tests and documentation

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

@@ -1,4 +1,5 @@
 import { Component, Inject } from '@angular/core';
+import { LinkService } from '../../../core/cache/builders/link.service';
 import { Item } from '../../../core/shared/item.model';
 import { ItemDataService } from '../../../core/data/item-data.service';
 import { ObjectUpdatesService } from '../../../core/data/object-updates/object-updates.service';

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

@@ -3,15 +3,18 @@ import { ComponentFixture, TestBed } from '@angular/core/testing';
 import { By } from '@angular/platform-browser';
 import { TranslateModule } from '@ngx-translate/core';
 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 { 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/mock-link-service';
 import { SharedModule } from '../../../../shared/shared.module';
 import { EditRelationshipListComponent } from './edit-relationship-list.component';
 
@@ -152,6 +155,8 @@ describe('EditRelationshipListComponent', () => {
       declarations: [EditRelationshipListComponent],
       providers: [
         { provide: ObjectUpdatesService, useValue: objectUpdatesService },
+        { provide: RelationshipTypeService, useValue: {} },
+        { provide: LinkService, useValue: getMockLinkService() },
       ], schemas: [
         NO_ERRORS_SCHEMA
       ]

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

@@ -1,15 +1,21 @@
 import { Component, Input, OnInit } from '@angular/core';
+import { LinkService } from '../../../../core/cache/builders/link.service';
 import { ObjectUpdatesService } from '../../../../core/data/object-updates/object-updates.service';
 import { Observable } from 'rxjs/internal/Observable';
 import {FieldUpdate, FieldUpdates} from '../../../../core/data/object-updates/object-updates.reducer';
 import {Item} from '../../../../core/shared/item.model';
-import {map, switchMap} from 'rxjs/operators';
+import { map, switchMap, tap } from 'rxjs/operators';
 import {hasValue} from '../../../../shared/empty.util';
 import {Relationship} from '../../../../core/shared/item-relationships/relationship.model';
 import {RelationshipType} from '../../../../core/shared/item-relationships/relationship-type.model';
-import {getRemoteDataPayload, getSucceededRemoteData} from '../../../../core/shared/operators';
-import {combineLatest as observableCombineLatest, combineLatest} from 'rxjs';
-import {ItemType} from '../../../../core/shared/item-relationships/item-type.model';
+import {
+  getAllSucceededRemoteData,
+  getRemoteDataPayload,
+  getSucceededRemoteData
+} from '../../../../core/shared/operators';
+import { combineLatest as observableCombineLatest } from 'rxjs';
+import { ItemType } from '../../../../core/shared/item-relationships/item-type.model';
+import { followLink } from '../../../../shared/utils/follow-link-config.model';
 
 @Component({
   selector: 'ds-edit-relationship-list',
@@ -47,6 +53,7 @@ export class EditRelationshipListComponent implements OnInit {
 
   constructor(
     protected objectUpdatesService: ObjectUpdatesService,
+    protected linkService: LinkService
   ) {
   }
 
@@ -71,7 +78,7 @@ export class EditRelationshipListComponent implements OnInit {
    */
   private getLabel(): Observable<string> {
 
-    return combineLatest([
+    return observableCombineLatest([
       this.relationshipType.leftType,
       this.relationshipType.rightType,
     ].map((itemTypeRD) => itemTypeRD.pipe(
@@ -94,8 +101,20 @@ export class EditRelationshipListComponent implements OnInit {
 
   ngOnInit(): void {
     this.updates$ = this.item.relationships.pipe(
+      getAllSucceededRemoteData(),
       map((relationships) => relationships.payload.page.filter((relationship) => relationship)),
-      switchMap((itemRelationships) =>
+      map((relationships: Relationship[]) =>
+        relationships.map((relationship: Relationship) => {
+          this.linkService.resolveLinks(
+            relationship,
+            followLink('relationshipType'),
+            followLink('leftItem'),
+            followLink('rightItem'),
+          );
+          return relationship;
+        })
+      ),
+      switchMap((itemRelationships: Relationship[]) =>
         observableCombineLatest(
           itemRelationships
             .map((relationship) => relationship.relationshipType.pipe(

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

@@ -26,6 +26,9 @@ import {
   INotification,
   Notification
 } from '../../../shared/notifications/models/notification.model';
+import { NotificationsService } from '../../../shared/notifications/notifications.service';
+import { SharedModule } from '../../../shared/shared.module';
+import { RouterStub } from '../../../shared/testing/router-stub';
 import { ItemRelationshipsComponent } from './item-relationships.component';
 
 let comp: any;

