68346: initial Drag-And-Drop pagination component + paginated custom-order support in field-updates store - Intermediate commit

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

@@ -13,7 +13,7 @@
 .row-element {
   padding: 12px;
   padding: 0.75em;
-  border-top: $table-border-width solid $table-border-color;
+  border-bottom: $table-border-width solid $table-border-color;
 }
 
 .drag-handle {

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

@@ -17,7 +17,15 @@
       </div>
     </div>
   </div>
-  <div [id]="bundle.id" class="bundle-bitstreams-list" *ngVar="((updates$ | async) | dsObjectValues) as updateValues" cdkDropList (cdkDropListDropped)="drop($event)">
+  <ds-pagination-drag-and-drop  [paginationOptions]="bitstreamsOptions"
+                                [paginatedList]="(bitstreamsRD$ | async)?.payload"
+                                [hideGear]="true"
+                                [hidePaginationDetail]="true"
+                                [disableRouteParameterUpdate]="true"
+                                (pageChange)="switchPage($event)">
+    <div [id]="bundle.id" class="bundle-bitstreams-list"
+         [ngClass]="{'mb-3': (bitstreamsRD$ | async)?.payload?.totalElements > batchSize}"
+         *ngVar="((updates$ | async) | dsObjectValues) as updateValues" cdkDropList (cdkDropListDropped)="drop($event)">
       <div class="row bitstream-row" *ngFor="let updateValue of updateValues" cdkDrag
            [ngClass]="{
                   'table-warning': updateValue.changeType === 0,
@@ -30,22 +38,6 @@
           <ds-item-edit-bitstream-drag-handle slot="drag-handle"></ds-item-edit-bitstream-drag-handle>
         </ds-item-edit-bitstream>
       </div>
-    <ng-container *ngVar="(bitstreamsRD$ | async) as bitstreamsRD">
-      <div class="row" *ngIf="bitstreamsRD?.payload?.elementsPerPage < bitstreamsRD?.payload?.totalElements">
-        <ng-container *ngVar="(isLoadingMore$ | async) as loading">
-          <div class="col-6 col-sm-7 col-md-8 col-lg-9 row-element" *ngIf="!loading">
-            <span class="font-italic">{{'item.edit.bitstreams.bundle.displaying' | translate:{ amount: bitstreamsRD?.payload?.elementsPerPage, total: bitstreamsRD?.payload?.totalElements } }}</span>
-          </div>
-          <div class="col-6 col-sm-5 col-md-4 col-lg-3 row-element text-center" *ngIf="!loading">
-            <a [routerLink]="[]" (click)="loadMore()">{{'item.edit.bitstreams.bundle.load.more' | translate}}</a>
-            <span> | </span>
-            <a [routerLink]="[]" (click)="loadAll()">{{'item.edit.bitstreams.bundle.load.all' | translate:{ total: bitstreamsRD?.payload?.totalElements } }}</a>
-          </div>
-          <div class="col-12 row-element text-center" *ngIf="loading">
-            <span class="font-italic">{{'loading.bitstreams' | translate}}</span>
-          </div>
-        </ng-container>
-      </div>
-    </ng-container>
     </div>
+  </ds-pagination-drag-and-drop>
 </ng-template>

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

@@ -13,8 +13,9 @@ import { PaginatedList } from '../../../../core/data/paginated-list';
 import { BundleDataService } from '../../../../core/data/bundle-data.service';
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
 import { combineLatest as observableCombineLatest } from 'rxjs';
-import { hasNoValue } from '../../../../shared/empty.util';
+import { hasNoValue, isEmpty } from '../../../../shared/empty.util';
 import { PaginatedSearchOptions } from '../../../../shared/search/paginated-search-options.model';
+import { PaginationComponentOptions } from '../../../../shared/pagination/pagination-component-options.model';
 
 @Component({
   selector: 'ds-item-edit-bitstream-bundle',
@@ -55,33 +56,26 @@ export class ItemEditBitstreamBundleComponent implements OnInit {
    * The amount of one bitstreams one "batch" resembles
    * The user is able to increase the amount of bitstreams displayed per bundle by this batch size until all are shown
    */
-  batchSize = 10;
+  batchSize = 2;
 
