core';
 import { CollectionDataService } from '../../core/data/collection-data.service';
 import { isNotEmpty } from '../../shared/empty.util';
-import { RestResponse } from '../../core/cache/response.models';
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
 import { SEARCH_CONFIG_SERVICE } from '../../+my-dspace-page/my-dspace-page.component';
 import { SearchConfigurationService } from '../../core/shared/search/search-configuration.service';
 import { PaginatedSearchOptions } from '../../shared/search/paginated-search-options.model';
 import { SearchService } from '../../core/shared/search/search.service';
 import { followLink } from '../../shared/utils/follow-link-config.model';
+import { NoContent } from '../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-collection-item-mapper',
@@ -102,7 +106,7 @@ export class CollectionItemMapperComponent implements OnInit {
   }
 
   ngOnInit(): void {
-    this.collectionRD$ = this.route.data.pipe(map((data) => data.dso)).pipe(getSucceededRemoteData()) as Observable<RemoteData<Collection>>;
+    this.collectionRD$ = this.route.data.pipe(map((data) => data.dso)).pipe(getFirstSucceededRemoteData()) as Observable<RemoteData<Collection>>;
     this.searchOptions$ = this.searchConfigService.paginatedSearchOptions;
     this.loadItemLists();
   }
@@ -151,7 +155,7 @@ export class CollectionItemMapperComponent implements OnInit {
    */
   mapItems(ids: string[], remove?: boolean) {
     const responses$ = this.collectionRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       map((collectionRD: RemoteData<Collection>) => collectionRD.payload),
       switchMap((collection: Collection) =>
         observableCombineLatest(ids.map((id: string) =>
@@ -168,12 +172,12 @@ export class CollectionItemMapperComponent implements OnInit {
    * @param {Observable<RestResponse[]>} responses$   The responses after adding/removing a mapping
    * @param {boolean} remove                          Whether or not the goal was to remove mappings
    */
-  private showNotifications(responses$: Observable<RestResponse[]>, remove?: boolean) {
+  private showNotifications(responses$: Observable<Array<RemoteData<NoContent>>>, remove?: boolean) {
     const messageInsertion = remove ? 'unmap' : 'map';
 
-    responses$.subscribe((responses: RestResponse[]) => {
-      const successful = responses.filter((response: RestResponse) => response.isSuccessful);
-      const unsuccessful = responses.filter((response: RestResponse) => !response.isSuccessful);
+    responses$.subscribe((responses: Array<RemoteData<NoContent>>) => {
+      const successful = responses.filter((response: RemoteData<any>) => response.hasSucceeded);
+      const unsuccessful = responses.filter((response: RemoteData<any>) => response.hasFailed);
       if (successful.length > 0) {
         const successMessages = observableCombineLatest(
           this.translateService.get(`collection.edit.item-mapper.notifications.${messageInsertion}.success.head`),
@@ -246,7 +250,7 @@ export class CollectionItemMapperComponent implements OnInit {
    */
   onCancel() {
     this.collectionRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       take(1)
     ).subscribe((collection: Collection) => {

src/app/+collection-page/collection-page.component.ts

@@ -1,12 +1,12 @@
 import { ChangeDetectionStrategy, Component, OnInit } from '@angular/core';
 import { ActivatedRoute, Router } from '@angular/router';
-import { BehaviorSubject, of as observableOf, Observable, Subject } from 'rxjs';
-import { filter, flatMap, map, startWith, switchMap, take, tap } from 'rxjs/operators';
+import { BehaviorSubject, Observable, Subject } from 'rxjs';
+import { filter, flatMap, map, startWith, switchMap, take } from 'rxjs/operators';
 import { PaginatedSearchOptions } from '../shared/search/paginated-search-options.model';
 import { SearchService } from '../core/shared/search/search.service';
 import { SortDirection, SortOptions } from '../core/cache/models/sort-options.model';
 import { CollectionDataService } from '../core/data/collection-data.service';
-import { PaginatedList } from '../core/data/paginated-list';
+import { PaginatedList } from '../core/data/paginated-list.model';
 import { RemoteData } from '../core/data/remote-data';
 
 import { MetadataService } from '../core/metadata/metadata.service';
@@ -16,13 +16,13 @@ import { Collection } from '../core/shared/collection.model';
 import { DSpaceObjectType } from '../core/shared/dspace-object-type.model';
 import { Item } from '../core/shared/item.model';
 import {
-  getSucceededRemoteData,
+  getFirstSucceededRemoteData,
   redirectOn4xx,
   toDSpaceObjectListRD
 } from '../core/shared/operators';
 
 import { fadeIn, fadeInOut } from '../shared/animations/fade';
-import { hasNoValue, hasValue, isNotEmpty } from '../shared/empty.util';
+import { hasValue, isNotEmpty } from '../shared/empty.util';
 import { PaginationComponentOptions } from '../shared/pagination/pagination-component-options.model';
 import { AuthService } from '../core/auth/auth.service';
 
@@ -81,7 +81,7 @@ export class CollectionPageComponent implements OnInit {
 
     this.itemRD$ = this.paginationChanges$.pipe(
       switchMap((dto) => this.collectionRD$.pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         map((rd) => rd.payload.id),
         switchMap((id: string) => {
           return this.searchService.search(

src/app/+collection-page/collection-page.resolver.spec.ts

@@ -1,6 +1,6 @@
 import { first } from 'rxjs/operators';
-import { of as observableOf } from 'rxjs';
 import { CollectionPageResolver } from './collection-page.resolver';
+import { createSuccessfulRemoteDataObject$ } from '../shared/remote-data.utils';
 
 describe('CollectionPageResolver', () => {
   describe('resolve', () => {
@@ -10,17 +10,18 @@ describe('CollectionPageResolver', () => {
 
     beforeEach(() => {
       collectionService = {
-        findById: (id: string) => observableOf({ payload: { id }, hasSucceeded: true })
+        findById: (id: string) => createSuccessfulRemoteDataObject$({ id })
       };
       resolver = new CollectionPageResolver(collectionService);
     });
 
-    it('should resolve a collection with the correct id', () => {
+    it('should resolve a collection with the correct id', (done) => {
       resolver.resolve({ params: { id: uuid } } as any, undefined)
         .pipe(first())
         .subscribe(
           (resolved) => {
             expect(resolved.payload.id).toEqual(uuid);
+            done();
           }
         );
     });

src/app/+collection-page/collection-page.resolver.ts

@@ -4,9 +4,8 @@ import { Collection } from '../core/shared/collection.model';
 import { Observable } from 'rxjs';
 import { CollectionDataService } from '../core/data/collection-data.service';
 import { RemoteData } from '../core/data/remote-data';
-import { find } from 'rxjs/operators';
-import { hasValue } from '../shared/empty.util';
 import { followLink } from '../shared/utils/follow-link-config.model';
+import { getFirstCompletedRemoteData } from '../core/shared/operators';
 
 /**
  * This class represents a resolver that requests a specific collection before the route is activated
@@ -24,8 +23,8 @@ export class CollectionPageResolver implements Resolve<RemoteData<Collection>> {
    * or an error if something went wrong
    */
   resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<RemoteData<Collection>> {
-    return this.collectionService.findById(route.params.id, followLink('logo')).pipe(
-      find((RD) => hasValue(RD.error) || RD.hasSucceeded),
+    return this.collectionService.findById(route.params.id, false, followLink('logo')).pipe(
+      getFirstCompletedRemoteData()
     );
   }
 }

src/app/+collection-page/create-collection-page/create-collection-page.guard.spec.ts

@@ -18,7 +18,7 @@ describe('CreateCollectionPageGuard', () => {
           } else if (id === 'invalid-id') {
             return createSuccessfulRemoteDataObject$(undefined);
           } else if (id === 'error-id') {
-            return createFailedRemoteDataObject$(new Community());
+            return createFailedRemoteDataObject$('not found', 404);
           }
         }
       };

src/app/+collection-page/create-collection-page/create-collection-page.guard.ts

@@ -5,8 +5,9 @@ import { hasNoValue, hasValue } from '../../shared/empty.util';
 import { CommunityDataService } from '../../core/data/community-data.service';
 import { RemoteData } from '../../core/data/remote-data';
 import { Community } from '../../core/shared/community.model';
-import { map, tap, find } from 'rxjs/operators';
+import { map, tap } from 'rxjs/operators';
 import { Observable, of as observableOf } from 'rxjs';
+import { getFirstCompletedRemoteData } from '../../core/shared/operators';
 
 /**
  * Prevent creation of a collection without a parent community provided
@@ -30,7 +31,7 @@ export class CreateCollectionPageGuard implements CanActivate {
     }
     return this.communityService.findById(parentID)
       .pipe(
-        find((communityRD: RemoteData<Community>) => hasValue(communityRD.payload) || hasValue(communityRD.error)),
+        getFirstCompletedRemoteData(),
         map((communityRD: RemoteData<Community>) => hasValue(communityRD) && communityRD.hasSucceeded && hasValue(communityRD.payload)),
         tap((isValid: boolean) => {
           if (!isValid) {

src/app/+collection-page/edit-collection-page/collection-metadata/collection-metadata.component.ts

@@ -7,7 +7,7 @@ import { ItemTemplateDataService } from '../../../core/data/item-template-data.s
 import { Observable } from 'rxjs/internal/Observable';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Item } from '../../../core/shared/item.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../core/shared/operators';
 import { switchMap, take } from 'rxjs/operators';
 import { combineLatest as combineLatestObservable } from 'rxjs';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
@@ -54,7 +54,7 @@ export class CollectionMetadataComponent extends ComcolMetadataComponent<Collect
    */
   initTemplateItem() {
     this.itemTemplateRD$ = this.dsoRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       switchMap((collection: Collection) => this.itemTemplateService.findByCollectionID(collection.uuid))
     );
@@ -65,13 +65,13 @@ export class CollectionMetadataComponent extends ComcolMetadataComponent<Collect
    */
   addItemTemplate() {
     const collection$ = this.dsoRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       take(1)
     );
     const template$ = collection$.pipe(
       switchMap((collection: Collection) => this.itemTemplateService.create(new Item(), collection.uuid)),
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       take(1)
     );
@@ -86,13 +86,13 @@ export class CollectionMetadataComponent extends ComcolMetadataComponent<Collect
    */
   deleteItemTemplate() {
     const collection$ = this.dsoRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       take(1)
     );
     const template$ = collection$.pipe(
       switchMap((collection: Collection) => this.itemTemplateService.findByCollectionID(collection.uuid)),
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       take(1)
     );

src/app/+collection-page/edit-collection-page/collection-roles/collection-roles.component.html

@@ -1,5 +1,5 @@
 <ds-comcol-role
-  *ngFor="let comcolRole of getComcolRoles() | async"
+  *ngFor="let comcolRole of comcolRoles$ | async"
   [dso]="collection$ | async"
   [comcolRole]="comcolRole"
 >

src/app/+collection-page/edit-collection-page/collection-roles/collection-roles.component.spec.ts

@@ -11,6 +11,7 @@ import { SharedModule } from '../../../shared/shared.module';
 import { GroupDataService } from '../../../core/eperson/group-data.service';
 import { RequestService } from '../../../core/data/request.service';
 import { RouterTestingModule } from '@angular/router/testing';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
 
 describe('CollectionRolesComponent', () => {
 
@@ -23,11 +24,7 @@ describe('CollectionRolesComponent', () => {
     const route = {
       parent: {
         data: observableOf({
-          dso: new RemoteData(
-            false,
-            false,
-            true,
-            undefined,
+          dso: createSuccessfulRemoteDataObject(
             Object.assign(new Collection(), {
               _links: {
                 irrelevant: {
@@ -52,25 +49,18 @@ describe('CollectionRolesComponent', () => {
                   },
                 ],
               },
-            }),
+            })
           ),
         })
       }
     };
 
     const requestService = {
-      hasByHrefObservable: () => observableOf(true),
+      hasByHref$: () => observableOf(true),
     };
 
     const groupDataService = {
-      findByHref: () => observableOf(new RemoteData(
-        false,
-        false,
-        true,
-        undefined,
-        {},
-        200,
-      )),
+      findByHref: () => createSuccessfulRemoteDataObject$({}),
     };
 
     TestBed.configureTestingModule({

src/app/+collection-page/edit-collection-page/collection-roles/collection-roles.component.ts

@@ -4,7 +4,7 @@ import { Observable } from 'rxjs';
 import { first, map } from 'rxjs/operators';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Collection } from '../../../core/shared/collection.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../core/shared/operators';
 import { HALLink } from '../../../core/shared/hal-link.model';
 
 /**
@@ -18,21 +18,33 @@ export class CollectionRolesComponent implements OnInit {
 
   dsoRD$: Observable<RemoteData<Collection>>;
 
-  /**
-   * The collection to manage, as an observable.
-   */
-  get collection$(): Observable<Collection> {
-    return this.dsoRD$.pipe(
-      getSucceededRemoteData(),
-      getRemoteDataPayload(),
-    )
-  }
-
   /**
    * The different roles for the collection, as an observable.
    */
-  getComcolRoles(): Observable<HALLink[]> {
-    return this.collection$.pipe(
+  comcolRoles$: Observable<HALLink[]>
+
+  /**
+   * The collection to manage, as an observable.
+   */
+  collection$: Observable<Collection>
+
+  constructor(
+    protected route: ActivatedRoute,
+  ) {
+  }
+
+  ngOnInit(): void {
+    this.dsoRD$ = this.route.parent.data.pipe(
+      first(),
+      map((data) => data.dso),
+    );
+
+    this.collection$ = this.dsoRD$.pipe(
+      getFirstSucceededRemoteData(),
+      getRemoteDataPayload(),
+    );
+
+    this.comcolRoles$ = this.collection$.pipe(
       map((collection) => [
         {
           name: 'collection-admin',
@@ -54,16 +66,4 @@ export class CollectionRolesComponent implements OnInit {
       ]),
     );
   }
-
-  constructor(
-    protected route: ActivatedRoute,
-  ) {
-  }
-
-  ngOnInit(): void {
-    this.dsoRD$ = this.route.parent.data.pipe(
-      first(),
-      map((data) => data.dso),
-    );
-  }
 }

src/app/+collection-page/edit-collection-page/collection-source/collection-source.component.spec.ts

@@ -17,9 +17,9 @@ import { FormControl, FormGroup } from '@angular/forms';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { By } from '@angular/platform-browser';
 import { Collection } from '../../../core/shared/collection.model';
-import { RemoteData } from '../../../core/data/remote-data';
 import { CollectionDataService } from '../../../core/data/collection-data.service';
 import { RequestService } from '../../../core/data/request.service';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
 
 const infoNotification: INotification = new Notification('id', NotificationType.Info, 'info');
 const warningNotification: INotification = new Notification('id', NotificationType.Warning, 'warning');
@@ -111,7 +111,7 @@ describe('CollectionSourceComponent', () => {
       uuid: 'fake-collection-id'
     });
     collectionService = jasmine.createSpyObj('collectionService', {
-      getContentSource: observableOf(contentSource),
+      getContentSource: createSuccessfulRemoteDataObject$(contentSource),
       updateContentSource: observableOf(contentSource),
       getHarvesterEndpoint: observableOf('harvester-endpoint')
     });
@@ -125,7 +125,7 @@ describe('CollectionSourceComponent', () => {
         { provide: NotificationsService, useValue: notificationsService },
         { provide: Location, useValue: location },
         { provide: DynamicFormService, useValue: formService },
-        { provide: ActivatedRoute, useValue: { parent: { data: observableOf({ dso: new RemoteData(false, false, true, null, collection) }) } } },
+        { provide: ActivatedRoute, useValue: { parent: { data: observableOf({ dso: createSuccessfulRemoteDataObject(collection) }) } } },
         { provide: Router, useValue: router },
         { provide: CollectionDataService, useValue: collectionService },
         { provide: RequestService, useValue: requestService }

src/app/+collection-page/edit-collection-page/collection-source/collection-source.component.ts