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

@@ -98,7 +98,11 @@ export class ItemRelationshipsComponent extends AbstractItemUpdateComponent impl
 
     this.relationshipTypes$ = this.entityType$.pipe(
       switchMap((entityType) =>
-        this.entityTypeService.getEntityTypeRelationships(entityType.id).pipe(
+        this.entityTypeService.getEntityTypeRelationships(
+          entityType.id,
+          followLink('leftType'),
+          followLink('rightType'))
+        .pipe(
           getSucceededRemoteData(),
           getRemoteDataPayload(),
           map((relationshipTypes) => relationshipTypes.page),

src/app/core/auth/auth.service.spec.ts

@@ -5,6 +5,7 @@ import { ActivatedRoute, Router } from '@angular/router';
 import { Store, StoreModule } from '@ngrx/store';
 import { REQUEST } from '@nguniversal/express-engine/tokens';
 import { of as observableOf } from 'rxjs';
+import { LinkService } from '../cache/builders/link.service';
 
 import { authReducer, AuthState } from './auth.reducer';
 import { NativeWindowRef, NativeWindowService } from '../services/window.service';
@@ -38,7 +39,7 @@ describe('AuthService test', () => {
   let storage: CookieService;
   let token: AuthTokenInfo;
   let authenticatedState;
-  let rdbService;
+  let linkService;
 
   function init() {
     mockStore = jasmine.createSpyObj('store', {
@@ -58,8 +59,10 @@ describe('AuthService test', () => {
     };
     authRequest = new AuthRequestServiceStub();
     routeStub = new ActivatedRouteStub();
-    rdbService = getMockRemoteDataBuildService();
-    spyOn(rdbService, 'build').and.returnValue({authenticated: true, eperson: observableOf({payload: {}})});
+    linkService = {
+      resolveLinks: {}
+    };
+    spyOn(linkService, 'resolveLinks').and.returnValue({authenticated: true, eperson: observableOf({payload: {}})});
 
   }
 
@@ -80,7 +83,7 @@ describe('AuthService test', () => {
           { provide: RouteService, useValue: routeServiceStub },
           { provide: ActivatedRoute, useValue: routeStub },
           { provide: Store, useValue: mockStore },
-          { provide: RemoteDataBuildService, useValue: rdbService },
+          { provide: LinkService, useValue: linkService },
           CookieService,
           AuthService
         ],
@@ -143,7 +146,7 @@ describe('AuthService test', () => {
           { provide: REQUEST, useValue: {} },
           { provide: Router, useValue: routerStub },
           { provide: RouteService, useValue: routeServiceStub },
-          { provide: RemoteDataBuildService, useValue: rdbService },
+          { provide: RemoteDataBuildService, useValue: linkService },
           CookieService,
           AuthService
         ]
@@ -156,7 +159,7 @@ describe('AuthService test', () => {
           (state as any).core = Object.create({});
           (state as any).core.auth = authenticatedState;
         });
-      authService = new AuthService({}, window, undefined, authReqService, router, routeService, cookieService, store, rdbService);
+      authService = new AuthService({}, window, undefined, authReqService, router, routeService, cookieService, store, linkService);
     }));
 
     it('should return true when user is logged in', () => {
@@ -195,7 +198,7 @@ describe('AuthService test', () => {
           { provide: REQUEST, useValue: {} },
           { provide: Router, useValue: routerStub },
           { provide: RouteService, useValue: routeServiceStub },
-          { provide: RemoteDataBuildService, useValue: rdbService },
+          { provide: RemoteDataBuildService, useValue: linkService },
           ClientCookieService,
           CookieService,
           AuthService
@@ -218,7 +221,7 @@ describe('AuthService test', () => {
           (state as any).core = Object.create({});
           (state as any).core.auth = authenticatedState;
         });
-      authService = new AuthService({}, window, undefined, authReqService, router, routeService, cookieService, store, rdbService);
+      authService = new AuthService({}, window, undefined, authReqService, router, routeService, cookieService, store, linkService);
       storage = (authService as any).storage;
       routeServiceMock = TestBed.get(RouteService);
       routerStub = TestBed.get(Router);

src/app/core/auth/auth.service.ts

@@ -9,6 +9,7 @@ import { RouterReducerState } from '@ngrx/router-store';
 import { select, Store } from '@ngrx/store';
 import { CookieAttributes } from 'js-cookie';
 import { followLink } from '../../shared/utils/follow-link-config.model';
+import { LinkService } from '../cache/builders/link.service';
 