   /**
    * The page options to use for fetching the bitstreams
    */
-  bitstreamsOptions = {
+  bitstreamsOptions = Object.assign(new PaginationComponentOptions(),{
     id: 'bitstreams-pagination-options',
     currentPage: 1,
     pageSize: this.batchSize
-  } as any;
+  });
 
   /**
-   * The current amount of bitstreams to display for this bundle
+   * The current page we're displaying for this bundle
-   * Starts off with just one batch
    */
-  currentSize$ = new BehaviorSubject<number>(this.batchSize);
+  currentPage$ = new BehaviorSubject<number>(1);
 
   /**
-   * Are we currently loading more bitstreams?
+   * A list of pages that have been initialized in the field-update store
    */
-  isLoadingMore$: Observable<boolean>;
+  initializedPages: number[] = [];
-
-  /**
-   * What size were the object updates last initialized with?
-   * Used to check if the object updates need to be re-initialized when loading more bitstreams
-   */
-  lastInitializedWithSize: number;
 
   constructor(private objectUpdatesService: ObjectUpdatesService,
               private bundleService: BundleDataService,
@@ -89,27 +83,39 @@ export class ItemEditBitstreamBundleComponent implements OnInit {
   }
 
   ngOnInit(): void {
-    this.bitstreamsRD$ = this.currentSize$.pipe(
+    this.bitstreamsRD$ = this.currentPage$.pipe(
-      switchMap((size: number) => this.bundleService.getBitstreams(this.bundle.id,
+      switchMap((page: number) => this.bundleService.getBitstreams(this.bundle.id,
-        new PaginatedSearchOptions({pagination: Object.assign({}, this.bitstreamsOptions, { pageSize: size })})))
+        new PaginatedSearchOptions({pagination: Object.assign({}, this.bitstreamsOptions, { currentPage: page })})))
     );
     this.updates$ = this.bitstreamsRD$.pipe(
       toBitstreamsArray(),
       tap((bitstreams: Bitstream[]) => {
-        if (hasNoValue(this.lastInitializedWithSize) || this.currentSize$.value !== this.lastInitializedWithSize) {
+        // Pages in the field-update store are indexed starting at 0 (because they're stored in an array of pages)
-          this.objectUpdatesService.initialize(this.bundle.self, bitstreams, new Date(), true);
+        const updatesPage = this.currentPage$.value - 1;
-          this.lastInitializedWithSize = this.currentSize$.value;
+        if (isEmpty(this.initializedPages)) {
+          // No updates have been initialized yet for this bundle, initialize the first page
+          this.objectUpdatesService.initializeWithCustomOrder(this.bundle.self, bitstreams, new Date(), this.batchSize, updatesPage);
+          this.initializedPages.push(updatesPage);
+        } else if (this.initializedPages.indexOf(this.currentPage$.value) < 0) {
+          // Updates were initialized for this bundle, but not the page we're on. Add the current page to the field-update store for this bundle
+          this.objectUpdatesService.addPageToCustomOrder(this.bundle.self, bitstreams, updatesPage);
+          this.initializedPages.push(updatesPage);
         }
       }),
-      switchMap((bitstreams: Bitstream[]) => this.objectUpdatesService.getFieldUpdatesByCustomOrder(this.bundle.self, bitstreams))
+      switchMap((bitstreams: Bitstream[]) => this.objectUpdatesService.getFieldUpdatesByCustomOrder(this.bundle.self, bitstreams, this.currentPage$.value - 1))
-    );
-    this.isLoadingMore$ = observableCombineLatest(this.currentSize$, this.bitstreamsRD$).pipe(
-      map(([size, bitstreamsRD]: [number, RemoteData<PaginatedList<Bitstream>>]) => size > bitstreamsRD.payload.page.length)
     );
 