@@ -27,7 +27,7 @@ import { FieldUpdate, FieldUpdates } from '../../../core/data/object-updates/obj
 import { Subscription } from 'rxjs/internal/Subscription';
 import { cloneDeep } from 'lodash';
 import { CollectionDataService } from '../../../core/data/collection-data.service';
-import { getSucceededRemoteData } from '../../../core/shared/operators';
+import { getFirstSucceededRemoteData, getFirstCompletedRemoteData } from '../../../core/shared/operators';
 import { MetadataConfig } from '../../../core/shared/metadata-config.model';
 import { INotification } from '../../../shared/notifications/models/notification.model';
 import { RequestService } from '../../../core/data/request.service';
@@ -255,12 +255,12 @@ export class CollectionSourceComponent extends AbstractTrackableComponent implem
     this.collectionRD$ = this.route.parent.data.pipe(first(), map((data) => data.dso));
 
     this.collectionRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       map((col) => col.payload.uuid),
       switchMap((uuid) => this.collectionService.getContentSource(uuid)),
-      take(1)
-    ).subscribe((contentSource: ContentSource) => {
-      this.initializeOriginalContentSource(contentSource);
+      getFirstCompletedRemoteData(),
+    ).subscribe((rd: RemoteData<ContentSource>) => {
+      this.initializeOriginalContentSource(rd.payload);
     });
 
     this.updateFieldTranslations();
@@ -376,7 +376,7 @@ export class CollectionSourceComponent extends AbstractTrackableComponent implem
   onSubmit() {
     // Remove cached harvester request to allow for latest harvester to be displayed when switching tabs
     this.collectionRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       map((col) => col.payload.uuid),
       switchMap((uuid) => this.collectionService.getHarvesterEndpoint(uuid)),
       take(1)
@@ -384,7 +384,7 @@ export class CollectionSourceComponent extends AbstractTrackableComponent implem
 
     // Update harvester
     this.collectionRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       map((col) => col.payload.uuid),
       switchMap((uuid) => this.collectionService.updateContentSource(uuid, this.contentSource)),
       take(1)

src/app/+collection-page/edit-item-template-page/item-template-page.resolver.spec.ts

@@ -1,6 +1,6 @@
-import { of as observableOf } from 'rxjs/internal/observable/of';
 import { first } from 'rxjs/operators';
 import { ItemTemplatePageResolver } from './item-template-page.resolver';
+import { createSuccessfulRemoteDataObject$ } from '../../shared/remote-data.utils';
 
 describe('ItemTemplatePageResolver', () => {
   describe('resolve', () => {
@@ -10,17 +10,18 @@ describe('ItemTemplatePageResolver', () => {
 
     beforeEach(() => {
       itemTemplateService = {
-        findByCollectionID: (id: string) => observableOf({ payload: { id }, hasSucceeded: true })
+        findByCollectionID: (id: string) => createSuccessfulRemoteDataObject$({ id })
       };
       resolver = new ItemTemplatePageResolver(itemTemplateService);
     });
 
-    it('should resolve an item template with the correct id', () => {
+    it('should resolve an item template with the correct id', (done) => {
       resolver.resolve({ params: { id: uuid } } as any, undefined)
         .pipe(first())
         .subscribe(
           (resolved) => {
             expect(resolved.payload.id).toEqual(uuid);
+            done();
           }
         );
     });

src/app/+collection-page/edit-item-template-page/item-template-page.resolver.ts

@@ -4,9 +4,8 @@ import { RemoteData } from '../../core/data/remote-data';
 import { Item } from '../../core/shared/item.model';
 import { ItemTemplateDataService } from '../../core/data/item-template-data.service';
 import { Observable } from 'rxjs/internal/Observable';
-import { find } from 'rxjs/operators';
-import { hasValue } from '../../shared/empty.util';
 import { followLink } from '../../shared/utils/follow-link-config.model';
+import { getFirstCompletedRemoteData } from '../../core/shared/operators';
 
 /**
  * This class represents a resolver that requests a specific collection's item template before the route is activated
@@ -24,8 +23,8 @@ export class ItemTemplatePageResolver implements Resolve<RemoteData<Item>> {
    * or an error if something went wrong
    */
   resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<RemoteData<Item>> {
-    return this.itemTemplateService.findByCollectionID(route.params.id, followLink('templateItemOf')).pipe(
-      find((RD) => hasValue(RD.error) || RD.hasSucceeded),
+    return this.itemTemplateService.findByCollectionID(route.params.id, false, followLink('templateItemOf')).pipe(
+      getFirstCompletedRemoteData(),
     );
   }
 }

src/app/+community-page/community-page.component.ts

@@ -1,8 +1,8 @@
 import { mergeMap, filter, map } from 'rxjs/operators';
-import { ChangeDetectionStrategy, Component, OnDestroy, OnInit } from '@angular/core';
+import { ChangeDetectionStrategy, Component, OnInit } from '@angular/core';
 import { ActivatedRoute, Router } from '@angular/router';
 
-import { Subscription, Observable } from 'rxjs';
+import { Observable } from 'rxjs';
 import { CommunityDataService } from '../core/data/community-data.service';
 import { RemoteData } from '../core/data/remote-data';
 import { Bitstream } from '../core/shared/bitstream.model';

src/app/+community-page/community-page.resolver.spec.ts

@@ -1,6 +1,6 @@
-import { of as observableOf } from 'rxjs';
 import { first } from 'rxjs/operators';
 import { CommunityPageResolver } from './community-page.resolver';
+import { createSuccessfulRemoteDataObject$ } from '../shared/remote-data.utils';
 
 describe('CommunityPageResolver', () => {
   describe('resolve', () => {
@@ -10,17 +10,18 @@ describe('CommunityPageResolver', () => {
 
     beforeEach(() => {
       communityService = {
-        findById: (id: string) => observableOf({ payload: { id }, hasSucceeded: true })
+        findById: (id: string) => createSuccessfulRemoteDataObject$({ id })
       };
       resolver = new CommunityPageResolver(communityService);
     });
 
-    it('should resolve a community with the correct id', () => {
+    it('should resolve a community with the correct id', (done) => {
       resolver.resolve({ params: { id: uuid } } as any, undefined)
         .pipe(first())
         .subscribe(
           (resolved) => {
             expect(resolved.payload.id).toEqual(uuid);
+            done();
           }
         );
     });

src/app/+community-page/community-page.resolver.ts

@@ -4,9 +4,8 @@ import { Observable } from 'rxjs';
 import { RemoteData } from '../core/data/remote-data';
 import { Community } from '../core/shared/community.model';
 import { CommunityDataService } from '../core/data/community-data.service';
-import { find } from 'rxjs/operators';
-import { hasValue } from '../shared/empty.util';
 import { followLink } from '../shared/utils/follow-link-config.model';
+import { getFirstCompletedRemoteData } from '../core/shared/operators';
 
 /**
  * This class represents a resolver that requests a specific community before the route is activated
@@ -26,11 +25,12 @@ export class CommunityPageResolver implements Resolve<RemoteData<Community>> {
   resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<RemoteData<Community>> {
     return this.communityService.findById(
       route.params.id,
+      false,
       followLink('logo'),
       followLink('subcommunities'),
       followLink('collections')
     ).pipe(
-      find((RD) => hasValue(RD.error) || RD.hasSucceeded)
+      getFirstCompletedRemoteData(),
     );
   }
 }

src/app/+community-page/create-community-page/create-community-page.guard.spec.ts

@@ -2,7 +2,10 @@ import { CreateCommunityPageGuard } from './create-community-page.guard';
 import { RouterMock } from '../../shared/mocks/router.mock';
 import { Community } from '../../core/shared/community.model';
 import { first } from 'rxjs/operators';
-import { createFailedRemoteDataObject$, createSuccessfulRemoteDataObject$ } from '../../shared/remote-data.utils';
+import {
+  createFailedRemoteDataObject$,
+  createSuccessfulRemoteDataObject$
+} from '../../shared/remote-data.utils';
 
 describe('CreateCommunityPageGuard', () => {
   describe('canActivate', () => {
@@ -18,7 +21,7 @@ describe('CreateCommunityPageGuard', () => {
           } else if (id === 'invalid-id') {
             return createSuccessfulRemoteDataObject$(undefined);
           } else if (id === 'error-id') {
-            return createFailedRemoteDataObject$(new Community());
+            return createFailedRemoteDataObject$('not found', 404);
           }
         }
       };

src/app/+community-page/create-community-page/create-community-page.guard.ts

@@ -5,8 +5,9 @@ import { hasNoValue, hasValue } from '../../shared/empty.util';
 import { CommunityDataService } from '../../core/data/community-data.service';
 import { RemoteData } from '../../core/data/remote-data';
 import { Community } from '../../core/shared/community.model';
-import { map, tap, find } from 'rxjs/operators';
+import { map, tap } from 'rxjs/operators';
 import { Observable, of as observableOf } from 'rxjs';
+import { getFirstCompletedRemoteData } from '../../core/shared/operators';
 
 /**
  * Prevent creation of a community with an invalid parent community provided
@@ -30,7 +31,7 @@ export class CreateCommunityPageGuard implements CanActivate {
 
     return this.communityService.findById(parentID)
       .pipe(
-        find((communityRD: RemoteData<Community>) => hasValue(communityRD.payload) || hasValue(communityRD.error)),
+        getFirstCompletedRemoteData(),
         map((communityRD: RemoteData<Community>) => hasValue(communityRD) && communityRD.hasSucceeded && hasValue(communityRD.payload)),
         tap((isValid: boolean) => {
           if (!isValid) {

src/app/+community-page/edit-community-page/community-roles/community-roles.component.spec.ts

@@ -11,6 +11,7 @@ import { RequestService } from '../../../core/data/request.service';
 import { GroupDataService } from '../../../core/eperson/group-data.service';
 import { SharedModule } from '../../../shared/shared.module';
 import { RouterTestingModule } from '@angular/router/testing';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
 
 describe('CommunityRolesComponent', () => {
 
@@ -23,11 +24,7 @@ describe('CommunityRolesComponent', () => {
     const route = {
       parent: {
         data: observableOf({
-          dso: new RemoteData(
-            false,
-            false,
-            true,
-            undefined,
+          dso: createSuccessfulRemoteDataObject(
             Object.assign(new Community(), {
               _links: {
                 irrelevant: {
@@ -37,25 +34,18 @@ describe('CommunityRolesComponent', () => {
                   href: 'adminGroup link',
                 },
               },
-            }),
+            })
           ),
         })
       }
     };
 
     const requestService = {
-      hasByHrefObservable: () => observableOf(true),
+      hasByHref$: () => observableOf(true),
     };
 
     const groupDataService = {
-      findByHref: () => observableOf(new RemoteData(
-        false,
-        false,
-        true,
-        undefined,
-        {},
-        200,
-      )),
+      findByHref: () => createSuccessfulRemoteDataObject$({}),
     };
 
     TestBed.configureTestingModule({

src/app/+community-page/edit-community-page/community-roles/community-roles.component.ts

@@ -3,7 +3,7 @@ import { ActivatedRoute } from '@angular/router';
 import { Observable } from 'rxjs';
 import { first, map } from 'rxjs/operators';
 import { Community } from '../../../core/shared/community.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../core/shared/operators';
 import { RemoteData } from '../../../core/data/remote-data';
 import { HALLink } from '../../../core/shared/hal-link.model';
 
@@ -23,7 +23,7 @@ export class CommunityRolesComponent implements OnInit {
    */
   get community$(): Observable<Community> {
     return this.dsoRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
     )
   }

src/app/+community-page/sub-collection-list/community-page-sub-collection-list.component.spec.ts

@@ -13,7 +13,7 @@ import { SharedModule } from '../../shared/shared.module';
 import { CollectionDataService } from '../../core/data/collection-data.service';
 import { FindListOptions } from '../../core/data/request.models';
 import { createSuccessfulRemoteDataObject$ } from '../../shared/remote-data.utils';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { buildPaginatedList } from '../../core/data/paginated-list.model';
 import { PageInfo } from '../../core/shared/page-info.model';
 import { HostWindowService } from '../../shared/host-window.service';
 import { HostWindowServiceStub } from '../../shared/testing/host-window-service.stub';
@@ -105,7 +105,7 @@ describe('CommunityPageSubCollectionList Component', () => {
       if (endPageIndex > subCollList.length) {
         endPageIndex = subCollList.length;
       }
-      return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), subCollList.slice(startPageIndex, endPageIndex)));
+      return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), subCollList.slice(startPageIndex, endPageIndex)));
 
     }
   };

src/app/+community-page/sub-collection-list/community-page-sub-collection-list.component.ts

@@ -1,16 +1,16 @@
 import { Component, Input, OnInit } from '@angular/core';
 
 import { BehaviorSubject } from 'rxjs';
-import { take } from 'rxjs/operators';
 
 import { RemoteData } from '../../core/data/remote-data';
 import { Collection } from '../../core/shared/collection.model';
 import { Community } from '../../core/shared/community.model';
 import { fadeIn } from '../../shared/animations/fade';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList } from '../../core/data/paginated-list.model';
 import { PaginationComponentOptions } from '../../shared/pagination/pagination-component-options.model';
 import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
 import { CollectionDataService } from '../../core/data/collection-data.service';
+import { takeUntilCompletedRemoteData } from '../../core/shared/operators';
 
 @Component({
   selector: 'ds-community-page-sub-collection-list',
@@ -72,7 +72,7 @@ export class CommunityPageSubCollectionListComponent implements OnInit {
       currentPage: this.config.currentPage,
       elementsPerPage: this.config.pageSize,
       sort: { field: this.sortConfig.field, direction: this.sortConfig.direction }
-    }).pipe(take(1)).subscribe((results) => {
+    }).pipe(takeUntilCompletedRemoteData()).subscribe((results) => {
       this.subCollectionsRDObs.next(results);
     });
   }

src/app/+community-page/sub-community-list/community-page-sub-community-list.component.spec.ts

@@ -9,7 +9,7 @@ import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 
 import { CommunityPageSubCommunityListComponent } from './community-page-sub-community-list.component';
 import { Community } from '../../core/shared/community.model';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../core/data/paginated-list.model';
 import { PageInfo } from '../../core/shared/page-info.model';
 import { SharedModule } from '../../shared/shared.module';
 import { createSuccessfulRemoteDataObject$ } from '../../shared/remote-data.utils';
@@ -106,7 +106,7 @@ describe('CommunityPageSubCommunityListComponent Component', () => {
       if (endPageIndex > subCommList.length) {
         endPageIndex = subCommList.length;
       }
-      return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), subCommList.slice(startPageIndex, endPageIndex)));
+      return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), subCommList.slice(startPageIndex, endPageIndex)));
 