 import { EPerson } from '../eperson/models/eperson.model';
 import { AuthRequestService } from './auth-request.service';
@@ -22,8 +23,7 @@ import { AppState, routerStateSelector } from '../../app.reducer';
 import { ResetAuthenticationMessagesAction, SetRedirectUrlAction } from './auth.actions';
 import { NativeWindowRef, NativeWindowService } from '../services/window.service';
 import { Base64EncodeUrl } from '../../shared/utils/encode-decode.util';
-import { RemoteDataBuildService } from '../cache/builders/remote-data-build.service';
-import {RouteService} from '../services/route.service';
+import { RouteService } from '../services/route.service';
 
 export const LOGIN_ROUTE = '/login';
 export const LOGOUT_ROUTE = '/logout';
@@ -50,7 +50,7 @@ export class AuthService {
               protected routeService: RouteService,
               protected storage: CookieService,
               protected store: Store<AppState>,
-              protected rdbService: RemoteDataBuildService
+              protected linkService: LinkService
   ) {
     this.store.pipe(
       select(isAuthenticated),
@@ -134,7 +134,7 @@ export class AuthService {
     headers = headers.append('Authorization', `Bearer ${token.accessToken}`);
     options.headers = headers;
     return this.authRequestService.getRequest('status', options).pipe(
-      map((status) => this.rdbService.build(status, followLink<AuthStatus>('eperson'))),
+      map((status) => this.linkService.resolveLinks(status, followLink<AuthStatus>('eperson'))),
       switchMap((status: AuthStatus) => {
         if (status.authenticated) {
           return status.eperson.pipe(map((eperson) => eperson.payload));

src/app/core/auth/server-auth.service.ts

@@ -35,7 +35,7 @@ export class ServerAuthService extends AuthService {
 
     options.headers = headers;
     return this.authRequestService.getRequest('status', options).pipe(
-      map((status) => this.rdbService.build(status, followLink<AuthStatus>('eperson'))),
+      map((status) => this.linkService.resolveLinks(status, followLink<AuthStatus>('eperson'))),
       switchMap((status: AuthStatus) => {
         if (status.authenticated) {
           return status.eperson.pipe(map((eperson) => eperson.payload));

src/app/core/cache/builders/build-decorators.ts

@@ -33,6 +33,15 @@ export function getClassForType(type: string | ResourceType) {
   return typeMap.get(type);
 }
 
+/**
+ * A class decorator to indicate that this class is a dataservice
+ * for a given resource type.
+ *
+ * "dataservice" in this context means that it has findByHref and
+ * findAllByHref methods.
+ *
+ * @param resourceType the resource type the class is a dataservice for
+ */
 export function dataService(resourceType: ResourceType): any {
   return (target: any) => {
     if (hasNoValue(resourceType)) {
@@ -48,6 +57,11 @@ export function dataService(resourceType: ResourceType): any {
   };
 }
 
+/**
+ * Return the dataservice matching the given resource type
+ *
+ * @param resourceType the resource type you want the matching dataservice for
+ */
 export function getDataServiceFor<T extends CacheableObject>(resourceType: ResourceType) {
   return dataServiceMap.get(resourceType.value);
 }
@@ -71,6 +85,9 @@ export function resolvedLink<T extends DataService<any>, K extends keyof T>(prov
   };
 }
 
+/**
+ * A class to represent the data that can be set by the @link decorator
+ */
 export class LinkDefinition<T extends HALResource> {
   resourceType: ResourceType;
   isList = false;
@@ -78,6 +95,19 @@ export class LinkDefinition<T extends HALResource> {
   propertyName: keyof T;
 }
 
+/**
+ * A property decorator to indicate that a certain property is the placeholder
+ * where the contents of a resolved link should be stored.
+ *
+ * e.g. if an Item has an hal link for bundles, and an item.bundles property
+ * this decorator should decorate that item.bundles property.
+ *
+ * @param resourceType the resource type of the object(s) the link retrieves
+ * @param isList an optional boolean indicating whether or not it concerns a list,
+ * defaults to false
+ * @param linkName an optional string in case the HALLink name differs from the
+ * property name
+ */
 export const link = <T extends HALResource>(
   resourceType: ResourceType,
   isList = false,
@@ -105,10 +135,20 @@ export const link = <T extends HALResource>(
   }
 };
 