     this.viewContainerRef.createEmbeddedView(this.bundleView);
   }
 
+  /**
+   * Update the current page
+   * @param page
+   */
+  switchPage(page: number) {
+    this.currentPage$.next(page);
+  }
+
   /**
    * A bitstream was moved, send updates to the store
    * @param event
@@ -117,18 +123,4 @@ export class ItemEditBitstreamBundleComponent implements OnInit {
   drop(event: CdkDragDrop<any>) {
     this.objectUpdatesService.saveMoveFieldUpdate(this.bundle.self, event.previousIndex, event.currentIndex);
   }
-
-  /**
-   * Load more bitstreams (current size + batchSize)
-   */
-  loadMore() {
-    this.currentSize$.next(this.currentSize$.value + this.batchSize);
-  }
-
-  /**
-   * Load all bitstreams
-   */
-  loadAll() {
-    this.currentSize$.next(9999);
-  }
 }

src/app/core/data/array-move-change-analyzer.service.ts

@@ -5,6 +5,7 @@ import { Injectable } from '@angular/core';
 import { CacheableObject } from '../cache/object-cache.reducer';
 import { NormalizedObject } from '../cache/models/normalized-object.model';
 import { moveItemInArray } from '@angular/cdk/drag-drop';
+import { hasValue } from '../../shared/empty.util';
 
 /**
  * A class to determine move operations between two arrays
@@ -22,6 +23,7 @@ export class ArrayMoveChangeAnalyzer<T> {
     const result = [];
     const moved = [...array1];
     array1.forEach((value: T, index: number) => {
+      if (hasValue(value)) {
         const otherIndex = array2.indexOf(value);
         const movedIndex = moved.indexOf(value);
         if (index !== otherIndex && movedIndex !== otherIndex) {
@@ -32,6 +34,7 @@ export class ArrayMoveChangeAnalyzer<T> {
             path: '/' + otherIndex
           }) as MoveOperation)
         }
+      }
     });
     return result;
   }

src/app/core/data/object-updates/object-updates.actions.ts

@@ -8,6 +8,7 @@ import { INotification } from '../../../shared/notifications/models/notification
  */
 export const ObjectUpdatesActionTypes = {
   INITIALIZE_FIELDS: type('dspace/core/cache/object-updates/INITIALIZE_FIELDS'),
+  ADD_PAGE_TO_CUSTOM_ORDER: type('dspace/core/cache/object-updates/ADD_PAGE_TO_CUSTOM_ORDER'),
   SET_EDITABLE_FIELD: type('dspace/core/cache/object-updates/SET_EDITABLE_FIELD'),
   SET_VALID_FIELD: type('dspace/core/cache/object-updates/SET_VALID_FIELD'),
   ADD_FIELD: type('dspace/core/cache/object-updates/ADD_FIELD'),
@@ -39,7 +40,9 @@ export class InitializeFieldsAction implements Action {
     url: string,
     fields: Identifiable[],
     lastModified: Date,
-    order: string[]
+    order: string[],
+    pageSize: number,
+    page: number
   };
 
   /**
@@ -50,14 +53,48 @@ export class InitializeFieldsAction implements Action {
    * @param fields The identifiable fields of which the updates are kept track of
    * @param lastModified The last modified date of the object that belongs to the page
    * @param order A custom order to keep track of objects moving around
+   * @param pageSize The page size used to fill empty pages for the custom order
+   * @param page The first page to populate in the custom order
    */
   constructor(
     url: string,
     fields: Identifiable[],
     lastModified: Date,
-    order: string[] = []
+    order: string[] = [],
+    pageSize: number = 9999,
+    page: number = 0
   ) {
-    this.payload = { url, fields, lastModified, order };
+    this.payload = { url, fields, lastModified, order, pageSize, page };
+  }
+}
+
+/**
+ * An ngrx action to initialize a new page's fields in the ObjectUpdates state
+ */
+export class AddPageToCustomOrderAction implements Action {
+  type = ObjectUpdatesActionTypes.ADD_PAGE_TO_CUSTOM_ORDER;
+  payload: {
+    url: string,
+    fields: Identifiable[],
+    order: string[],
+    page: number
+  };
+
+  /**
+   * Create a new AddPageToCustomOrderAction
+   *
+   * @param url The unique url of the page for which the fields are being added
+   * @param fields The identifiable fields of which the updates are kept track of
+   * @param order A custom order to keep track of objects moving around
+   * @param page The page to populate in the custom order
+   */
+  constructor(
+    url: string,
+    fields: Identifiable[],
+    order: string[] = [],
+    page: number = 0
+  ) {
+    this.payload = { url, fields, order, page };
   }
 }
 