     }
   };

src/app/+community-page/sub-community-list/community-page-sub-community-list.component.ts

@@ -1,15 +1,15 @@
 import { Component, Input, OnInit } from '@angular/core';
 
 import { BehaviorSubject } from 'rxjs';
-import { take } from 'rxjs/operators';
 
 import { RemoteData } from '../../core/data/remote-data';
 import { Community } from '../../core/shared/community.model';
 import { fadeIn } from '../../shared/animations/fade';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList } from '../../core/data/paginated-list.model';
 import { PaginationComponentOptions } from '../../shared/pagination/pagination-component-options.model';
 import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
 import { CommunityDataService } from '../../core/data/community-data.service';
+import { takeUntilCompletedRemoteData } from '../../core/shared/operators';
 
 @Component({
   selector: 'ds-community-page-sub-community-list',
@@ -75,7 +75,7 @@ export class CommunityPageSubCommunityListComponent implements OnInit {
       currentPage: this.config.currentPage,
       elementsPerPage: this.config.pageSize,
       sort: { field: this.sortConfig.field, direction: this.sortConfig.direction }
-    }).pipe(take(1)).subscribe((results) => {
+    }).pipe(takeUntilCompletedRemoteData()).subscribe((results) => {
       this.subCommunitiesRDObs.next(results);
     });
   }

src/app/+home-page/top-level-community-list/top-level-community-list.component.spec.ts

@@ -9,7 +9,7 @@ import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 
 import { TopLevelCommunityListComponent } from './top-level-community-list.component';
 import { Community } from '../../core/shared/community.model';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../core/data/paginated-list.model';
 import { PageInfo } from '../../core/shared/page-info.model';
 import { SharedModule } from '../../shared/shared.module';
 import { createSuccessfulRemoteDataObject$ } from '../../shared/remote-data.utils';
@@ -96,7 +96,7 @@ describe('TopLevelCommunityList Component', () => {
       if (endPageIndex > topCommList.length) {
         endPageIndex = topCommList.length;
       }
-      return createSuccessfulRemoteDataObject$(new PaginatedList(new PageInfo(), topCommList.slice(startPageIndex, endPageIndex)));
+      return createSuccessfulRemoteDataObject$(buildPaginatedList(new PageInfo(), topCommList.slice(startPageIndex, endPageIndex)));
 
     }
   };

src/app/+home-page/top-level-community-list/top-level-community-list.component.ts

@@ -1,15 +1,15 @@
-import { ChangeDetectionStrategy, Component, OnInit } from '@angular/core';
+import { ChangeDetectionStrategy, Component, OnInit, OnDestroy } from '@angular/core';
 
-import { BehaviorSubject } from 'rxjs';
-import { take } from 'rxjs/operators';
+import { BehaviorSubject, Subscription } from 'rxjs';
 
 import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
 import { CommunityDataService } from '../../core/data/community-data.service';
-import { PaginatedList } from '../../core/data/paginated-list';
+import { PaginatedList } from '../../core/data/paginated-list.model';
 import { RemoteData } from '../../core/data/remote-data';
 import { Community } from '../../core/shared/community.model';
 import { fadeInOut } from '../../shared/animations/fade';
 import { PaginationComponentOptions } from '../../shared/pagination/pagination-component-options.model';
+import { hasValue } from '../../shared/empty.util';
 
 /**
  * this component renders the Top-Level Community list
@@ -22,7 +22,7 @@ import { PaginationComponentOptions } from '../../shared/pagination/pagination-c
   animations: [fadeInOut]
 })
 
-export class TopLevelCommunityListComponent implements OnInit {
+export class TopLevelCommunityListComponent implements OnInit, OnDestroy {
   /**
    * A list of remote data objects of all top communities
    */
@@ -43,6 +43,11 @@ export class TopLevelCommunityListComponent implements OnInit {
    */
   sortConfig: SortOptions;
 
+  /**
+   * The subscription to the observable for the current page.
+   */
+  currentPageSubscription: Subscription;
+
   constructor(private cds: CommunityDataService) {
     this.config = new PaginationComponentOptions();
     this.config.id = this.pageId;
@@ -71,12 +76,29 @@ export class TopLevelCommunityListComponent implements OnInit {
    * Update the list of top communities
    */
   updatePage() {
-    this.cds.findTop({
+    this.unsubscribe();
+    this.currentPageSubscription = this.cds.findTop({
       currentPage: this.config.currentPage,
       elementsPerPage: this.config.pageSize,
       sort: { field: this.sortConfig.field, direction: this.sortConfig.direction }
-    }).pipe(take(1)).subscribe((results) => {
+    }).subscribe((results) => {
       this.communitiesRD$.next(results);
     });
   }
+
+  /**
+   * Unsubscribe the top list subscription if it exists
+   */
+  private unsubscribe() {
+    if (hasValue(this.currentPageSubscription)) {
+      this.currentPageSubscription.unsubscribe();
+    }
+  }
+
+  /**
+   * Clean up subscriptions when the component is destroyed
+   */
+  ngOnDestroy() {
+    this.unsubscribe();
+  }
 }

src/app/+item-page/bitstreams/upload/upload-bitstream.component.spec.ts

@@ -16,7 +16,10 @@ import { Bitstream } from '../../../core/shared/bitstream.model';
 import { BundleDataService } from '../../../core/data/bundle-data.service';
 import { Bundle } from '../../../core/shared/bundle.model';
 import { RequestService } from '../../../core/data/request.service';
-import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
+import {
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
 import { createPaginatedList } from '../../../shared/testing/utils.test';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { NotificationsServiceStub } from '../../../shared/testing/notifications-service.stub';
@@ -192,7 +195,7 @@ describe('UploadBistreamComponent', () => {
   function createUploadBitstreamTestingModule(queryParams) {
     routeStub = {
       data: observableOf({
-        item: createSuccessfulRemoteDataObject(mockItem)
+        dso: createSuccessfulRemoteDataObject(mockItem)
       }),
       queryParams: observableOf(queryParams),
       snapshot: {

src/app/+item-page/bitstreams/upload/upload-bitstream.component.ts

@@ -11,7 +11,7 @@ import { ItemDataService } from '../../../core/data/item-data.service';
 import { AuthService } from '../../../core/auth/auth.service';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { Bundle } from '../../../core/shared/bundle.model';
 import { BundleDataService } from '../../../core/data/bundle-data.service';
 import {
@@ -103,7 +103,7 @@ export class UploadBitstreamComponent implements OnInit, OnDestroy {
    */
   ngOnInit(): void {
     this.itemId = this.route.snapshot.params.id;
-    this.itemRD$ = this.route.data.pipe(map((data) => data.item));
+    this.itemRD$ = this.route.data.pipe(map((data) => data.dso));
     this.bundlesRD$ = this.itemRD$.pipe(
       switchMap((itemRD: RemoteData<Item>) => itemRD.payload.bundles)
     );

src/app/+item-page/edit-item-page/edit-item-operators.spec.ts

@@ -6,6 +6,7 @@ import {
   createFailedRemoteDataObject,
   createSuccessfulRemoteDataObject
 } from '../../shared/remote-data.utils';
+import { isNotEmpty } from '../../shared/empty.util';
 
 describe('findSuccessfulAccordingTo', () => {
   let mockItem1;
@@ -19,12 +20,12 @@ describe('findSuccessfulAccordingTo', () => {
     mockItem2 = new Item();
     mockItem1.isWithdrawn = false;
 
-    predicate = (rd: RemoteData<Item>) => rd.payload.isWithdrawn;
+    predicate = (rd: RemoteData<Item>) => isNotEmpty(rd.payload) ? rd.payload.isWithdrawn : false;
   });
   it('should return first successful RemoteData Observable that complies to predicate', () => {
     const testRD = {
       a: createSuccessfulRemoteDataObject(undefined),
-      b: createFailedRemoteDataObject(mockItem1),
+      b: createFailedRemoteDataObject(),
       c: createSuccessfulRemoteDataObject(mockItem2),
       d: createSuccessfulRemoteDataObject(mockItem1),
       e: createSuccessfulRemoteDataObject(mockItem2),

src/app/+item-page/edit-item-page/item-authorizations/item-authorizations.component.spec.ts

@@ -2,21 +2,18 @@ import { async, ComponentFixture, inject, TestBed } from '@angular/core/testing'
 import { Component, NO_ERRORS_SCHEMA } from '@angular/core';
 import { ActivatedRoute } from '@angular/router';
 import { NoopAnimationsModule } from '@angular/platform-browser/animations';
-
 import { of as observableOf } from 'rxjs';
 import { TranslateModule } from '@ngx-translate/core';
 import { cold } from 'jasmine-marbles';
-
 import { ItemAuthorizationsComponent } from './item-authorizations.component';
 import { Bitstream } from '../../../core/shared/bitstream.model';
 import { Bundle } from '../../../core/shared/bundle.model';
-import { createMockRDPaginatedObs } from '../item-bitstreams/item-bitstreams.component.spec';
 import { Item } from '../../../core/shared/item.model';
 import { LinkService } from '../../../core/cache/builders/link.service';
 import { getMockLinkService } from '../../../shared/mocks/link-service.mock';
-import { createSuccessfulRemoteDataObject } from '../../../shared/remote-data.utils';
-import { createTestComponent } from '../../../shared/testing/utils.test';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
+import { createPaginatedList, createTestComponent } from '../../../shared/testing/utils.test';
+import { PaginatedList, buildPaginatedList } from '../../../core/data/paginated-list.model';
 import { PageInfo } from '../../../core/shared/page-info.model';
 
 describe('ItemAuthorizationsComponent test suite', () => {
@@ -49,7 +46,7 @@ describe('ItemAuthorizationsComponent test suite', () => {
     _links: {
       self: { href: 'bundle1-selflink' }
     },
-    bitstreams: createMockRDPaginatedObs([bitstream1, bitstream2])
+    bitstreams: createSuccessfulRemoteDataObject$(createPaginatedList([bitstream1, bitstream2]))
   });
   const bundle2 = Object.assign(new Bundle(), {
     id: 'bundle2',
@@ -57,11 +54,11 @@ describe('ItemAuthorizationsComponent test suite', () => {
     _links: {
       self: { href: 'bundle2-selflink' }
     },
-    bitstreams: createMockRDPaginatedObs([bitstream3, bitstream4])
+    bitstreams: createSuccessfulRemoteDataObject$(createPaginatedList([bitstream3, bitstream4]))
   });
   const bundles = [bundle1, bundle2];
-  const bitstreamList1: PaginatedList<Bitstream> = new PaginatedList(new PageInfo(), [bitstream1, bitstream2]);
-  const bitstreamList2: PaginatedList<Bitstream> = new PaginatedList(new PageInfo(), [bitstream3, bitstream4]);
+  const bitstreamList1: PaginatedList<Bitstream> = buildPaginatedList(new PageInfo(), [bitstream1, bitstream2]);
+  const bitstreamList2: PaginatedList<Bitstream> = buildPaginatedList(new PageInfo(), [bitstream3, bitstream4]);
 
   const item = Object.assign(new Item(), {
     uuid: 'item',
@@ -69,7 +66,7 @@ describe('ItemAuthorizationsComponent test suite', () => {
     _links: {
       self: { href: 'item-selflink' }
     },
-    bundles: createMockRDPaginatedObs([bundle1, bundle2])
+    bundles: createSuccessfulRemoteDataObject$(createPaginatedList([bundle1, bundle2]))
   });
 
   const routeStub = {

src/app/+item-page/edit-item-page/item-authorizations/item-authorizations.component.ts

@@ -4,7 +4,7 @@ import { ActivatedRoute } from '@angular/router';
 import { BehaviorSubject, Observable, of as observableOf, Subscription } from 'rxjs';
 import { catchError, filter, first, flatMap, map, take } from 'rxjs/operators';
 
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../core/data/paginated-list.model';
 import {
   getFirstSucceededRemoteDataPayload,
   getFirstSucceededRemoteDataWithNotEmptyPayload
@@ -89,7 +89,7 @@ export class ItemAuthorizationsComponent implements OnInit, OnDestroy {
       getFirstSucceededRemoteDataWithNotEmptyPayload(),
       catchError((error) => {
         console.error(error);
-        return observableOf(new PaginatedList(null, []))
+        return observableOf(buildPaginatedList(null, []))
       })
     );
 
@@ -139,7 +139,7 @@ export class ItemAuthorizationsComponent implements OnInit, OnDestroy {
       getFirstSucceededRemoteDataPayload(),
       catchError((error) => {
         console.error(error);
-        return observableOf(new PaginatedList(null, []))
+        return observableOf(buildPaginatedList(null, []))
       })
     )
   }

src/app/+item-page/edit-item-page/item-bitstreams/item-bitstreams.component.spec.ts