+/**
+ * Returns all LinkDefinitions for a model class
+ * @param source
+ */
 export const getLinkDefinitions = <T extends HALResource>(source: GenericConstructor<T>): Map<keyof T['_links'], LinkDefinition<T>> => {
   return linkMap.get(source);
 };
 
+/**
+ * Returns a specific LinkDefinition for a model class
+ *
+ * @param source the model class
+ * @param linkName the name of the link
+ */
 export const getLinkDefinition = <T extends HALResource>(source: GenericConstructor<T>, linkName: keyof T['_links']): LinkDefinition<T> => {
   const sourceMap = linkMap.get(source);
   if (hasValue(sourceMap)) {
@@ -118,6 +158,12 @@ export const getLinkDefinition = <T extends HALResource>(source: GenericConstruc
   }
 };
 
+/**
+ * A class level decorator to indicate you want to inherit @link annotations
+ * from a parent class.
+ *
+ * @param parent the parent class to inherit @link annotations from
+ */
 export const inheritLinkAnnotations = (parent: any): any => {
   return (child: any) => {
     const parentMap: Map<string, LinkDefinition<any>> = linkMap.get(parent) || new Map();

src/app/core/cache/builders/link.service.spec.ts

@@ -0,0 +1,222 @@
+import { Injectable } from '@angular/core';
+import { TestBed } from '@angular/core/testing';
+import { followLink, FollowLinkConfig } from '../../../shared/utils/follow-link-config.model';
+import { FindListOptions } from '../../data/request.models';
+import { HALLink } from '../../shared/hal-link.model';
+import { HALResource } from '../../shared/hal-resource.model';
+import { ResourceType } from '../../shared/resource-type';
+import * as decorators from './build-decorators';
+import { getDataServiceFor } from './build-decorators';
+import { LinkService } from './link.service';
+
+const spyOnFunction = <T>(obj: T, func: keyof T) => {
+  const spy = jasmine.createSpy(func as string);
+  spyOnProperty(obj, func, 'get').and.returnValue(spy);
+
+  return spy;
+};
+
+const TEST_MODEL = new ResourceType('testmodel');
+let result: any;
+
+/* tslint:disable:max-classes-per-file */
+class TestModel implements HALResource {
+  static type = TEST_MODEL;
+
+  type = TEST_MODEL;
+
+  value: string;
+
+  _links: {
+    self: HALLink;
+    predecessor: HALLink;
+    successor: HALLink;
+  };
+
+  predecessor?: TestModel;
+  successor?: TestModel;
+}
+
+@Injectable()
+class TestDataService {
+  findAllByHref(href: string, findListOptions: FindListOptions = {}, ...linksToFollow: Array<FollowLinkConfig<any>>) {
+    return 'findAllByHref'
+  }
+  findByHref(href: string, ...linksToFollow: Array<FollowLinkConfig<any>>) {
+    return 'findByHref'
+  }
+}
+
+let testDataService: TestDataService;
+
+let testModel: TestModel;
+
+describe('LinkService', () => {
+  let service: LinkService;
+
+  beforeEach(() => {
+    testModel = Object.assign(new TestModel(), {
+      value: 'a test value',
+      _links: {
+        self: {
+          href: 'http://self.link'
+        },
+        predecessor: {
+          href: 'http://predecessor.link'
+        },
+        successor: {
+          href: 'http://successor.link'
+        },
+      }
+    });
+    testDataService = new TestDataService();
+    spyOn(testDataService, 'findAllByHref').and.callThrough();
+    spyOn(testDataService, 'findByHref').and.callThrough();
+    TestBed.configureTestingModule({
+      providers: [LinkService, {
+        provide: TestDataService,
+        useValue: testDataService
+      }]
+    });
+    service = TestBed.get(LinkService);
+  });
+
+  describe('resolveLink', () => {
+    describe(`when the linkdefinition concerns a single object`, () => {
+      beforeEach(() => {
+        spyOnFunction(decorators, 'getLinkDefinition').and.returnValue({
+          resourceType: TEST_MODEL,
+          linkName: 'predecessor',
+          propertyName: 'predecessor'
+        });
+        spyOnFunction(decorators, 'getDataServiceFor').and.returnValue(TestDataService);
+        service.resolveLink(testModel, followLink('predecessor', {}, followLink('successor')))
+      });
+      it('should call dataservice.findByHref with the correct href and nested links', () => {
+        expect(testDataService.findByHref).toHaveBeenCalledWith(testModel._links.predecessor.href, followLink('successor'));
+      });
+    });
+    describe(`when the linkdefinition concerns a list`, () => {
+      beforeEach(() => {
+        spyOnFunction(decorators, 'getLinkDefinition').and.returnValue({
+          resourceType: TEST_MODEL,
+          linkName: 'predecessor',
+          propertyName: 'predecessor',
+          isList: true
+        });