@@ -254,7 +291,9 @@ export class MoveFieldUpdateAction implements Action {
   payload: {
     url: string,
     from: number,
-    to: number
+    to: number,
+    fromPage: number,
+    toPage: number
   };
 
   /**
@@ -264,13 +303,17 @@ export class MoveFieldUpdateAction implements Action {
    *    the unique url of the page for which a field's change should be removed
    * @param from      The index of the object to move
    * @param to        The index to move the object to
+   * @param fromPage  The page to move the object from
+   * @param toPage    The page to move the object to
    */
   constructor(
     url: string,
     from: number,
-    to: number
+    to: number,
+    fromPage: number,
+    toPage: number
   ) {
-    this.payload = { url, from, to };
+    this.payload = { url, from, to, fromPage, toPage };
   }
 }
 
@@ -286,4 +329,5 @@ export type ObjectUpdatesAction
   | ReinstateObjectUpdatesAction
   | RemoveObjectUpdatesAction
   | RemoveFieldUpdateAction
-  | MoveFieldUpdateAction;
+  | MoveFieldUpdateAction
+  | AddPageToCustomOrderAction;

src/app/core/data/object-updates/object-updates.reducer.ts

@@ -1,5 +1,5 @@
 import {
-  AddFieldUpdateAction,
+  AddFieldUpdateAction, AddPageToCustomOrderAction,
   DiscardObjectUpdatesAction,
   FieldChangeType,
   InitializeFieldsAction, MoveFieldUpdateAction,
@@ -9,8 +9,9 @@ import {
   RemoveFieldUpdateAction,
   RemoveObjectUpdatesAction, SetEditableFieldUpdateAction, SetValidFieldUpdateAction
 } from './object-updates.actions';
-import { hasNoValue, hasValue, isNotEmpty } from '../../../shared/empty.util';
+import { hasNoValue, hasValue, isEmpty, isNotEmpty } from '../../../shared/empty.util';
-import { moveItemInArray } from '@angular/cdk/drag-drop';
+import { moveItemInArray, transferArrayItem } from '@angular/cdk/drag-drop';
+import { from } from 'rxjs/internal/observable/from';
 
 /**
  * Path where discarded objects are saved
@@ -59,11 +60,16 @@ export interface FieldUpdates {
  * A custom order given to the list of objects
  */
 export interface CustomOrder {
-  initialOrder: string[],
+  initialOrderPages: OrderPage[],
-  newOrder: string[],
+  newOrderPages: OrderPage[],
+  pageSize: number;
   changed: boolean
 }
 
+export interface OrderPage {
+  order: string[]
+}
+
 /**
  * The updated state of a single page
  */
@@ -104,6 +110,9 @@ export function objectUpdatesReducer(state = initialState, action: ObjectUpdates
     case ObjectUpdatesActionTypes.INITIALIZE_FIELDS: {
       return initializeFieldsUpdate(state, action as InitializeFieldsAction);
     }
+    case ObjectUpdatesActionTypes.ADD_PAGE_TO_CUSTOM_ORDER: {
+      return addPageToCustomOrder(state, action as AddPageToCustomOrderAction);
+    }
     case ObjectUpdatesActionTypes.ADD_FIELD: {
       return addFieldUpdate(state, action as AddFieldUpdateAction);
     }
@@ -147,18 +156,47 @@ function initializeFieldsUpdate(state: any, action: InitializeFieldsAction) {
   const fields: Identifiable[] = action.payload.fields;
   const lastModifiedServer: Date = action.payload.lastModified;
   const order = action.payload.order;
+  const pageSize = action.payload.pageSize;
+  const page = action.payload.page;
   const fieldStates = createInitialFieldStates(fields);
+  const initialOrderPages = addOrderToPages([], order, pageSize, page);
   const newPageState = Object.assign(
     {},
     state[url],
     { fieldStates: fieldStates },
     { fieldUpdates: {} },
     { lastModified: lastModifiedServer },
-    { customOrder: { initialOrder: order, newOrder: order, changed: false } }
+    { customOrder: {
+      initialOrderPages: initialOrderPages,
+      newOrderPages: initialOrderPages,
+      pageSize: 9999,
+      changed: false }
+    }
   );
   return Object.assign({}, state, { [url]: newPageState });
 }
 