@@ -1,8 +1,5 @@
 import { Bitstream } from '../../../core/shared/bitstream.model';
 import { of as observableOf } from 'rxjs/internal/observable/of';
-import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
-import { PageInfo } from '../../../core/shared/page-info.model';
 import { Item } from '../../../core/shared/item.model';
 import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { ItemBitstreamsComponent } from './item-bitstreams.component';
@@ -13,7 +10,10 @@ import { ActivatedRoute, Router } from '@angular/router';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { ChangeDetectorRef, NO_ERRORS_SCHEMA } from '@angular/core';
 import { FieldChangeType } from '../../../core/data/object-updates/object-updates.actions';
-import { INotification, Notification } from '../../../shared/notifications/models/notification.model';
+import {
+  INotification,
+  Notification
+} from '../../../shared/notifications/models/notification.model';
 import { NotificationType } from '../../../shared/notifications/models/notification-type';
 import { BitstreamDataService } from '../../../core/data/bitstream-data.service';
 import { ObjectCacheService } from '../../../core/cache/object-cache.service';
@@ -26,6 +26,11 @@ import { RestResponse } from '../../../core/cache/response.models';
 import { SearchConfigurationService } from '../../../core/shared/search/search-configuration.service';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { getMockRequestService } from '../../../shared/mocks/request.service.mock';
+import {
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 let comp: ItemBitstreamsComponent;
 let fixture: ComponentFixture<ItemBitstreamsComponent>;
@@ -55,7 +60,7 @@ const bundle = Object.assign(new Bundle(), {
   _links: {
     self: { href: 'bundle1-selflink' }
   },
-  bitstreams: createMockRDPaginatedObs([bitstream1, bitstream2])
+  bitstreams: createSuccessfulRemoteDataObject$(createPaginatedList([bitstream1, bitstream2]))
 });
 const moveOperations = [
   {
@@ -130,17 +135,17 @@ describe('ItemBitstreamsComponent', () => {
       _links: {
         self: { href: 'item-selflink' }
       },
-      bundles: createMockRDPaginatedObs([bundle]),
+      bundles: createSuccessfulRemoteDataObject$(createPaginatedList([bundle])),
       lastModified: date
     });
     itemService = Object.assign( {
-      getBitstreams: () => createMockRDPaginatedObs([bitstream1, bitstream2]),
-      findById: () => createMockRDObs(item),
-      getBundles: () => createMockRDPaginatedObs([bundle])
+      getBitstreams: () => createSuccessfulRemoteDataObject$(createPaginatedList([bitstream1, bitstream2])),
+      findById: () => createSuccessfulRemoteDataObject$(item),
+      getBundles: () => createSuccessfulRemoteDataObject$(createPaginatedList([bundle]))
     });
     route = Object.assign({
       parent: {
-        data: observableOf({ dso: createMockRD(item) })
+        data: observableOf({ dso: createSuccessfulRemoteDataObject(item) })
       },
       data: observableOf({}),
       url: url
@@ -235,15 +240,3 @@ describe('ItemBitstreamsComponent', () => {
     });
   });
 });
-
-export function createMockRDPaginatedObs(list: any[]) {
-  return createMockRDObs(new PaginatedList(new PageInfo(), list));
-}
-
-export function createMockRDObs(obj: any) {
-  return observableOf(createMockRD(obj));
-}
-
-export function createMockRD(obj: any) {
-  return new RemoteData(false, false, true, null, obj);
-}

src/app/+item-page/edit-item-page/item-bitstreams/item-bitstreams.component.ts

@@ -11,13 +11,12 @@ import { TranslateService } from '@ngx-translate/core';
 import { BitstreamDataService } from '../../../core/data/bitstream-data.service';
 import { hasValue, isNotEmpty } from '../../../shared/empty.util';
 import { zip as observableZip, of as observableOf } from 'rxjs';
-import { ErrorResponse, RestResponse } from '../../../core/cache/response.models';
 import { ObjectCacheService } from '../../../core/cache/object-cache.service';
 import { RequestService } from '../../../core/data/request.service';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../core/shared/operators';
 import { Item } from '../../../core/shared/item.model';
 import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { Bundle } from '../../../core/shared/bundle.model';
 import { FieldUpdate, FieldUpdates } from '../../../core/data/object-updates/object-updates.reducer';
 import { Bitstream } from '../../../core/shared/bitstream.model';
@@ -26,6 +25,8 @@ import { BundleDataService } from '../../../core/data/bundle-data.service';
 import { PaginatedSearchOptions } from '../../../shared/search/paginated-search-options.model';
 import { ResponsiveColumnSizes } from '../../../shared/responsive-table-sizes/responsive-column-sizes';
 import { ResponsiveTableSizes } from '../../../shared/responsive-table-sizes/responsive-table-sizes';
+import { NoContent } from '../../../core/shared/NoContent.model';
+import { Operation } from 'fast-json-patch';
 
 @Component({
   selector: 'ds-item-bitstreams',
@@ -107,7 +108,7 @@ export class ItemBitstreamsComponent extends AbstractItemUpdateComponent impleme
    */
   postItemInit(): void {
     this.bundles$ = this.itemService.getBundles(this.item.id, new PaginatedSearchOptions({pagination: this.bundlesOptions})).pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       map((bundlePage: PaginatedList<Bundle>) => bundlePage.page)
     );
@@ -125,10 +126,10 @@ export class ItemBitstreamsComponent extends AbstractItemUpdateComponent impleme
    * Also re-initialize the original fields and updates
    */
   initializeItemUpdate(): void {
-    this.itemUpdateSubscription = this.requestService.hasByHrefObservable(this.item.self).pipe(
+    this.itemUpdateSubscription = this.requestService.hasByHref$(this.item.self).pipe(
       filter((exists: boolean) => !exists),
       switchMap(() => this.itemService.findById(this.item.uuid)),
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
     ).subscribe((itemRD: RemoteData<Item>) => {
       if (hasValue(itemRD)) {
         this.item = itemRD.payload;
@@ -173,7 +174,7 @@ export class ItemBitstreamsComponent extends AbstractItemUpdateComponent impleme
     );
 
     // Perform the setup actions from above in order and display notifications
-    removedResponses$.pipe(take(1)).subscribe((responses: RestResponse[]) => {
+    removedResponses$.pipe(take(1)).subscribe((responses: Array<RemoteData<NoContent>>) => {
       this.displayNotifications('item.edit.bitstreams.notifications.remove', responses);
       this.reset();
       this.submitting = false;
@@ -190,12 +191,12 @@ export class ItemBitstreamsComponent extends AbstractItemUpdateComponent impleme
   dropBitstream(bundle: Bundle, event: any) {
     this.zone.runOutsideAngular(() => {
       if (hasValue(event) && hasValue(event.fromIndex) && hasValue(event.toIndex) && hasValue(event.finish)) {
-        const moveOperation = Object.assign({
+        const moveOperation = {
           op: 'move',
           from: `/_links/bitstreams/${event.fromIndex}/href`,
           path: `/_links/bitstreams/${event.toIndex}/href`
-        });
-        this.bundleService.patch(bundle, [moveOperation]).pipe(take(1)).subscribe((response: RestResponse) => {
+        } as Operation;
+        this.bundleService.patch(bundle, [moveOperation]).pipe(take(1)).subscribe((response: RemoteData<Bundle>) => {
           this.zone.run(() => {
             this.displayNotifications('item.edit.bitstreams.notifications.move', [response]);
             // Remove all cached requests from this bundle and call the event's callback when the requests are cleared
@@ -216,12 +217,12 @@ export class ItemBitstreamsComponent extends AbstractItemUpdateComponent impleme
    * @param key       The i18n key for the notification messages
    * @param responses The returned responses to display notifications for
    */
-  displayNotifications(key: string, responses: RestResponse[]) {
+  displayNotifications(key: string, responses: Array<RemoteData<any>>) {
     if (isNotEmpty(responses)) {
-      const failedResponses = responses.filter((response: RestResponse) => hasValue(response) && !response.isSuccessful);
-      const successfulResponses = responses.filter((response: RestResponse) => hasValue(response) && response.isSuccessful);
+      const failedResponses = responses.filter((response: RemoteData<Bundle>) => hasValue(response) && response.hasFailed);
+      const successfulResponses = responses.filter((response: RemoteData<Bundle>) => hasValue(response) && response.hasSucceeded);
 
-      failedResponses.forEach((response: ErrorResponse) => {
+      failedResponses.forEach((response: RemoteData<Bundle>) => {
         this.notificationsService.error(this.translateService.instant(`${key}.failed.title`), response.errorMessage);
       });
       if (successfulResponses.length > 0) {

src/app/+item-page/edit-item-page/item-bitstreams/item-edit-bitstream-bundle/paginated-drag-and-drop-bitstream-list/paginated-drag-and-drop-bitstream-list.component.spec.ts

@@ -7,7 +7,6 @@ import { VarDirective } from '../../../../../shared/utils/var.directive';
 import { ObjectValuesPipe } from '../../../../../shared/utils/object-values-pipe';
 import { ObjectUpdatesService } from '../../../../../core/data/object-updates/object-updates.service';
 import { BundleDataService } from '../../../../../core/data/bundle-data.service';
-import { createMockRDObs } from '../../item-bitstreams.component.spec';
 import { Bitstream } from '../../../../../core/shared/bitstream.model';
 import { BitstreamFormat } from '../../../../../core/shared/bitstream-format.model';
 import { of as observableOf } from 'rxjs/internal/observable/of';
@@ -49,7 +48,7 @@ describe('PaginatedDragAndDropBitstreamListComponent', () => {
     name: 'Fake Bitstream 1',
     bundleName: 'ORIGINAL',
     description: 'Description',
-    format: createMockRDObs(format)
+    format: createSuccessfulRemoteDataObject$(format)
   });
   const fieldUpdate1 = {
     field: bitstream1,
@@ -60,7 +59,7 @@ describe('PaginatedDragAndDropBitstreamListComponent', () => {
     name: 'Fake Bitstream 2',
     bundleName: 'ORIGINAL',
     description: 'Description',
-    format: createMockRDObs(format)
+    format: createSuccessfulRemoteDataObject$(format)
   });
   const fieldUpdate2 = {
     field: bitstream2,
@@ -107,7 +106,7 @@ describe('PaginatedDragAndDropBitstreamListComponent', () => {
     objectValuesPipe = new ObjectValuesPipe();
 
     requestService = jasmine.createSpyObj('requestService', {
-      hasByHrefObservable: observableOf(true)
+      hasByHref$: observableOf(true)
     });
 
     TestBed.configureTestingModule({

src/app/+item-page/edit-item-page/item-bitstreams/item-edit-bitstream-bundle/paginated-drag-and-drop-bitstream-list/paginated-drag-and-drop-bitstream-list.component.ts

@@ -53,7 +53,7 @@ export class PaginatedDragAndDropBitstreamListComponent extends AbstractPaginate
       switchMap((page: number) => {
         const paginatedOptions = new PaginatedSearchOptions({pagination: Object.assign({}, this.options, { currentPage: page })});
         return this.bundleService.getBitstreamsEndpoint(this.bundle.id, paginatedOptions).pipe(
-          switchMap((href) => this.requestService.hasByHrefObservable(href)),
+          switchMap((href) => this.requestService.hasByHref$(href)),
           switchMap(() => this.bundleService.getBitstreams(
             this.bundle.id,
             paginatedOptions,

src/app/+item-page/edit-item-page/item-bitstreams/item-edit-bitstream/item-edit-bitstream.component.spec.ts

@@ -6,10 +6,10 @@ import { Bitstream } from '../../../../core/shared/bitstream.model';
 import { TranslateModule } from '@ngx-translate/core';
 import { VarDirective } from '../../../../shared/utils/var.directive';
 import { NO_ERRORS_SCHEMA } from '@angular/core';
-import { createMockRDObs } from '../item-bitstreams.component.spec';
 import { BitstreamFormat } from '../../../../core/shared/bitstream-format.model';
 import { ResponsiveTableSizes } from '../../../../shared/responsive-table-sizes/responsive-table-sizes';
 import { ResponsiveColumnSizes } from '../../../../shared/responsive-table-sizes/responsive-column-sizes';
+import { createSuccessfulRemoteDataObject$ } from '../../../../shared/remote-data.utils';
 
 let comp: ItemEditBitstreamComponent;
 let fixture: ComponentFixture<ItemEditBitstreamComponent>;
@@ -29,7 +29,7 @@ const bitstream = Object.assign(new Bitstream(), {
   name: 'Fake Bitstream',
   bundleName: 'ORIGINAL',
   description: 'Description',
-  format: createMockRDObs(format)
+  format: createSuccessfulRemoteDataObject$(format)
 });
 const fieldUpdate = {
   field: bitstream,

src/app/+item-page/edit-item-page/item-bitstreams/item-edit-bitstream/item-edit-bitstream.component.ts

@@ -6,7 +6,7 @@ import { ObjectUpdatesService } from '../../../../core/data/object-updates/objec
 import { FieldChangeType } from '../../../../core/data/object-updates/object-updates.actions';
 import { Observable } from 'rxjs/internal/Observable';
 import { BitstreamFormat } from '../../../../core/shared/bitstream-format.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../../core/shared/operators';
 import { ResponsiveTableSizes } from '../../../../shared/responsive-table-sizes/responsive-table-sizes';
 import { DSONameService } from '../../../../core/breadcrumbs/dso-name.service';
 
@@ -74,7 +74,7 @@ export class ItemEditBitstreamComponent implements OnChanges, OnInit {
     this.bitstream = cloneDeep(this.fieldUpdate.field) as Bitstream;
     this.bitstreamName = this.dsoNameService.getName(this.bitstream);
     this.format$ = this.bitstream.format.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload()
     );
   }

src/app/+item-page/edit-item-page/item-collection-mapper/item-collection-mapper.component.spec.ts

@@ -12,11 +12,9 @@ import { SortDirection, SortOptions } from '../../../core/cache/models/sort-opti
 import { RestResponse } from '../../../core/cache/response.models';
 import { CollectionDataService } from '../../../core/data/collection-data.service';
 import { ItemDataService } from '../../../core/data/item-data.service';
-import { PaginatedList } from '../../../core/data/paginated-list';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Collection } from '../../../core/shared/collection.model';
 import { Item } from '../../../core/shared/item.model';
-import { PageInfo } from '../../../core/shared/page-info.model';
 import { SearchConfigurationService } from '../../../core/shared/search/search-configuration.service';
 import { SearchService } from '../../../core/shared/search/search.service';
 import { ErrorComponent } from '../../../shared/error/error.component';
@@ -38,6 +36,12 @@ import { SearchServiceStub } from '../../../shared/testing/search-service.stub';
 import { EnumKeysPipe } from '../../../shared/utils/enum-keys-pipe';
 import { VarDirective } from '../../../shared/utils/var.directive';
 import { ItemCollectionMapperComponent } from './item-collection-mapper.component';
+import {
+  createFailedRemoteDataObject$,
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 describe('ItemCollectionMapperComponent', () => {
   let comp: ItemCollectionMapperComponent;
@@ -55,7 +59,7 @@ describe('ItemCollectionMapperComponent', () => {
     id: '932c7d50-d85a-44cb-b9dc-b427b12877bd',
     name: 'test-item'
   });
-  const mockItemRD: RemoteData<Item> = new RemoteData<Item>(false, false, true, null, mockItem);
+  const mockItemRD: RemoteData<Item> = createSuccessfulRemoteDataObject(mockItem);
   const mockSearchOptions = of(new PaginatedSearchOptions({
     pagination: Object.assign(new PaginationComponentOptions(), {
       id: 'search-page-configuration',
@@ -74,10 +78,10 @@ describe('ItemCollectionMapperComponent', () => {
   const searchConfigServiceStub = {
     paginatedSearchOptions: mockSearchOptions
   };
-  const mockCollectionsRD = new RemoteData(false, false, true, null, new PaginatedList(new PageInfo(), []));
+  const mockCollectionsRD = createSuccessfulRemoteDataObject(createPaginatedList([]));
   const itemDataServiceStub = {
-    mapToCollection: () => of(new RestResponse(true, 200, 'OK')),
-    removeMappingFromCollection: () => of(new RestResponse(true, 200, 'OK')),
+    mapToCollection: () => createSuccessfulRemoteDataObject$({}),
+    removeMappingFromCollection: () => createSuccessfulRemoteDataObject$({}),
     getMappedCollections: () => of(mockCollectionsRD),
     /* tslint:disable:no-empty */
     clearMappedCollectionsRequests: () => {}
@@ -143,7 +147,7 @@ describe('ItemCollectionMapperComponent', () => {
     });
 
     it('should display an error message if at least one mapping was unsuccessful', () => {
-      spyOn(itemDataService, 'mapToCollection').and.returnValue(of(new RestResponse(false, 404, 'Not Found')));
+      spyOn(itemDataService, 'mapToCollection').and.returnValue(createFailedRemoteDataObject$('Not Found', 404));
       comp.mapCollections(ids);
       expect(notificationsService.success).not.toHaveBeenCalled();
       expect(notificationsService.error).toHaveBeenCalled();
@@ -160,7 +164,7 @@ describe('ItemCollectionMapperComponent', () => {
     });
 
     it('should display an error message if the removal of at least one mapping was unsuccessful', () => {
-      spyOn(itemDataService, 'removeMappingFromCollection').and.returnValue(of(new RestResponse(false, 404, 'Not Found')));
+      spyOn(itemDataService, 'removeMappingFromCollection').and.returnValue(createFailedRemoteDataObject$('Not Found', 404));
       comp.removeMappings(ids);
       expect(notificationsService.success).not.toHaveBeenCalled();
       expect(notificationsService.error).toHaveBeenCalled();

src/app/+item-page/edit-item-page/item-collection-mapper/item-collection-mapper.component.ts