+        spyOnFunction(decorators, 'getDataServiceFor').and.returnValue(TestDataService);
+        service.resolveLink(testModel, followLink('predecessor', { some: 'options '} as any, followLink('successor')))
+      });
+      it('should call dataservice.findAllByHref with the correct href, findListOptions,  and nested links', () => {
+        expect(testDataService.findAllByHref).toHaveBeenCalledWith(testModel._links.predecessor.href, { some: 'options '} as any, followLink('successor'));
+      });
+    });
+    describe('either way', () => {
+      beforeEach(() => {
+        spyOnFunction(decorators, 'getLinkDefinition').and.returnValue({
+          resourceType: TEST_MODEL,
+          linkName: 'predecessor',
+          propertyName: 'predecessor'
+        });
+        spyOnFunction(decorators, 'getDataServiceFor').and.returnValue(TestDataService);
+        result = service.resolveLink(testModel, followLink('predecessor', {}, followLink('successor')))
+      });
+
+      it('should call getLinkDefinition with the correct model and link', () => {
+        expect(decorators.getLinkDefinition).toHaveBeenCalledWith(testModel.constructor, 'predecessor');
+      });
+
+      it('should call getDataServiceFor with the correct resource type', () => {
+        expect(decorators.getDataServiceFor).toHaveBeenCalledWith(TEST_MODEL);
+      });
+
+      it('should return the model with the resolved link', () => {
+        expect(result.type).toBe(TEST_MODEL);
+        expect(result.value).toBe('a test value');
+        expect(result._links.self.href).toBe('http://self.link');
+        expect(result.predecessor).toBe('findByHref');
+      });
+    });
+
+    describe(`when the specified link doesn't exist on the model's class`, () => {
+      beforeEach(() => {
+        spyOnFunction(decorators, 'getLinkDefinition').and.returnValue(undefined);
+      });
+      it('should throw an error', () => {
+        expect(() => {
+          service.resolveLink(testModel, followLink('predecessor', {}, followLink('successor')))
+        }).toThrow();
+      });
+    });
+
+    describe(`when there is no dataservice for the resourcetype in the link`, () => {
+      beforeEach(() => {
+        spyOnFunction(decorators, 'getLinkDefinition').and.returnValue({
+          resourceType: TEST_MODEL,
+          linkName: 'predecessor',
+          propertyName: 'predecessor'
+        });
+        spyOnFunction(decorators, 'getDataServiceFor').and.returnValue(undefined);
+      });
+      it('should throw an error', () => {
+        expect(() => {
+          service.resolveLink(testModel, followLink('predecessor', {}, followLink('successor')))
+        }).toThrow();
+      });
+    });
+  });
+
+  describe('resolveLinks', () => {
+    beforeEach(() => {
+      spyOn(service, 'resolveLink');
+      service.resolveLinks(testModel, followLink('predecessor'), followLink('successor'))
+    });
+
+    it('should call resolveLink with the model for each of the provided links', () => {
+      expect(service.resolveLink).toHaveBeenCalledWith(testModel, followLink('predecessor'));
+      expect(service.resolveLink).toHaveBeenCalledWith(testModel, followLink('successor'));
+    });
+
+    it('should return the model', () => {
+      expect(result.type).toBe(TEST_MODEL);
+      expect(result.value).toBe('a test value');
+      expect(result._links.self.href).toBe('http://self.link');
+    });
+  });
+
+  describe('removeResolvedLinks', () => {
+    beforeEach(() => {
+      testModel.predecessor = 'predecessor value';
+      testModel.successor = 'successor value';
+      spyOnFunction(decorators, 'getLinkDefinitions').and.returnValue([
+        {
+          resourceType: TEST_MODEL,
+          linkName: 'predecessor',
+          propertyName: 'predecessor',
+        },
+        {
+          resourceType: TEST_MODEL,
+          linkName: 'successor',
+          propertyName: 'successor',
+        }
+      ])
+    });
+
+    it('should return a new version of the object without any resolved links', () => {
+      result = service.removeResolvedLinks(testModel);
+      expect(result.value).toBe(testModel.value);
+      expect(result.type).toBe(testModel.type);
+      expect(result._links).toBe(testModel._links);
+      expect(result.predecessor).toBeUndefined();
+      expect(result.successor).toBeUndefined();
+    });
+
+    it('should leave the original object untouched', () => {
+      service.removeResolvedLinks(testModel);
+      expect(testModel.predecessor).toBe('predecessor value');
+      expect(testModel.successor).toBe('successor value');
+    });
+  });
+
+});
+/* tslint:enable:max-classes-per-file */