+/**
+ * Add a page of objects to the state of a specific url and update a specific page of the custom order
+ * @param state The current state
+ * @param action The action to perform on the current state
+ */
+function addPageToCustomOrder(state: any, action: AddPageToCustomOrderAction) {
+  const url: string = action.payload.url;
+  const fields: Identifiable[] = action.payload.fields;
+  const order = action.payload.order;
+  const page = action.payload.page;
+  const pageState: ObjectUpdatesEntry = state[url] || {};
+  const newPageState = Object.assign({}, pageState, {
+    fieldStates: Object.assign({}, pageState.fieldStates, fields),
+    customOrder: Object.assign({}, pageState.customOrder, {
+      newOrderPages: addOrderToPages(pageState.customOrder.newOrderPages, order, pageState.customOrder.pageSize, page),
+      initialOrderPages: addOrderToPages(pageState.customOrder.initialOrderPages, order, pageState.customOrder.pageSize, page)
+    })
+  });
+  return Object.assign({}, state, { [url]: newPageState });
+}
+
 /**
  * Add a new update for a specific field to the store
  * @param state The current state
@@ -224,9 +262,9 @@ function discardObjectUpdatesFor(url: string, state: any) {
 
   const newCustomOrder = Object.assign({}, pageState.customOrder);
   if (pageState.customOrder.changed) {
-    const initialOrder = pageState.customOrder.initialOrder;
+    const initialOrder = pageState.customOrder.initialOrderPages;
     if (isNotEmpty(initialOrder)) {
-      newCustomOrder.newOrder = initialOrder;
+      newCustomOrder.newOrderPages = initialOrder;
       newCustomOrder.changed = false;
     }
   }
@@ -389,6 +427,17 @@ function createInitialFieldStates(fields: Identifiable[]) {
   return fieldStates;
 }
 
+/**
+ * Method to add a list of objects to an existing FieldStates object
+ * @param fieldStates                   FieldStates to add states to
+ * @param fields Identifiable objects   The list of objects to add to the FieldStates
+ */
+function addFieldStates(fieldStates: FieldStates, fields: Identifiable[]) {
+  const uuids = fields.map((field: Identifiable) => field.uuid);
+  uuids.forEach((uuid: string) => fieldStates[uuid] = initialFieldState);
+  return fieldStates;
+}
+
 /**
  * Move an object within the custom order of a page state
  * @param state   The current state
@@ -396,23 +445,64 @@ function createInitialFieldStates(fields: Identifiable[]) {
  */
 function moveFieldUpdate(state: any, action: MoveFieldUpdateAction) {
   const url = action.payload.url;
-  const from = action.payload.from;
+  const fromIndex = action.payload.from;
-  const to = action.payload.to;
+  const toIndex = action.payload.to;
+  const fromPage = action.payload.fromPage;
+  const toPage = action.payload.toPage;
 
   const pageState: ObjectUpdatesEntry = state[url];
-  const initialOrder = pageState.customOrder.initialOrder;
+  const initialOrderPages = pageState.customOrder.initialOrderPages;
-  const customOrder = [...pageState.customOrder.newOrder];
+  const customOrderPages = [...pageState.customOrder.newOrderPages];
-  if (isNotEmpty(customOrder) && isNotEmpty(customOrder[from]) && isNotEmpty(customOrder[to])) {
+  if (fromPage === toPage) {
-    moveItemInArray(customOrder, from, to);
+    if (isNotEmpty(customOrderPages[fromPage]) && isNotEmpty(customOrderPages[fromPage].order[fromIndex]) && isNotEmpty(customOrderPages[fromPage].order[toIndex])) {
+      moveItemInArray(customOrderPages[fromPage].order, fromIndex, toIndex);
+    }
+  } else {
+    if (isNotEmpty(customOrderPages[fromPage]) && isNotEmpty(customOrderPages[toPage]) && isNotEmpty(customOrderPages[fromPage].order[fromIndex]) && isNotEmpty(customOrderPages[toPage].order[toIndex])) {
+      transferArrayItem(customOrderPages[fromPage].order, customOrderPages[toPage].order, fromIndex, toIndex);
+    }
   }
 