@@ -4,13 +4,13 @@ import { ChangeDetectionStrategy, Component, OnInit, ViewChild } from '@angular/
 import { CollectionDataService } from '../../../core/data/collection-data.service';
 import { fadeIn, fadeInOut } from '../../../shared/animations/fade';
 import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { Collection } from '../../../core/shared/collection.model';
 import { Item } from '../../../core/shared/item.model';
 import {
   getFirstSucceededRemoteDataPayload,
   getRemoteDataPayload,
-  getSucceededRemoteData,
+  getFirstSucceededRemoteData,
   toDSpaceObjectListRD
 } from '../../../core/shared/operators';
 import { ActivatedRoute, Router } from '@angular/router';
@@ -20,11 +20,11 @@ import { TranslateService } from '@ngx-translate/core';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { DSpaceObjectType } from '../../../core/shared/dspace-object-type.model';
 import { isNotEmpty } from '../../../shared/empty.util';
-import { RestResponse } from '../../../core/cache/response.models';
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
 import { PaginatedSearchOptions } from '../../../shared/search/paginated-search-options.model';
 import { SearchConfigurationService } from '../../../core/shared/search/search-configuration.service';
 import { SearchService } from '../../../core/shared/search/search.service';
+import { NoContent } from '../../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-item-collection-mapper',
@@ -92,7 +92,7 @@ export class ItemCollectionMapperComponent implements OnInit {
   }
 
   ngOnInit(): void {
-    this.itemRD$ = this.route.data.pipe(map((data) => data.dso)).pipe(getSucceededRemoteData()) as Observable<RemoteData<Item>>;
+    this.itemRD$ = this.route.data.pipe(map((data) => data.dso)).pipe(getFirstSucceededRemoteData()) as Observable<RemoteData<Item>>;
     this.searchOptions$ = this.searchConfigService.paginatedSearchOptions;
     this.loadCollectionLists();
   }
@@ -141,13 +141,13 @@ export class ItemCollectionMapperComponent implements OnInit {
   mapCollections(ids: string[]) {
     const itemIdAndExcludingIds$ = observableCombineLatest(
       this.itemRD$.pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         take(1),
         map((rd: RemoteData<Item>) => rd.payload),
         map((item: Item) => item.id)
       ),
       this.itemCollectionsRD$.pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         take(1),
         map((rd: RemoteData<PaginatedList<Collection>>) => rd.payload.page),
         map((collections: Collection[]) => collections.map((collection: Collection) => collection.id))
@@ -168,7 +168,7 @@ export class ItemCollectionMapperComponent implements OnInit {
    */
   removeMappings(ids: string[]) {
     const responses$ = this.itemRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       map((itemRD: RemoteData<Item>) => itemRD.payload.id),
       switchMap((itemId: string) => observableCombineLatest(ids.map((id: string) => this.itemDataService.removeMappingFromCollection(itemId, id))))
     );
@@ -191,10 +191,10 @@ export class ItemCollectionMapperComponent implements OnInit {
    * @param {Observable<RestResponse[]>} responses$   The responses after adding/removing a mapping
    * @param {string} messagePrefix                    The prefix to build the notification messages with
    */
-  private showNotifications(responses$: Observable<RestResponse[]>, messagePrefix: string) {
-    responses$.subscribe((responses: RestResponse[]) => {
-      const successful = responses.filter((response: RestResponse) => response.isSuccessful);
-      const unsuccessful = responses.filter((response: RestResponse) => !response.isSuccessful);
+  private showNotifications(responses$: Observable<Array<RemoteData<NoContent>>>, messagePrefix: string) {
+    responses$.subscribe((responses: Array<RemoteData<NoContent>>) => {
+      const successful = responses.filter((response: RemoteData<NoContent>) => response.hasSucceeded);
+      const unsuccessful = responses.filter((response: RemoteData<NoContent>) => response.hasFailed);
       if (successful.length > 0) {
         const successMessages = observableCombineLatest(
           this.translateService.get(`${messagePrefix}.success.head`),
@@ -280,7 +280,7 @@ export class ItemCollectionMapperComponent implements OnInit {
    */
   onCancel() {
     this.itemRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       take(1)
     ).subscribe((item: Item) => {

src/app/+item-page/edit-item-page/item-delete/item-delete.component.spec.ts

@@ -16,16 +16,17 @@ import { NotificationsService } from '../../../shared/notifications/notification
 import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
 import { By } from '@angular/platform-browser';
 import { ItemDeleteComponent } from './item-delete.component';
-import { createSuccessfulRemoteDataObject } from '../../../shared/remote-data.utils';
+import {
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
 import { VarDirective } from '../../../shared/utils/var.directive';
 import { ObjectUpdatesService } from '../../../core/data/object-updates/object-updates.service';
 import { RelationshipService } from '../../../core/data/relationship.service';
 import { RelationshipType } from '../../../core/shared/item-relationships/relationship-type.model';
-import { RemoteData } from '../../../core/data/remote-data';
-import { PaginatedList } from '../../../core/data/paginated-list';
-import { PageInfo } from '../../../core/shared/page-info.model';
 import { EntityTypeService } from '../../../core/data/entity-type.service';
 import { getItemEditRoute } from '../../item-page-routing-paths';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 let comp: ItemDeleteComponent;
 let fixture: ComponentFixture<ItemDeleteComponent>;
@@ -78,52 +79,16 @@ describe('ItemDeleteComponent', () => {
       Object.assign(new Relationship(), {
         id: '1',
         uuid: 'relationship-1',
-        relationshipType: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          type1
-        )),
-        leftItem:  observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          mockItem,
-        )),
-        rightItem:  observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          Object.assign(new Item(), {})
-        )),
+        relationshipType: createSuccessfulRemoteDataObject$(type1),
+        leftItem:  createSuccessfulRemoteDataObject$(mockItem),
+        rightItem:  createSuccessfulRemoteDataObject$(new Item()),
       }),
       Object.assign(new Relationship(), {
         id: '2',
         uuid: 'relationship-2',
-        relationshipType: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          type2
-        )),
-        leftItem:  observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          mockItem,
-        )),
-        rightItem:  observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          Object.assign(new Item(), {})
-        )),
+        relationshipType: createSuccessfulRemoteDataObject$(type2),
+        leftItem:  createSuccessfulRemoteDataObject$(mockItem),
+        rightItem:  createSuccessfulRemoteDataObject$(new Item()),
       }),
     ];
 
@@ -133,7 +98,7 @@ describe('ItemDeleteComponent', () => {
     });
 
     mockItemDataService = jasmine.createSpyObj('mockItemDataService', {
-      delete: observableOf(true)
+      delete: createSuccessfulRemoteDataObject$({})
     });
 
     routeStub = {
@@ -149,20 +114,8 @@ describe('ItemDeleteComponent', () => {
 
     entityTypeService = jasmine.createSpyObj('entityTypeService',
       {
-        getEntityTypeByLabel: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          itemType,
-        )),
-        getEntityTypeRelationships: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          new PaginatedList(new PageInfo(), types),
-        )),
+        getEntityTypeByLabel: createSuccessfulRemoteDataObject$(itemType),
+        getEntityTypeRelationships: createSuccessfulRemoteDataObject$(createPaginatedList(types)),
       }
     );
 
@@ -236,5 +189,4 @@ describe('ItemDeleteComponent', () => {
       expect(routerStub.navigate).toHaveBeenCalledWith([getItemEditRoute('fake-id')]);
     });
   });
-})
-;
+});

src/app/+item-page/edit-item-page/item-delete/item-delete.component.ts

@@ -1,12 +1,21 @@
 import { Component, Input, OnInit } from '@angular/core';
-import { defaultIfEmpty, filter, first, map, switchMap, take } from 'rxjs/operators';
+import { defaultIfEmpty, filter, map, switchMap, take } from 'rxjs/operators';
 import { AbstractSimpleItemActionComponent } from '../simple-item-action/abstract-simple-item-action.component';
 import { NgbModal, NgbModalRef } from '@ng-bootstrap/ng-bootstrap';
-import { combineLatest as observableCombineLatest, combineLatest, Observable, of as observableOf } from 'rxjs';
+import {
+  combineLatest as observableCombineLatest,
+  combineLatest,
+  Observable,
+  of as observableOf
+} from 'rxjs';
 import { RelationshipType } from '../../../core/shared/item-relationships/relationship-type.model';
 import { VirtualMetadata } from '../virtual-metadata/virtual-metadata.component';
 import { Relationship } from '../../../core/shared/item-relationships/relationship.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../core/shared/operators';
+import {
+  getRemoteDataPayload,
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
+} from '../../../core/shared/operators';
 import { hasValue, isNotEmpty } from '../../../shared/empty.util';
 import { Item } from '../../../core/shared/item.model';
 import { MetadataValue } from '../../../core/shared/metadata.models';
@@ -20,8 +29,9 @@ import { RelationshipService } from '../../../core/data/relationship.service';
 import { EntityTypeService } from '../../../core/data/entity-type.service';
 import { LinkService } from '../../../core/cache/builders/link.service';
 import { followLink } from '../../../shared/utils/follow-link-config.model';
-import { RestResponse } from '../../../core/cache/response.models';
 import { getItemEditRoute } from '../../item-page-routing-paths';
+import { RemoteData } from '../../../core/data/remote-data';
+import { NoContent } from '../../../core/shared/NoContent.model';
 
 @Component({
   selector: 'ds-item-delete',
@@ -105,10 +115,10 @@ export class ItemDeleteComponent
     const label = this.item.firstMetadataValue('relationship.type');
     if (label !== undefined) {
       this.types$ = this.entityTypeService.getEntityTypeByLabel(label).pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
         switchMap((entityType) => this.entityTypeService.getEntityTypeRelationships(entityType.id)),
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
         map((relationshipTypes) => relationshipTypes.page),
         switchMap((types) =>
@@ -220,7 +230,7 @@ export class ItemDeleteComponent
       followLink('rightItem'),
     );
     return relationship.relationshipType.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       filter((relationshipType: RelationshipType) => hasValue(relationshipType) && isNotEmpty(relationshipType.uuid))
     );
@@ -238,7 +248,7 @@ export class ItemDeleteComponent
         relationship,
         this.isLeftItem(relationship).pipe(
           switchMap((isLeftItem) => isLeftItem ? relationship.rightItem : relationship.leftItem),
-          getSucceededRemoteData(),
+          getFirstSucceededRemoteData(),
           getRemoteDataPayload(),
         ),
       );
@@ -285,7 +295,7 @@ export class ItemDeleteComponent
   private isLeftItem(relationship: Relationship): Observable<boolean> {
 
     return relationship.leftItem.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
       filter((item: Item) => hasValue(item) && isNotEmpty(item.uuid)),
       map((leftItem) => leftItem.uuid === this.item.uuid)
@@ -327,9 +337,9 @@ export class ItemDeleteComponent
         )
       ),
     ).subscribe((types) => {
-      this.itemDataService.delete(this.item.id, types).pipe(first()).subscribe(
-        (response: RestResponse) => {
-          this.notify(response.isSuccessful);
+      this.itemDataService.delete(this.item.id, types).pipe(getFirstCompletedRemoteData()).subscribe(
+        (rd: RemoteData<NoContent>) => {
+          this.notify(rd.hasSucceeded);
         }
       );
     });

src/app/+item-page/edit-item-page/item-metadata/edit-in-place-field/edit-in-place-field.component.spec.ts

@@ -9,7 +9,7 @@ import { TestScheduler } from 'rxjs/testing';
 import { MetadataFieldDataService } from '../../../../core/data/metadata-field-data.service';
 import { FieldChangeType } from '../../../../core/data/object-updates/object-updates.actions';
 import { ObjectUpdatesService } from '../../../../core/data/object-updates/object-updates.service';
-import { PaginatedList } from '../../../../core/data/paginated-list';
+import { PaginatedList, buildPaginatedList } from '../../../../core/data/paginated-list.model';
 import { MetadataField } from '../../../../core/metadata/metadata-field.model';
 import { MetadataSchema } from '../../../../core/metadata/metadata-schema.model';
 import { RegistryService } from '../../../../core/registry/registry.service';
@@ -66,7 +66,7 @@ describe('EditInPlaceFieldComponent', () => {
   beforeEach(async(() => {
     scheduler = getTestScheduler();
 
-    paginatedMetadataFields = new PaginatedList(undefined, [mdField1, mdField2, mdField3]);
+    paginatedMetadataFields = buildPaginatedList(undefined, [mdField1, mdField2, mdField3]);
 
     metadataFieldService = jasmine.createSpyObj({
       queryMetadataFields: createSuccessfulRemoteDataObject$(paginatedMetadataFields),
@@ -221,7 +221,7 @@ describe('EditInPlaceFieldComponent', () => {
     }));
 
     it('it should call queryMetadataFields on the metadataFieldService with the correct query', () => {
-      expect(metadataFieldService.queryMetadataFields).toHaveBeenCalledWith(query, null, followLink('schema'));
+      expect(metadataFieldService.queryMetadataFields).toHaveBeenCalledWith(query, null, false, followLink('schema'));
     });
 
     it('it should set metadataFieldSuggestions to the right value', () => {

src/app/+item-page/edit-item-page/item-metadata/edit-in-place-field/edit-in-place-field.component.ts