src/app/core/cache/builders/link.service.ts

@@ -5,6 +5,10 @@ import { GenericConstructor } from '../../shared/generic-constructor';
 import { HALResource } from '../../shared/hal-resource.model';
 import { getDataServiceFor, getLinkDefinition, getLinkDefinitions, LinkDefinition } from './build-decorators';
 
+/**
+ * A Service to handle the resolving and removing
+ * of resolved HALLinks on HALResources
+ */
 @Injectable({
   providedIn: 'root'
 })
@@ -15,13 +19,26 @@ export class LinkService {
   ) {
   }
 
-  public resolveLinks<T extends HALResource>(model: T, ...linksToFollow: Array<FollowLinkConfig<T>>) {
+  /**
+   * Resolve the given {@link FollowLinkConfig}s for the given model
+   *
+   * @param model the {@link HALResource} to resolve the links for
+   * @param linksToFollow the {@link FollowLinkConfig}s to resolve
+   */
+  public resolveLinks<T extends HALResource>(model: T, ...linksToFollow: Array<FollowLinkConfig<T>>): T {
     linksToFollow.forEach((linkToFollow: FollowLinkConfig<T>) => {
       this.resolveLink(model, linkToFollow);
     });
+    return model;
   }
 
-  public resolveLink<T extends HALResource>(model, linkToFollow: FollowLinkConfig<T>) {
+  /**
+   * Resolve the given {@link FollowLinkConfig} for the given model
+   *
+   * @param model the {@link HALResource} to resolve the link for
+   * @param linkToFollow the {@link FollowLinkConfig} to resolve
+   */
+  public resolveLink<T extends HALResource>(model, linkToFollow: FollowLinkConfig<T>): T {
     const matchingLinkDef = getLinkDefinition(model.constructor, linkToFollow.name);
 
     if (hasNoValue(matchingLinkDef)) {
@@ -50,10 +67,14 @@ export class LinkService {
         throw new Error(`Something went wrong when using @dataService(${matchingLinkDef.resourceType.value}) ${hasValue(service) ? '' : '(undefined) '}to resolve link ${linkToFollow.name} from ${href}`);
       }
     }
+    return model;
   }
 
   /**
    * Remove any resolved links that the model may have.
+   *
+   * @param model the {@link HALResource} to remove the links from
+   * @returns a copy of the given model, without resolved links.
    */
   public removeResolvedLinks<T extends HALResource>(model: T): T {
     const result = Object.assign(new (model.constructor as GenericConstructor<T>)(), model);

src/app/core/cache/builders/remote-data-build.service.ts

@@ -80,9 +80,9 @@ export class RemoteDataBuildService {
           }
         }),
         hasValueOperator(),
-        map((obj: T) => {
-          return this.build<T>(obj, ...linksToFollow);
-        }),
+        map((obj: T) =>
+          this.linkService.resolveLinks(obj, ...linksToFollow)
+        ),
         startWith(undefined),
         distinctUntilChanged()
       );
@@ -135,9 +135,9 @@ export class RemoteDataBuildService {
       switchMap((resourceUUIDs: string[]) => {
         return this.objectCache.getList(resourceUUIDs).pipe(
           map((objs: T[]) => {
-            return objs.map((obj: T) => {
-              return this.build<T>(obj, ...linksToFollow);
-            });
+            return objs.map((obj: T) =>
+              this.linkService.resolveLinks(obj, ...linksToFollow)
+            );
           }));
       }),
       startWith([]),
@@ -166,11 +166,6 @@ export class RemoteDataBuildService {
     return this.toRemoteDataObservable(requestEntry$, payload$);
   }
 