   let changed = false;
-  initialOrder.forEach((id: string, index: number) => {
+  initialOrderPages.forEach((orderPage: OrderPage, page: number) => {
-    if (id !== customOrder[index]) {
+    if (isNotEmpty(orderPage) && isNotEmpty(orderPage.order) && isNotEmpty(customOrderPages[page]) && isNotEmpty(customOrderPages[page].order)) {
+      orderPage.order.forEach((id: string, index: number) => {
+        if (id !== customOrderPages[page].order[index]) {
           changed = true;
           return;
         }
       });
-
+      if (changed) {
-  return Object.assign({}, state, { [url]: Object.assign({}, pageState, { customOrder: Object.assign({}, pageState.customOrder, { newOrder: customOrder, changed: changed }) }) })
+        return;
+      }
+    }
+  });
+
+  return Object.assign({}, state, { [url]: Object.assign({}, pageState, { customOrder: Object.assign({}, pageState.customOrder, { newOrderPages: customOrderPages, changed: changed }) }) })
+}
+
+/**
+ * Initialize a custom order page by providing the list of all pages, a list of UUIDs, pageSize and the page to populate
+ * @param initialPages  The initial list of OrderPage objects
+ * @param order         The list of UUIDs to create a page for
+ * @param pageSize      The pageSize used to populate empty spacer pages
+ * @param page          The index of the page to add
+ */
+function addOrderToPages(initialPages: OrderPage[], order: string[], pageSize: number, page: number): OrderPage[] {
+  const result = [...initialPages];
+  const orderPage: OrderPage = { order: order };
+  if (page < result.length) {
+    // The page we're trying to add already exists in the list. Overwrite it.
+    result[page] = orderPage;
+  } else if (page === result.length) {
+    // The page we're trying to add is the next page in the list, add it.
+    result.push(orderPage);
+  } else {
+    // The page we're trying to add is at least one page ahead of the list, fill the list with empty pages before adding the page.
+    const emptyOrderPage: OrderPage = { order: [] };
+    emptyOrderPage.order.fill(undefined, 0, pageSize);
+    result.fill(emptyOrderPage, result.length, page - 1);
+    result.push(orderPage);
+  }
+  return result;
 }

src/app/core/data/object-updates/object-updates.service.ts

@@ -8,11 +8,11 @@ import {
   Identifiable,
   OBJECT_UPDATES_TRASH_PATH,
   ObjectUpdatesEntry,
-  ObjectUpdatesState
+  ObjectUpdatesState, OrderPage
 } from './object-updates.reducer';
 import { Observable } from 'rxjs';
 import {
-  AddFieldUpdateAction,
+  AddFieldUpdateAction, AddPageToCustomOrderAction,
   DiscardObjectUpdatesAction,
   FieldChangeType,
   InitializeFieldsAction,
@@ -28,6 +28,7 @@ import { INotification } from '../../../shared/notifications/models/notification
 import { Operation } from 'fast-json-patch';
 import { ArrayMoveChangeAnalyzer } from '../array-move-change-analyzer.service';
 import { MoveOperation } from 'fast-json-patch/lib/core';
+import { flatten } from '@angular/compiler';
 