@@ -1,10 +1,13 @@
 import { Component, Input, OnChanges, OnInit } from '@angular/core';
-import { metadataFieldsToString } from '../../../../core/shared/operators';
+import {
+  metadataFieldsToString,
+  getFirstSucceededRemoteData
+} from '../../../../core/shared/operators';
 import { hasValue, isNotEmpty } from '../../../../shared/empty.util';
 import { RegistryService } from '../../../../core/registry/registry.service';
 import { cloneDeep } from 'lodash';
 import { BehaviorSubject, Observable, of as observableOf } from 'rxjs';
-import { map, take } from 'rxjs/operators';
+import { map } from 'rxjs/operators';
 import { FieldChangeType } from '../../../../core/data/object-updates/object-updates.actions';
 import { FieldUpdate } from '../../../../core/data/object-updates/object-updates.reducer';
 import { ObjectUpdatesService } from '../../../../core/data/object-updates/object-updates.service';
@@ -124,10 +127,10 @@ export class EditInPlaceFieldComponent implements OnInit, OnChanges {
    */
   findMetadataFieldSuggestions(query: string) {
     if (isNotEmpty(query)) {
-      return this.registryService.queryMetadataFields(query, null, followLink('schema')).pipe(
+      return this.registryService.queryMetadataFields(query, null, false, followLink('schema')).pipe(
+        getFirstSucceededRemoteData(),
         metadataFieldsToString(),
-        take(1))
-        .subscribe((fieldNames: string[]) => {
+      ).subscribe((fieldNames: string[]) => {
           this.setInputSuggestions(fieldNames);
         })
     } else {

src/app/+item-page/edit-item-page/item-metadata/item-metadata.component.spec.ts

@@ -21,7 +21,6 @@ import { Item } from '../../../core/shared/item.model';
 import { FieldChangeType } from '../../../core/data/object-updates/object-updates.actions';
 import { MetadatumViewModel } from '../../../core/shared/metadata.models';
 import { RegistryService } from '../../../core/registry/registry.service';
-import { PaginatedList } from '../../../core/data/paginated-list';
 import { MetadataSchema } from '../../../core/metadata/metadata-schema.model';
 import { MetadataField } from '../../../core/metadata/metadata-field.model';
 import {
@@ -30,6 +29,7 @@ import {
 } from '../../../shared/remote-data.utils';
 import { ObjectCacheService } from '../../../core/cache/object-cache.service';
 import { DSOSuccessResponse } from '../../../core/cache/response.models';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 let comp: any;
 let fixture: ComponentFixture<ItemMetadataComponent>;
@@ -133,7 +133,7 @@ describe('ItemMetadataComponent', () => {
           data: observableOf({ dso: createSuccessfulRemoteDataObject(item) })
         }
       };
-      paginatedMetadataFields = new PaginatedList(undefined, [mdField1, mdField2, mdField3]);
+      paginatedMetadataFields = createPaginatedList([mdField1, mdField2, mdField3]);
 
       metadataFieldService = jasmine.createSpyObj({
         getAllMetadataFields: createSuccessfulRemoteDataObject$(paginatedMetadataFields)

src/app/+item-page/edit-item-page/item-metadata/item-metadata.component.ts

@@ -4,19 +4,18 @@ import { ItemDataService } from '../../../core/data/item-data.service';
 import { ObjectUpdatesService } from '../../../core/data/object-updates/object-updates.service';
 import { ActivatedRoute, Router } from '@angular/router';
 import { cloneDeep } from 'lodash';
-import { first, switchMap, tap } from 'rxjs/operators';
-import { getSucceededRemoteData } from '../../../core/shared/operators';
+import { first, switchMap } from 'rxjs/operators';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 import { RemoteData } from '../../../core/data/remote-data';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
 import { MetadataValue, MetadatumViewModel } from '../../../core/shared/metadata.models';
 import { AbstractItemUpdateComponent } from '../abstract-item-update/abstract-item-update.component';
 import { UpdateDataService } from '../../../core/data/update-data.service';
-import { hasNoValue, hasValue, isNotEmpty } from '../../../shared/empty.util';
+import { hasNoValue, hasValue } from '../../../shared/empty.util';
 import { AlertType } from '../../../shared/alert/aletr-type';
 import { Operation } from 'fast-json-patch';
-import { METADATA_PATCH_OPERATION_SERVICE_TOKEN } from '../../../core/data/object-updates/patch-operation-service/metadata-patch-operation.service';
-import { DSOSuccessResponse, ErrorResponse } from '../../../core/cache/response.models';
+import { MetadataPatchOperationService } from '../../../core/data/object-updates/patch-operation-service/metadata-patch-operation.service';
 
 @Component({
   selector: 'ds-item-metadata',
@@ -87,7 +86,7 @@ export class ItemMetadataComponent extends AbstractItemUpdateComponent {
    * Sends all initial values of this item to the object updates service
    */
   public initializeOriginalFields() {
-    this.objectUpdatesService.initialize(this.url, this.item.metadataAsList, this.item.lastModified, METADATA_PATCH_OPERATION_SERVICE_TOKEN);
+    this.objectUpdatesService.initialize(this.url, this.item.metadataAsList, this.item.lastModified, MetadataPatchOperationService);
   }
 
   /**
@@ -101,27 +100,21 @@ export class ItemMetadataComponent extends AbstractItemUpdateComponent {
           first(),
           switchMap((patch: Operation[]) => {
             return this.updateService.patch(this.item, patch).pipe(
-              tap((response) => {
-                if (!response.isSuccessful) {
-                  this.notificationsService.error(this.getNotificationTitle('error'), (response as ErrorResponse).errorMessage);
-                }
-              }),
-              switchMap((response: DSOSuccessResponse) => {
-                if (isNotEmpty(response.resourceSelfLinks)) {
-                  return this.itemService.findByHref(response.resourceSelfLinks[0]);
-                }
-              }),
-              getSucceededRemoteData()
+              getFirstCompletedRemoteData()
             );
           })
         ).subscribe(
           (rd: RemoteData<Item>) => {
+            if (rd.hasFailed) {
+              this.notificationsService.error(this.getNotificationTitle('error'), rd.errorMessage);
+            } else {
               this.item = rd.payload;
               this.checkAndFixMetadataUUIDs();
               this.initializeOriginalFields();
               this.updates$ = this.objectUpdatesService.getFieldUpdates(this.url, this.item.metadataAsList);
               this.notificationsService.success(this.getNotificationTitle('saved'), this.getNotificationContent('saved'));
             }
+          }
         )
       } else {
         this.notificationsService.error(this.getNotificationTitle('invalid'), this.getNotificationContent('invalid'));

src/app/+item-page/edit-item-page/item-move/item-move.component.spec.ts

@@ -7,10 +7,7 @@ import { RouterTestingModule } from '@angular/router/testing';
 import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateModule } from '@ngx-translate/core';
 import { of as observableOf } from 'rxjs';
-import { RestResponse } from '../../../core/cache/response.models';
 import { ItemDataService } from '../../../core/data/item-data.service';
-import { PaginatedList } from '../../../core/data/paginated-list';
-import { RemoteData } from '../../../core/data/remote-data';
 import { Collection } from '../../../core/shared/collection.model';
 import { Item } from '../../../core/shared/item.model';
 import { SearchService } from '../../../core/shared/search/search.service';
@@ -18,6 +15,12 @@ import { NotificationsService } from '../../../shared/notifications/notification
 import { NotificationsServiceStub } from '../../../shared/testing/notifications-service.stub';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { ItemMoveComponent } from './item-move.component';
+import {
+  createFailedRemoteDataObject$,
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 describe('ItemMoveComponent', () => {
   let comp: ItemMoveComponent;
@@ -34,22 +37,6 @@ describe('ItemMoveComponent', () => {
     url: `${itemPageUrl}/edit`
   });
 
-  const mockItemDataService = jasmine.createSpyObj({
-    moveToCollection: observableOf(new RestResponse(true, 200, 'Success'))
-  });
-
-  const mockItemDataServiceFail = jasmine.createSpyObj({
-    moveToCollection: observableOf(new RestResponse(false, 500, 'Internal server error'))
-  });
-
-  const routeStub = {
-    data: observableOf({
-      dso: new RemoteData(false, false, true, null, {
-        id: 'item1'
-      })
-    })
-  };
-
   const collection1 = Object.assign(new Collection(), {
     uuid: 'collection-uuid-1',
     name: 'Test collection 1'
@@ -60,10 +47,25 @@ describe('ItemMoveComponent', () => {
     name: 'Test collection 2'
   });
 
+  const mockItemDataService = jasmine.createSpyObj({
+    moveToCollection: createSuccessfulRemoteDataObject$(collection1)
+  });
+
+  const mockItemDataServiceFail = jasmine.createSpyObj({
+    moveToCollection: createFailedRemoteDataObject$('Internal server error', 500)
+  });
+
+  const routeStub = {
+    data: observableOf({
+      dso: createSuccessfulRemoteDataObject({
+        id: 'item1'
+      })
+    })
+  };
+
   const mockSearchService = {
     search: () => {
-      return observableOf(new RemoteData(false, false, true, null,
-        new PaginatedList(null, [
+      return createSuccessfulRemoteDataObject$(createPaginatedList([
         {
           indexableObject: collection1,
           hitHighlights: {}
@@ -71,7 +73,7 @@ describe('ItemMoveComponent', () => {
           indexableObject: collection2,
           hitHighlights: {}
         }
-        ])));
+      ]));
     }
   };
 

src/app/+item-page/edit-item-page/item-move/item-move.component.ts

@@ -3,15 +3,17 @@ import { first, map } from 'rxjs/operators';
 import { DSpaceObjectType } from '../../../core/shared/dspace-object-type.model';
 import { RemoteData } from '../../../core/data/remote-data';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
-import { PaginatedList } from '../../../core/data/paginated-list';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
 import { Item } from '../../../core/shared/item.model';
 import { ActivatedRoute, Router } from '@angular/router';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
-import { getSucceededRemoteData } from '../../../core/shared/operators';
+import {
+  getFirstSucceededRemoteData,
+  getFirstCompletedRemoteData
+} from '../../../core/shared/operators';
 import { ItemDataService } from '../../../core/data/item-data.service';
 import { Observable, of as observableOf } from 'rxjs';
-import { RestResponse } from '../../../core/cache/response.models';
 import { Collection } from '../../../core/shared/collection.model';
 import { PaginationComponentOptions } from '../../../shared/pagination/pagination-component-options.model';
 import { SearchService } from '../../../core/shared/search/search.service';
@@ -55,7 +57,7 @@ export class ItemMoveComponent implements OnInit {
   }
 
   ngOnInit(): void {
-    this.itemRD$ = this.route.data.pipe(map((data) => data.dso), getSucceededRemoteData()) as Observable<RemoteData<Item>>;
+    this.itemRD$ = this.route.data.pipe(map((data) => data.dso), getFirstSucceededRemoteData()) as Observable<RemoteData<Item>>;
     this.itemRD$.subscribe((rd) => {
         this.itemId = rd.payload.id;
       }
@@ -114,10 +116,10 @@ export class ItemMoveComponent implements OnInit {
    */
   moveCollection() {
     this.processing = true;
-    this.itemDataService.moveToCollection(this.itemId, this.selectedCollection).pipe(first()).subscribe(
-      (response: RestResponse) => {
+    this.itemDataService.moveToCollection(this.itemId, this.selectedCollection).pipe(getFirstCompletedRemoteData()).subscribe(
+      (response: RemoteData<Collection>) => {
         this.router.navigate([getItemEditRoute(this.itemId)]);
-        if (response.isSuccessful) {
+        if (response.hasSucceeded) {
           this.notificationsService.success(this.translateService.get('item.edit.move.success'));
         } else {
           this.notificationsService.error(this.translateService.get('item.edit.move.error'));

src/app/+item-page/edit-item-page/item-private/item-private.component.spec.ts

@@ -2,7 +2,6 @@ import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { Item } from '../../../core/shared/item.model';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { of as observableOf } from 'rxjs';
-import { RemoteData } from '../../../core/data/remote-data';
 import { NotificationsServiceStub } from '../../../shared/testing/notifications-service.stub';
 import { CommonModule } from '@angular/common';
 import { FormsModule } from '@angular/forms';
@@ -16,7 +15,7 @@ import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
 import { By } from '@angular/platform-browser';
 import { ItemPrivateComponent } from './item-private.component';
 import { RestResponse } from '../../../core/cache/response.models';
-import { createSuccessfulRemoteDataObject } from '../../../shared/remote-data.utils';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
 
 let comp: ItemPrivateComponent;
 let fixture: ComponentFixture<ItemPrivateComponent>;
@@ -46,14 +45,12 @@ describe('ItemPrivateComponent', () => {
     });
 
     mockItemDataService = jasmine.createSpyObj('mockItemDataService', {
-      setDiscoverable: observableOf(new RestResponse(true, 200, 'OK'))
+      setDiscoverable: createSuccessfulRemoteDataObject$(mockItem)
     });
 
     routeStub = {
       data: observableOf({
-        dso: createSuccessfulRemoteDataObject({
-          id: 'fake-id'
-        })
+        dso: createSuccessfulRemoteDataObject(mockItem)
       })
     };
 
@@ -98,9 +95,8 @@ describe('ItemPrivateComponent', () => {
       spyOn(comp, 'processRestResponse');
       comp.performAction();
 
-      expect(mockItemDataService.setDiscoverable).toHaveBeenCalledWith(mockItem.id, false);
+      expect(mockItemDataService.setDiscoverable).toHaveBeenCalledWith(mockItem, false);
       expect(comp.processRestResponse).toHaveBeenCalled();
     });
   });
-})
-;
+});

src/app/+item-page/edit-item-page/item-private/item-private.component.ts

@@ -1,9 +1,8 @@
 import { Component } from '@angular/core';
-import { first } from 'rxjs/operators';
 import { AbstractSimpleItemActionComponent } from '../simple-item-action/abstract-simple-item-action.component';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Item } from '../../../core/shared/item.model';
-import { RestResponse } from '../../../core/cache/response.models';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 
 @Component({
   selector: 'ds-item-private',
@@ -21,9 +20,9 @@ export class ItemPrivateComponent extends AbstractSimpleItemActionComponent {
    * Perform the make private action to the item
    */
   performAction() {
-    this.itemDataService.setDiscoverable(this.item.id, false).pipe(first()).subscribe(
-      (response: RestResponse) => {
-        this.processRestResponse(response);
+    this.itemDataService.setDiscoverable(this.item, false).pipe(getFirstCompletedRemoteData()).subscribe(
+      (rd: RemoteData<Item>) => {
+        this.processRestResponse(rd);
       }
     );
   }

src/app/+item-page/edit-item-page/item-public/item-public.component.spec.ts

@@ -2,7 +2,6 @@ import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { Item } from '../../../core/shared/item.model';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { of as observableOf } from 'rxjs';
-import { RemoteData } from '../../../core/data/remote-data';
 import { NotificationsServiceStub } from '../../../shared/testing/notifications-service.stub';
 import { CommonModule } from '@angular/common';
 import { FormsModule } from '@angular/forms';
@@ -15,8 +14,7 @@ import { NotificationsService } from '../../../shared/notifications/notification
 import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
 import { By } from '@angular/platform-browser';
 import { ItemPublicComponent } from './item-public.component';
-import { RestResponse } from '../../../core/cache/response.models';
-import { createSuccessfulRemoteDataObject } from '../../../shared/remote-data.utils';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
 
 let comp: ItemPublicComponent;
 let fixture: ComponentFixture<ItemPublicComponent>;
@@ -27,8 +25,6 @@ let routerStub;
 let mockItemDataService: ItemDataService;
 let routeStub;
 let notificationsServiceStub;
-let successfulRestResponse;
-let failRestResponse;
 
 describe('ItemPublicComponent', () => {
   beforeEach(async(() => {
@@ -46,14 +42,12 @@ describe('ItemPublicComponent', () => {
     });
 
     mockItemDataService = jasmine.createSpyObj('mockItemDataService', {
-      setDiscoverable: observableOf(new RestResponse(true, 200, 'OK'))
+      setDiscoverable: createSuccessfulRemoteDataObject$(mockItem)
     });
 
     routeStub = {
       data: observableOf({
-        dso: createSuccessfulRemoteDataObject({
-          id: 'fake-id'
-        })
+        dso: createSuccessfulRemoteDataObject(mockItem)
       })
     };
 