-  build<T extends CacheableObject>(model: T, ...linksToFollow: Array<FollowLinkConfig<T>>): T {
-    this.linkService.resolveLinks(model, ...linksToFollow);
-    return model;
-  }
-
   aggregate<T>(input: Array<Observable<RemoteData<T>>>): Observable<RemoteData<T[]>> {
 
     if (isEmpty(input)) {

src/app/core/data/entity-type.service.ts

@@ -1,7 +1,7 @@
+import { FollowLinkConfig } from '../../shared/utils/follow-link-config.model';
 import { DataService } from './data.service';
 import { RequestService } from './request.service';
 import { RemoteDataBuildService } from '../cache/builders/remote-data-build.service';
-import { NormalizedObjectBuildService } from '../cache/builders/normalized-object-build.service';
 import { Store } from '@ngrx/store';
 import { CoreState } from '../core.reducers';
 import { HALEndpointService } from '../shared/hal-endpoint.service';
@@ -25,11 +25,9 @@ import {ItemType} from '../shared/item-relationships/item-type.model';
 export class EntityTypeService extends DataService<ItemType> {
 
   protected linkPath = 'entitytypes';
-  protected forceBypassCache = false;
 
   constructor(protected requestService: RequestService,
               protected rdbService: RemoteDataBuildService,
-              protected dataBuildService: NormalizedObjectBuildService,
               protected store: Store<CoreState>,
               protected halService: HALEndpointService,
               protected objectCache: ObjectCacheService,
@@ -56,8 +54,9 @@ export class EntityTypeService extends DataService<ItemType> {
   /**
    * Get the allowed relationship types for an entity type
    * @param entityTypeId
+   * @param linksToFollow     List of {@link FollowLinkConfig} that indicate which HALLinks should be automatically resolved
    */
-  getEntityTypeRelationships(entityTypeId: string): Observable<RemoteData<PaginatedList<RelationshipType>>> {
+  getEntityTypeRelationships(entityTypeId: string, ...linksToFollow: Array<FollowLinkConfig<RelationshipType>>): Observable<RemoteData<PaginatedList<RelationshipType>>> {
 
     const href$ = this.getRelationshipTypesEndpoint(entityTypeId);
 
@@ -66,7 +65,7 @@ export class EntityTypeService extends DataService<ItemType> {
       this.requestService.configure(request);
     });
 
-    return this.rdbService.buildList(href$);
+    return this.rdbService.buildList(href$, ...linksToFollow);
   }
 
   /**

src/app/core/data/relationship.service.spec.ts

@@ -33,25 +33,6 @@ describe('RelationshipService', () => {
     rightwardType: 'isPublicationOfAuthor'
   });
 
-  const relationship1 = Object.assign(new Relationship(), {
-    _links: {
-      self: { href: relationshipsEndpointURL + '/2' }
-    },
-    id: '2',
-    uuid: '2',
-    relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
-  });
-  const relationship2 = Object.assign(new Relationship(), {
-    _links: {
-      self: { href: relationshipsEndpointURL + '/3' }
-    },
-    id: '3',
-    uuid: '3',
-    relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
-  });
-
-  const relationships = [relationship1, relationship2];
-
   const item = Object.assign(new Item(), {
     id: 'publication',
     uuid: 'publication',
@@ -76,6 +57,42 @@ describe('RelationshipService', () => {
       self: { href: restEndpointURL + '/author2' }
     }
   });
+
+  const relationship1 = Object.assign(new Relationship(), {
+    _links: {
+      self: {
+        href: relationshipsEndpointURL + '/2'
+      },
+      leftItem: {
+        href: relatedItem1._links.self.href
+      },
+      rightItem: {
+        href: item._links.self.href
+      }
+    },
+    id: '2',
+    uuid: '2',
+    relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
+  });
+  const relationship2 = Object.assign(new Relationship(), {
+    _links: {
+      self: {
+        href: relationshipsEndpointURL + '/3'
+      },
+      leftItem: {
+        href: relatedItem2._links.self.href
+      },
+      rightItem: {
+        href: item._links.self.href
+     },
+    },
+    id: '3',
+    uuid: '3',
+    relationshipType: observableOf(new RemoteData(false, false, true, undefined, relationshipType))
+  });
+
+  const relationships = [relationship1, relationship2];
+
   relationship1.leftItem = getRemotedataObservable(relatedItem1);
   relationship1.rightItem = getRemotedataObservable(item);
   relationship2.leftItem = getRemotedataObservable(relatedItem2);