 function objectUpdatesStateSelector(): MemoizedSelector<CoreState, ObjectUpdatesState> {
   return createSelector(coreSelector, (state: CoreState) => state['cache/object-updates']);
@@ -56,10 +57,25 @@ export class ObjectUpdatesService {
    * @param url The page's URL for which the changes are being mapped
    * @param fields The initial fields for the page's object
    * @param lastModified The date the object was last modified
-   * @param addCustomOrder Add a custom order list to track move changes
    */
-  initialize(url, fields: Identifiable[], lastModified: Date, addCustomOrder?: boolean): void {
+  initialize(url, fields: Identifiable[], lastModified: Date): void {
-    this.store.dispatch(new InitializeFieldsAction(url, fields, lastModified, addCustomOrder ? fields.map((field) => field.uuid) : []));
+    this.store.dispatch(new InitializeFieldsAction(url, fields, lastModified));
+  }
+
+  /**
+   * Method to dispatch an InitializeFieldsAction to the store and keeping track of the order objects are stored
+   * @param url The page's URL for which the changes are being mapped
+   * @param fields The initial fields for the page's object
+   * @param lastModified The date the object was last modified
+   * @param pageSize The page size to use for adding pages to the custom order
+   * @param page The first page to populate the custom order with
+   */
+  initializeWithCustomOrder(url, fields: Identifiable[], lastModified: Date, pageSize = 9999, page = 0): void {
+    this.store.dispatch(new InitializeFieldsAction(url, fields, lastModified, fields.map((field) => field.uuid), pageSize, page));
+  }
+
+  addPageToCustomOrder(url, fields: Identifiable[], page: number): void {
+    this.store.dispatch(new AddPageToCustomOrderAction(url, fields, fields.map((field) => field.uuid), page));
   }
 
   /**
@@ -140,13 +156,14 @@ export class ObjectUpdatesService {
    * sorted by their custom order to create a FieldUpdates object
    * @param url The URL of the page for which the FieldUpdates should be requested
    * @param initialFields The initial values of the fields
+   * @param page The page to retrieve
    */
-  getFieldUpdatesByCustomOrder(url: string, initialFields: Identifiable[]): Observable<FieldUpdates> {
+  getFieldUpdatesByCustomOrder(url: string, initialFields: Identifiable[], page = 0): Observable<FieldUpdates> {
     const objectUpdates = this.getObjectEntry(url);
     return objectUpdates.pipe(map((objectEntry) => {
       const fieldUpdates: FieldUpdates = {};
       if (hasValue(objectEntry)) {
-        for (const uuid of objectEntry.customOrder.newOrder) {
+        for (const uuid of objectEntry.customOrder.newOrderPages[page].order) {
           let fieldUpdate = objectEntry.fieldUpdates[uuid];
           if (isEmpty(fieldUpdate)) {
             const identifiable = initialFields.find((object: Identifiable) => object.uuid === uuid);
@@ -233,9 +250,11 @@ export class ObjectUpdatesService {
    * @param url       The page's URL for which the changes are saved
    * @param from      The index of the object to move
    * @param to        The index to move the object to
+   * @param fromPage  The page to move the object from
+   * @param toPage    The page to move the object to
    */
-  saveMoveFieldUpdate(url: string, from: number, to: number) {
+  saveMoveFieldUpdate(url: string, from: number, to: number, fromPage = 0, toPage = 0) {
-    this.store.dispatch(new MoveFieldUpdateAction(url, from, to));
+    this.store.dispatch(new MoveFieldUpdateAction(url, from, to, fromPage, toPage));
   }
 
   /**
@@ -350,7 +369,10 @@ export class ObjectUpdatesService {
   getMoveOperations(url: string): Observable<MoveOperation[]> {
     return this.getObjectEntry(url).pipe(
       map((objectEntry) => objectEntry.customOrder),
-      map((customOrder) => this.comparator.diff(customOrder.initialOrder, customOrder.newOrder))
+      map((customOrder) => this.comparator.diff(
+        flatten(customOrder.initialOrderPages.map((orderPage: OrderPage) => orderPage.order)),
+        flatten(customOrder.newOrderPages.map((orderPage: OrderPage) => orderPage.order)))
+      )
     );
   }
 

src/app/shared/pagination-drag-and-drop/pagination-drag-and-drop.component.html

@@ -0,0 +1,11 @@
+<ds-pagination *ngIf="paginatedList"
+               [hideGear]="hideGear"
+               [hidePagerWhenSinglePage]="hidePagerWhenSinglePage"
+               [hidePaginationDetail]="hidePaginationDetail"
+               [paginationOptions]="paginationOptions"
+               [pageInfoState]="paginatedList"
+               [collectionSize]="paginatedList?.totalElements"
+               [disableRouteParameterUpdate]="disableRouteParameterUpdate"
+               (pageChange)="switchPage($event)">
+  <ng-content></ng-content>
+</ds-pagination>