@@ -74,9 +68,6 @@ describe('ItemPublicComponent', () => {
   }));
 
   beforeEach(() => {
-    successfulRestResponse = new RestResponse(true, 200, 'OK');
-    failRestResponse = new RestResponse(false, 500, 'Internal Server Error');
-
     fixture = TestBed.createComponent(ItemPublicComponent);
     comp = fixture.componentInstance;
     fixture.detectChanges();
@@ -98,9 +89,8 @@ describe('ItemPublicComponent', () => {
       spyOn(comp, 'processRestResponse');
       comp.performAction();
 
-      expect(mockItemDataService.setDiscoverable).toHaveBeenCalledWith(mockItem.id, true);
+      expect(mockItemDataService.setDiscoverable).toHaveBeenCalledWith(mockItem, true);
       expect(comp.processRestResponse).toHaveBeenCalled();
     });
   });
-})
-;
+});

src/app/+item-page/edit-item-page/item-public/item-public.component.ts

@@ -1,9 +1,8 @@
 import { Component } from '@angular/core';
-import { first } from 'rxjs/operators';
 import { AbstractSimpleItemActionComponent } from '../simple-item-action/abstract-simple-item-action.component';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Item } from '../../../core/shared/item.model';
-import { RestResponse } from '../../../core/cache/response.models';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 
 @Component({
   selector: 'ds-item-public',
@@ -21,8 +20,8 @@ export class ItemPublicComponent extends AbstractSimpleItemActionComponent {
    * Perform the make public action to the item
    */
   performAction() {
-    this.itemDataService.setDiscoverable(this.item.id, true).pipe(first()).subscribe(
-      (response: RestResponse) => {
+    this.itemDataService.setDiscoverable(this.item, true).pipe(getFirstCompletedRemoteData()).subscribe(
+      (response: RemoteData<Item>) => {
         this.processRestResponse(response);
       }
     );

src/app/+item-page/edit-item-page/item-reinstate/item-reinstate.component.spec.ts

@@ -2,7 +2,6 @@ import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { Item } from '../../../core/shared/item.model';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { of as observableOf } from 'rxjs';
-import { RemoteData } from '../../../core/data/remote-data';
 import { NotificationsServiceStub } from '../../../shared/testing/notifications-service.stub';
 import { CommonModule } from '@angular/common';
 import { FormsModule } from '@angular/forms';
@@ -15,8 +14,10 @@ import { NotificationsService } from '../../../shared/notifications/notification
 import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
 import { By } from '@angular/platform-browser';
 import { ItemReinstateComponent } from './item-reinstate.component';
-import { RestResponse } from '../../../core/cache/response.models';
-import { createSuccessfulRemoteDataObject } from '../../../shared/remote-data.utils';
+import {
+  createSuccessfulRemoteDataObject,
+  createSuccessfulRemoteDataObject$
+} from '../../../shared/remote-data.utils';
 
 let comp: ItemReinstateComponent;
 let fixture: ComponentFixture<ItemReinstateComponent>;
@@ -27,8 +28,6 @@ let routerStub;
 let mockItemDataService: ItemDataService;
 let routeStub;
 let notificationsServiceStub;
-let successfulRestResponse;
-let failRestResponse;
 
 describe('ItemReinstateComponent', () => {
   beforeEach(async(() => {
@@ -46,7 +45,7 @@ describe('ItemReinstateComponent', () => {
     });
 
     mockItemDataService = jasmine.createSpyObj('mockItemDataService', {
-      setWithDrawn: observableOf(new RestResponse(true, 200, 'OK'))
+      setWithDrawn: createSuccessfulRemoteDataObject$(mockItem)
     });
 
     routeStub = {
@@ -74,9 +73,6 @@ describe('ItemReinstateComponent', () => {
   }));
 
   beforeEach(() => {
-    successfulRestResponse = new RestResponse(true, 200, 'OK');
-    failRestResponse = new RestResponse(false, 500, 'Internal Server Error');
-
     fixture = TestBed.createComponent(ItemReinstateComponent);
     comp = fixture.componentInstance;
     fixture.detectChanges();
@@ -98,9 +94,8 @@ describe('ItemReinstateComponent', () => {
       spyOn(comp, 'processRestResponse');
       comp.performAction();
 
-      expect(mockItemDataService.setWithDrawn).toHaveBeenCalledWith(mockItem.id, false);
+      expect(mockItemDataService.setWithDrawn).toHaveBeenCalledWith(comp.item, false);
       expect(comp.processRestResponse).toHaveBeenCalled();
     });
   });
-})
-;
+});

src/app/+item-page/edit-item-page/item-reinstate/item-reinstate.component.ts

@@ -1,9 +1,8 @@
 import { Component } from '@angular/core';
-import { first } from 'rxjs/operators';
 import { AbstractSimpleItemActionComponent } from '../simple-item-action/abstract-simple-item-action.component';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Item } from '../../../core/shared/item.model';
-import { RestResponse } from '../../../core/cache/response.models';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 
 @Component({
   selector: 'ds-item-reinstate',
@@ -21,8 +20,8 @@ export class ItemReinstateComponent extends AbstractSimpleItemActionComponent {
    * Perform the reinstate action to the item
    */
   performAction() {
-    this.itemDataService.setWithDrawn(this.item.id, false).pipe(first()).subscribe(
-      (response: RestResponse) => {
+    this.itemDataService.setWithDrawn(this.item, false).pipe(getFirstCompletedRemoteData()).subscribe(
+      (response: RemoteData<Item>) => {
         this.processRestResponse(response);
       }
     );

src/app/+item-page/edit-item-page/item-relationships/edit-relationship-list/edit-relationship-list.component.spec.ts

@@ -6,19 +6,16 @@ import { of as observableOf } from 'rxjs/internal/observable/of';
 import { LinkService } from '../../../../core/cache/builders/link.service';
 import { FieldChangeType } from '../../../../core/data/object-updates/object-updates.actions';
 import { ObjectUpdatesService } from '../../../../core/data/object-updates/object-updates.service';
-import { PaginatedList } from '../../../../core/data/paginated-list';
-import { RelationshipTypeService } from '../../../../core/data/relationship-type.service';
 import { RelationshipService } from '../../../../core/data/relationship.service';
-import { RemoteData } from '../../../../core/data/remote-data';
 import { ItemType } from '../../../../core/shared/item-relationships/item-type.model';
 import { RelationshipType } from '../../../../core/shared/item-relationships/relationship-type.model';
 import { Relationship } from '../../../../core/shared/item-relationships/relationship.model';
 import { Item } from '../../../../core/shared/item.model';
-import { PageInfo } from '../../../../core/shared/page-info.model';
-import { getMockLinkService } from '../../../../shared/mocks/link-service.mock';
 import { SelectableListService } from '../../../../shared/object-list/selectable-list/selectable-list.service';
 import { SharedModule } from '../../../../shared/shared.module';
 import { EditRelationshipListComponent } from './edit-relationship-list.component';
+import { createSuccessfulRemoteDataObject$ } from '../../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../../shared/testing/utils.test';
 
 let comp: EditRelationshipListComponent;
 let fixture: ComponentFixture<EditRelationshipListComponent>;
@@ -60,20 +57,8 @@ describe('EditRelationshipListComponent', () => {
     relationshipType = Object.assign(new RelationshipType(), {
       id: '1',
       uuid: '1',
-      leftType: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          entityType,
-        )),
-      rightType: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          relatedEntityType,
-        )),
+      leftType: createSuccessfulRemoteDataObject$(entityType),
+      rightType: createSuccessfulRemoteDataObject$(relatedEntityType),
       leftwardType: 'isAuthorOfPublication',
       rightwardType: 'isPublicationOfAuthor',
     });
@@ -92,53 +77,17 @@ describe('EditRelationshipListComponent', () => {
         self: url + '/2',
         id: '2',
         uuid: '2',
-        relationshipType: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          relationshipType
-        )),
-        leftItem: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          item,
-        )),
-        rightItem: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          author1,
-        )),
+        relationshipType: createSuccessfulRemoteDataObject$(relationshipType),
+        leftItem: createSuccessfulRemoteDataObject$(item),
+        rightItem: createSuccessfulRemoteDataObject$(author1),
       }),
       Object.assign(new Relationship(), {
         self: url + '/3',
         id: '3',
         uuid: '3',
-        relationshipType: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          relationshipType
-        )),
-        leftItem: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          item,
-        )),
-        rightItem: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          undefined,
-          author2,
-        )),
+        relationshipType: createSuccessfulRemoteDataObject$(relationshipType),
+        leftItem: createSuccessfulRemoteDataObject$(item),
+        rightItem: createSuccessfulRemoteDataObject$(author2),
       })
     ];
 
@@ -148,13 +97,7 @@ describe('EditRelationshipListComponent', () => {
       },
       id: 'publication',
       uuid: 'publication',
-      relationships: observableOf(new RemoteData(
-        false,
-        false,
-        true,
-        undefined,
-        new PaginatedList(new PageInfo(), relationships),
-      ))
+      relationships: createSuccessfulRemoteDataObject$(createPaginatedList(relationships))
     });
 
     fieldUpdate1 = {
@@ -185,8 +128,8 @@ describe('EditRelationshipListComponent', () => {
 
     relationshipService = jasmine.createSpyObj('relationshipService',
       {
-        getRelatedItemsByLabel: observableOf(new RemoteData(false, false, true, null, new PaginatedList(new PageInfo(), [author1, author2]))),
-        getItemRelationshipsByLabel: observableOf(new RemoteData(false, false, true, null, new PaginatedList(new PageInfo(), relationships))),
+        getRelatedItemsByLabel: createSuccessfulRemoteDataObject$(createPaginatedList([author1, author2])),
+        getItemRelationshipsByLabel: createSuccessfulRemoteDataObject$(createPaginatedList(relationships)),
         isLeftItem: observableOf(true),
       }
     );

src/app/+item-page/edit-item-page/item-relationships/edit-relationship-list/edit-relationship-list.component.ts

@@ -11,19 +11,14 @@ import {
 } from '../../../../core/data/object-updates/object-updates.reducer';
 import { RelationshipService } from '../../../../core/data/relationship.service';
 import { Item } from '../../../../core/shared/item.model';
-import {
-  defaultIfEmpty, filter, flatMap,
-  map,
-  switchMap,
-  take, tap,
-} from 'rxjs/operators';
-import { hasValue } from '../../../../shared/empty.util';
+import { defaultIfEmpty, flatMap, map, switchMap, take, } from 'rxjs/operators';
+import { hasValue, hasValueOperator } from '../../../../shared/empty.util';
 import { Relationship } from '../../../../core/shared/item-relationships/relationship.model';
 import { RelationshipType } from '../../../../core/shared/item-relationships/relationship-type.model';
 import {
   getAllSucceededRemoteData,
   getRemoteDataPayload,
-  getSucceededRemoteData
+  getFirstSucceededRemoteData,
 } from '../../../../core/shared/operators';
 import { combineLatest as observableCombineLatest, of } from 'rxjs';
 import { ItemType } from '../../../../core/shared/item-relationships/item-type.model';
@@ -33,6 +28,8 @@ import { ItemSearchResult } from '../../../../shared/object-collection/shared/it
 import { SelectableListService } from '../../../../shared/object-list/selectable-list/selectable-list.service';
 import { SearchResult } from '../../../../shared/search/search-result.model';
 import { followLink } from '../../../../shared/utils/follow-link-config.model';
+import { PaginatedList } from '../../../../core/data/paginated-list.model';
+import { RemoteData } from '../../../../core/data/remote-data';
 
 @Component({
   selector: 'ds-edit-relationship-list',
@@ -121,10 +118,10 @@ export class EditRelationshipListComponent implements OnInit {
       this.relationshipType.leftType,
       this.relationshipType.rightType,
     ].map((itemTypeRD) => itemTypeRD.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
     ))).pipe(
-      map((itemTypes) => [
+      map((itemTypes: ItemType[]) => [
         this.relationshipType.leftwardType,
         this.relationshipType.rightwardType,
       ][itemTypes.findIndex((itemType) => itemType.id === this.itemType.id)]),
@@ -259,9 +256,9 @@ export class EditRelationshipListComponent implements OnInit {
   private getRelatedItem(relationship: Relationship): Observable<Item> {
     return this.relationshipService.isLeftItem(relationship, this.item).pipe(
       switchMap((isLeftItem) => isLeftItem ? relationship.rightItem : relationship.leftItem),
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
-    )
+    ) as Observable<Item>
   }
 
   ngOnInit(): void {
@@ -271,10 +268,11 @@ export class EditRelationshipListComponent implements OnInit {
         this.relationshipType.leftType,
         this.relationshipType.rightType,
       ].map((type) => type.pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
       ))).pipe(
-        map((relatedTypes) => relatedTypes.find((relatedType) => relatedType.uuid !== this.itemType.uuid)),
+        map((relatedTypes: ItemType[]) => relatedTypes.find((relatedType) => relatedType.uuid !== this.itemType.uuid)),
+        hasValueOperator()
       );
 
     this.relatedEntityType$.pipe(
@@ -304,10 +302,12 @@ export class EditRelationshipListComponent implements OnInit {
         map((fieldUpdates) => {
           const fieldUpdatesFiltered: FieldUpdates = {};
           Object.keys(fieldUpdates).forEach((uuid) => {
+            if (hasValue(fieldUpdates[uuid])) {
               const field = fieldUpdates[uuid].field;
               if ((field as RelationshipIdentifiable).type.id === this.relationshipType.id) {
                 fieldUpdatesFiltered[uuid] = fieldUpdates[uuid];
               }
+            }
           });
           return fieldUpdatesFiltered;
         }),
@@ -316,26 +316,20 @@ export class EditRelationshipListComponent implements OnInit {
   }
 
   private getItemRelationships() {
-    this.linkService.resolveLink(this.item, followLink('relationships'));
-    return this.item.relationships.pipe(
-      getAllSucceededRemoteData(),
-      map((relationships) => relationships.payload.page.filter((relationship) => relationship)),
-      filter((relationships) => relationships.every((relationship) => !!relationship)),
-      tap((relationships: Relationship[]) =>
-        relationships.forEach((relationship: Relationship) => {
-          this.linkService.resolveLinks(
-            relationship,
+    this.linkService.resolveLink(this.item,
+      followLink('relationships', undefined, true,
         followLink('relationshipType'),
         followLink('leftItem'),
         followLink('rightItem'),
-          );
-        })
-      ),
+      ));
+    return this.item.relationships.pipe(
+      getAllSucceededRemoteData(),
+      map((relationships: RemoteData<PaginatedList<Relationship>>) => relationships.payload.page.filter((relationship: Relationship) => hasValue(relationship))),
       switchMap((itemRelationships: Relationship[]) =>
         observableCombineLatest(
           itemRelationships
             .map((relationship) => relationship.relationshipType.pipe(
-              getSucceededRemoteData(),
+              getFirstSucceededRemoteData(),
               getRemoteDataPayload(),
             ))
         ).pipe(

src/app/+item-page/edit-item-page/item-relationships/edit-relationship/edit-relationship.component.spec.ts