src/app/core/data/relationship.service.ts

@@ -446,19 +446,12 @@ export class RelationshipService extends DataService<Relationship> {
   clearRelatedCache(uuid: string): Observable<void> {
     return this.findById(uuid).pipe(
       getSucceededRemoteData(),
-      switchMap((rd: RemoteData<Relationship>) =>
-        observableCombineLatest(
-          rd.payload.leftItem.pipe(getSucceededRemoteData()),
-          rd.payload.rightItem.pipe(getSucceededRemoteData())
-        )
-      ),
-      take(1),
-      map(([leftItem, rightItem]) => {
-        this.objectCache.remove(leftItem.payload.self);
-        this.objectCache.remove(rightItem.payload.self);
-        this.requestService.removeByHrefSubstring(leftItem.payload.self);
-        this.requestService.removeByHrefSubstring(rightItem.payload.self);
-      }),
+      map((rd: RemoteData<Relationship>) => {
+        this.objectCache.remove(rd.payload._links.leftItem.href);
+        this.objectCache.remove(rd.payload._links.rightItem.href);
+        this.requestService.removeByHrefSubstring(rd.payload._links.leftItem.href);
+        this.requestService.removeByHrefSubstring(rd.payload._links.rightItem.href);
+      })
     );
   }
 }

src/app/core/shared/item.model.ts

@@ -87,7 +87,7 @@ export class Item extends DSpaceObject {
    * The list of Relationships this Item has with others
    * Will be undefined unless the relationships HALLink has been resolved.
    */
-  @link(RELATIONSHIP)
+  @link(RELATIONSHIP, true)
   relationships?: Observable<RemoteData<PaginatedList<Relationship>>>;
 
   /**

src/app/core/shared/search/search.service.ts

@@ -342,8 +342,7 @@ export class SearchService implements OnDestroy {
       switchMap((dsoRD: RemoteData<DSpaceObject>) => {
           if ((dsoRD.payload as any).type === Community.type.value) {
             const community: Community = dsoRD.payload as Community;
-            this.linkService.resolveLink(community, followLink('subcommunities'));
-            this.linkService.resolveLink(community, followLink('collections'));
+            this.linkService.resolveLinks(community, followLink('subcommunities'), followLink('collections'));
             return observableCombineLatest(community.subcommunities, community.collections).pipe(
               map(([subCommunities, collections]) => {
                 /*if this is a community, we also need to show the direct children*/

src/app/shared/mocks/mock-remote-data-build.service.ts

@@ -21,7 +21,6 @@ export function getMockRemoteDataBuildService(toRemoteDataObservable$?: Observab
       }
     },
     buildSingle: (href$: string | Observable<string>) => createSuccessfulRemoteDataObject$({}),
-    build: (obj: any) => Object.create({}),
     buildList: (href$: string | Observable<string>) => {
       if (hasValue(buildList$)) {
         return buildList$;
@@ -46,7 +45,6 @@ export function getMockRemoteDataBuildServiceHrefMap(toRemoteDataObservable$?: O
       }
     },
     buildSingle: (href$: string | Observable<string>) => createSuccessfulRemoteDataObject$({}),
-    build: (obj: any) => Object.create({}),
     buildList: (href$: string | Observable<string>) => {
       if (typeof href$ === 'string') {
         if (hasValue(buildListHrefMap$[href$])) {

src/app/shared/utils/follow-link-config.model.ts

@@ -1,12 +1,42 @@
 import { FindListOptions } from '../../core/data/request.models';
 import { HALResource } from '../../core/shared/hal-resource.model';
 
+/**
+ * A class to configure the retrieval of a HALLink
+ */
 export class FollowLinkConfig<R extends HALResource> {
+  /**
+   * The name of the link to fetch.
+   * Can only be a HALLink of the object you're working with
+   */
   name: keyof R['_links'];
+
+  /**
+   * {@link FindListOptions} for the query,
+   * allows you to resolve the link using a certain page, or sorted
+   * in a certain way
+   */
   findListOptions?: FindListOptions;
+
+  /**
+   * A list of {@link FollowLinkConfig}s to
+   * use on the retrieved object.
+   */
   linksToFollow?: Array<FollowLinkConfig<any>>;
 }
 
+/**
+ * A factory function for {@link FollowLinkConfig}s,
+ * in order to create them in a less verbose way.
+ *
+ * @param linkName: the name of the link to fetch.
+ * Can only be a HALLink of the object you're working with
+ * @param findListOptions: {@link FindListOptions} for the query,
+ * allows you to resolve the link using a certain page, or sorted
+ * in a certain way
+ * @param linksToFollow: a list of {@link FollowLinkConfig}s to
+ * use on the retrieved object.
+ */
 export const followLink = <R extends HALResource>(
   linkName: keyof R['_links'],
   findListOptions?: FindListOptions,