@@ -4,14 +4,13 @@ import { TranslateModule } from '@ngx-translate/core';
 import { of as observableOf } from 'rxjs/internal/observable/of';
 import { FieldChangeType } from '../../../../core/data/object-updates/object-updates.actions';
 import { ObjectUpdatesService } from '../../../../core/data/object-updates/object-updates.service';
-import { PaginatedList } from '../../../../core/data/paginated-list';
-import { RemoteData } from '../../../../core/data/remote-data';
 import { RelationshipType } from '../../../../core/shared/item-relationships/relationship-type.model';
 import { Relationship } from '../../../../core/shared/item-relationships/relationship.model';
 import { Item } from '../../../../core/shared/item.model';
-import { PageInfo } from '../../../../core/shared/page-info.model';
 import { EditRelationshipComponent } from './edit-relationship.component';
 import { NgbModal } from '@ng-bootstrap/ng-bootstrap';
+import { createSuccessfulRemoteDataObject$ } from '../../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../../shared/testing/utils.test';
 
 let objectUpdatesService;
 const url = 'http://test-url.com/test-url';
@@ -49,7 +48,7 @@ describe('EditRelationshipComponent', () => {
       },
       id: 'publication',
       uuid: 'publication',
-      relationships: observableOf(new RemoteData(false, false, true, undefined, new PaginatedList(new PageInfo(), relationships)))
+      relationships: createSuccessfulRemoteDataObject$(createPaginatedList(relationships))
     });
 
     relatedItem = Object.assign(new Item(), {
@@ -65,9 +64,9 @@ describe('EditRelationshipComponent', () => {
         uuid: '2',
         leftId: 'author1',
         rightId: 'publication',
-        relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType)),
-        leftItem: observableOf(new RemoteData(false, false, true, undefined, relatedItem)),
-        rightItem: observableOf(new RemoteData(false, false, true, undefined, item)),
+        relationshipType: createSuccessfulRemoteDataObject$(relationshipType),
+        leftItem: createSuccessfulRemoteDataObject$(relatedItem),
+        rightItem: createSuccessfulRemoteDataObject$(item),
       }),
       Object.assign(new Relationship(), {
         _links: {
@@ -77,7 +76,7 @@ describe('EditRelationshipComponent', () => {
         uuid: '3',
         leftId: 'author2',
         rightId: 'publication',
-        relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
+        relationshipType: createSuccessfulRemoteDataObject$(relationshipType)
       })
     ];
 

src/app/+item-page/edit-item-page/item-relationships/edit-relationship/edit-relationship.component.ts

@@ -9,7 +9,7 @@ import {
 } from '../../../../core/data/object-updates/object-updates.reducer';
 import { ObjectUpdatesService } from '../../../../core/data/object-updates/object-updates.service';
 import { Item } from '../../../../core/shared/item.model';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../../core/shared/operators';
 import { ViewMode } from '../../../../core/shared/view-mode.model';
 import { hasValue, isNotEmpty } from '../../../../shared/empty.util';
 import { NgbModal, NgbModalRef } from '@ng-bootstrap/ng-bootstrap';
@@ -81,12 +81,12 @@ export class EditRelationshipComponent implements OnChanges {
   ngOnChanges(): void {
     if (this.relationship) {
       this.leftItem$ = this.relationship.leftItem.pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
         filter((item: Item) => hasValue(item) && isNotEmpty(item.uuid))
       );
       this.rightItem$ = this.relationship.rightItem.pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
         filter((item: Item) => hasValue(item) && isNotEmpty(item.uuid))
       );

src/app/+item-page/edit-item-page/item-relationships/item-relationships.component.spec.ts

@@ -11,7 +11,6 @@ import { EntityTypeService } from '../../../core/data/entity-type.service';
 import { ItemDataService } from '../../../core/data/item-data.service';
 import { FieldChangeType } from '../../../core/data/object-updates/object-updates.actions';
 import { ObjectUpdatesService } from '../../../core/data/object-updates/object-updates.service';
-import { PaginatedList } from '../../../core/data/paginated-list';
 import { RelationshipService } from '../../../core/data/relationship.service';
 import { RemoteData } from '../../../core/data/remote-data';
 import { RequestService } from '../../../core/data/request.service';
@@ -29,6 +28,8 @@ import { NotificationsService } from '../../../shared/notifications/notification
 import { SharedModule } from '../../../shared/shared.module';
 import { RouterStub } from '../../../shared/testing/router.stub';
 import { ItemRelationshipsComponent } from './item-relationships.component';
+import { createSuccessfulRemoteDataObject, createSuccessfulRemoteDataObject$ } from '../../../shared/remote-data.utils';
+import { createPaginatedList } from '../../../shared/testing/utils.test';
 
 let comp: any;
 let fixture: ComponentFixture<ItemRelationshipsComponent>;
@@ -84,7 +85,7 @@ describe('ItemRelationshipsComponent', () => {
         },
         id: '2',
         uuid: '2',
-        relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
+        relationshipType: createSuccessfulRemoteDataObject$(relationshipType)
       }),
       Object.assign(new Relationship(), {
         _links: {
@@ -92,7 +93,7 @@ describe('ItemRelationshipsComponent', () => {
         },
         id: '3',
         uuid: '3',
-        relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
+        relationshipType: createSuccessfulRemoteDataObject$(relationshipType)
       })
     ];
 
@@ -102,7 +103,7 @@ describe('ItemRelationshipsComponent', () => {
       },
       id: 'publication',
       uuid: 'publication',
-      relationships: observableOf(new RemoteData(false, false, true, undefined, new PaginatedList(new PageInfo(), relationships))),
+      relationships: createSuccessfulRemoteDataObject$(createPaginatedList(relationships)),
       lastModified: date
     });
 
@@ -119,10 +120,10 @@ describe('ItemRelationshipsComponent', () => {
       uuid: 'author2'
     });
 
-    relationships[0].leftItem = observableOf(new RemoteData(false, false, true, undefined, author1));
-    relationships[0].rightItem = observableOf(new RemoteData(false, false, true, undefined, item));
-    relationships[1].leftItem = observableOf(new RemoteData(false, false, true, undefined, author2));
-    relationships[1].rightItem = observableOf(new RemoteData(false, false, true, undefined, item));
+    relationships[0].leftItem = createSuccessfulRemoteDataObject$(author1);
+    relationships[0].rightItem = createSuccessfulRemoteDataObject$(item);
+    relationships[1].leftItem = createSuccessfulRemoteDataObject$(author2);
+    relationships[1].rightItem = createSuccessfulRemoteDataObject$(item);
 
     fieldUpdate1 = {
       field: relationships[0],
@@ -137,12 +138,12 @@ describe('ItemRelationshipsComponent', () => {
     };
 
     itemService = jasmine.createSpyObj('itemService', {
-      findById: observableOf(new RemoteData(false, false, true, undefined, item))
+      findById: createSuccessfulRemoteDataObject$(item)
     });
     routeStub = {
       data: observableOf({}),
       parent: {
-        data: observableOf({ dso: new RemoteData(false, false, true, null, item) })
+        data: observableOf({ dso: createSuccessfulRemoteDataObject(item) })
       }
     };
 
@@ -184,7 +185,7 @@ describe('ItemRelationshipsComponent', () => {
     requestService = jasmine.createSpyObj('requestService',
       {
         removeByHrefSubstring: {},
-        hasByHrefObservable: observableOf(false)
+        hasByHref$: observableOf(false)
       }
     );
 
@@ -194,20 +195,8 @@ describe('ItemRelationshipsComponent', () => {
 
     entityTypeService = jasmine.createSpyObj('entityTypeService',
       {
-        getEntityTypeByLabel: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          entityType,
-        )),
-        getEntityTypeRelationships: observableOf(new RemoteData(
-          false,
-          false,
-          true,
-          null,
-          new PaginatedList(new PageInfo(), [relationshipType]),
-        )),
+        getEntityTypeByLabel: createSuccessfulRemoteDataObject$(entityType),
+        getEntityTypeRelationships: createSuccessfulRemoteDataObject$(createPaginatedList([relationshipType])),
       }
     );
 

src/app/+item-page/edit-item-page/item-relationships/item-relationships.component.ts

@@ -1,4 +1,4 @@
-import { ChangeDetectorRef, Component, Inject, OnDestroy } from '@angular/core';
+import { ChangeDetectorRef, Component } from '@angular/core';
 import { Item } from '../../../core/shared/item.model';
 import {
   DeleteRelationship,
@@ -8,7 +8,11 @@ import {
 } from '../../../core/data/object-updates/object-updates.reducer';
 import { Observable } from 'rxjs/internal/Observable';
 import { filter, map, startWith, switchMap, take } from 'rxjs/operators';
-import { combineLatest as observableCombineLatest, of as observableOf, zip as observableZip} from 'rxjs';
+import {
+  combineLatest as observableCombineLatest,
+  of as observableOf,
+  zip as observableZip
+} from 'rxjs';
 import { followLink } from '../../../shared/utils/follow-link-config.model';
 import { AbstractItemUpdateComponent } from '../abstract-item-update/abstract-item-update.component';
 import { ItemDataService } from '../../../core/data/item-data.service';
@@ -17,16 +21,17 @@ import { ActivatedRoute, Router } from '@angular/router';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
 import { RelationshipService } from '../../../core/data/relationship.service';
-import { ErrorResponse, RestResponse } from '../../../core/cache/response.models';
 import { RemoteData } from '../../../core/data/remote-data';
 import { ObjectCacheService } from '../../../core/cache/object-cache.service';
-import { getRemoteDataPayload, getSucceededRemoteData } from '../../../core/shared/operators';
+import { getRemoteDataPayload, getFirstSucceededRemoteData } from '../../../core/shared/operators';
 import { RequestService } from '../../../core/data/request.service';
 import { RelationshipType } from '../../../core/shared/item-relationships/relationship-type.model';
 import { ItemType } from '../../../core/shared/item-relationships/item-type.model';
 import { EntityTypeService } from '../../../core/data/entity-type.service';
 import { FieldChangeType } from '../../../core/data/object-updates/object-updates.actions';
 import { Relationship } from '../../../core/shared/item-relationships/relationship.model';
+import { NoContent } from '../../../core/shared/NoContent.model';
+import { hasValue } from '../../../shared/empty.util';
 
 @Component({
   selector: 'ds-item-relationships',
@@ -78,10 +83,11 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
    * Update the item (and view) when it's removed in the request cache
    */
   public initializeItemUpdate(): void {
-    this.itemRD$ = this.requestService.hasByHrefObservable(this.item.self).pipe(
+    this.itemRD$ = this.requestService.hasByHref$(this.item.self).pipe(
       filter((exists: boolean) => !exists),
       switchMap(() => this.itemService.findById(
         this.item.uuid,
+        true,
         followLink('owningCollection'),
         followLink('bundles'),
         followLink('relationships')),
@@ -90,7 +96,7 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
     );
 
     this.itemRD$.pipe(
-      getSucceededRemoteData(),
+      getFirstSucceededRemoteData(),
       getRemoteDataPayload(),
     ).subscribe((item) => {
       this.item = item;
@@ -108,7 +114,7 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
     if (label !== undefined) {
 
       this.entityType$ = this.entityTypeService.getEntityTypeByLabel(label).pipe(
-        getSucceededRemoteData(),
+        getFirstSucceededRemoteData(),
         getRemoteDataPayload(),
       );
 
@@ -119,7 +125,7 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
             followLink('leftType'),
             followLink('rightType'))
             .pipe(
-              getSucceededRemoteData(),
+              getFirstSucceededRemoteData(),
               getRemoteDataPayload(),
               map((relationshipTypes) => relationshipTypes.page),
             )
@@ -162,6 +168,7 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
     const addRelatedItems$: Observable<RelationshipIdentifiable[]> = this.objectUpdatesService.getFieldUpdates(this.url, []).pipe(
       map((fieldUpdates: FieldUpdates) =>
         Object.values(fieldUpdates)
+          .filter((fieldUpdate: FieldUpdate) => hasValue(fieldUpdate))
           .filter((fieldUpdate: FieldUpdate) => fieldUpdate.changeType === FieldChangeType.ADD)
           .map((fieldUpdate: FieldUpdate) => fieldUpdate.field as RelationshipIdentifiable)
       ),
@@ -191,7 +198,7 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
     });
   }
 
-  deleteRelationships(deleteRelationshipIDs: DeleteRelationship[]): Observable<RestResponse[]> {
+  deleteRelationships(deleteRelationshipIDs: DeleteRelationship[]): Observable<Array<RemoteData<NoContent>>> {
     return observableZip(...deleteRelationshipIDs.map((deleteRelationship) => {
         let copyVirtualMetadata: string;
         if (deleteRelationship.keepLeftVirtualMetadata && deleteRelationship.keepRightVirtualMetadata) {
@@ -208,7 +215,7 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
     ));
   }
 
-  addRelationships(addRelatedItems: RelationshipIdentifiable[]): Observable<RestResponse[]> {
+  addRelationships(addRelatedItems: RelationshipIdentifiable[]): Observable<Array<RemoteData<Relationship>>> {
     return observableZip(...addRelatedItems.map((addRelationship) =>
       this.entityType$.pipe(
         switchMap((entityType) => this.entityTypeService.isLeftType(addRelationship.type, entityType)),
@@ -240,11 +247,11 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent {
    * - Success notification in case there's at least one successful response
    * @param responses
    */
-  displayNotifications(responses: RestResponse[]) {
-    const failedResponses = responses.filter((response: RestResponse) => !response.isSuccessful);
-    const successfulResponses = responses.filter((response: RestResponse) => response.isSuccessful);
+  displayNotifications(responses: Array<RemoteData<NoContent>>) {
+    const failedResponses = responses.filter((response: RemoteData<NoContent>) => response.hasFailed);
+    const successfulResponses = responses.filter((response: RemoteData<NoContent>) => response.hasSucceeded);
 
-    failedResponses.forEach((response: ErrorResponse) => {
+    failedResponses.forEach((response: RemoteData<NoContent>) => {
       this.notificationsService.error(this.getNotificationTitle('failed'), response.errorMessage);
     });
     if (successfulResponses.length > 0) {

src/app/+item-page/edit-item-page/item-version-history/item-version-history.component.ts

@@ -3,7 +3,7 @@ import { Observable } from 'rxjs/internal/Observable';
 import { RemoteData } from '../../../core/data/remote-data';
 import { Item } from '../../../core/shared/item.model';
 import { map } from 'rxjs/operators';
-import { getSucceededRemoteData } from '../../../core/shared/operators';
+import { getFirstSucceededRemoteData } from '../../../core/shared/operators';
 import { ActivatedRoute } from '@angular/router';
 import { AlertType } from '../../../shared/alert/aletr-type';
 
@@ -30,6 +30,6 @@ export class ItemVersionHistoryComponent {
   }
 
   ngOnInit(): void {
-    this.itemRD$ = this.route.parent.data.pipe(map((data) => data.dso)).pipe(getSucceededRemoteData()) as Observable<RemoteData<Item>>;
+    this.itemRD$ = this.route.parent.data.pipe(map((data) => data.dso)).pipe(getFirstSucceededRemoteData()) as Observable<RemoteData<Item>>;
   }
 }