src/app/shared/pagination-drag-and-drop/pagination-drag-and-drop.component.ts

@@ -0,0 +1,55 @@
+import { Component, EventEmitter, Input, Output } from '@angular/core';
+import { PaginationComponentOptions } from '../pagination/pagination-component-options.model';
+import { PaginatedList } from '../../core/data/paginated-list';
+
+@Component({
+  selector: 'ds-pagination-drag-and-drop',
+  templateUrl: './pagination-drag-and-drop.component.html',
+})
+export class PaginationDragAndDropComponent {
+  /**
+   * Configuration for the NgbPagination component.
+   */
+  @Input() paginationOptions: PaginationComponentOptions;
+
+  /**
+   * The paginated list being displayed
+   */
+  @Input() paginatedList: PaginatedList<any>;
+
+  /**
+   * Option for hiding the pagination detail
+   */
+  @Input() public hidePaginationDetail = false;
+
+  /**
+   * Option for hiding the gear
+   */
+  @Input() public hideGear = false;
+
+  /**
+   * Option for hiding the pager when there is less than 2 pages
+   */
+  @Input() public hidePagerWhenSinglePage = true;
+
+  /**
+   * Option for disabling updating and reading route parameters on pagination changes
+   * In other words, changing pagination won't add or update the url parameters on the current page, and the url
+   * parameters won't affect the pagination of this component
+   */
+  @Input() public disableRouteParameterUpdate = false;
+
+  /**
+   * An event fired when the page is changed.
+   * Event's payload equals to the newly selected page.
+   */
+  @Output() pageChange: EventEmitter<number> = new EventEmitter<number>();
+
+  /**
+   * Switch to a different page
+   * @param page  Page to switch to
+   */
+  switchPage(page: number) {
+    this.pageChange.emit(page);
+  }
+}

src/app/shared/pagination/pagination.component.ts

@@ -99,6 +99,13 @@ export class PaginationComponent implements OnDestroy, OnInit {
    */
   @Input() public hidePagerWhenSinglePage = true;
 
+  /**
+   * Option for disabling updating and reading route parameters on pagination changes
+   * In other words, changing pagination won't add or update the url parameters on the current page, and the url
+   * parameters won't affect the pagination of this component
+   */
+  @Input() public disableRouteParameterUpdate = false;
+
   /**
    * Current page.
    */
@@ -173,20 +180,35 @@ export class PaginationComponent implements OnDestroy, OnInit {
     this.checkConfig(this.paginationOptions);
     this.initializeConfig();
     // Listen to changes
+    if (!this.disableRouteParameterUpdate) {
       this.subs.push(this.route.queryParams
         .subscribe((queryParams) => {
-        if (this.isEmptyPaginationParams(queryParams)) {
+          this.initializeParams(queryParams);
-          this.initializeConfig(queryParams);
+        }));
+    }
+  }
+
+  /**
+   * Initialize the route and current parameters
+   * This method will fix any invalid or missing parameters
+   * @param params
+   */
+  private initializeParams(params) {
+    if (this.isEmptyPaginationParams(params)) {
+      this.initializeConfig(params);
     } else {
-          this.currentQueryParams = queryParams;
+      this.currentQueryParams = params;
-          const fixedProperties = this.validateParams(queryParams);
+      const fixedProperties = this.validateParams(params);
       if (isNotEmpty(fixedProperties)) {
+        if (!this.disableRouteParameterUpdate) {
           this.fixRoute(fixedProperties);
+        } else {
+          this.initializeParams(fixedProperties);
+        }
       } else {
         this.setFields();
       }
     }
-      }));
   }
 
   private fixRoute(fixedProperties) {
@@ -247,7 +269,7 @@ export class PaginationComponent implements OnDestroy, OnInit {
    *    The page being navigated to.
    */
   public doPageChange(page: number) {
-    this.updateRoute({ pageId: this.id, page: page.toString() });
+    this.updateParams(Object.assign({}, this.currentQueryParams, { pageId: this.id, page: page.toString() }));
   }
 
   /**
@@ -257,7 +279,7 @@ export class PaginationComponent implements OnDestroy, OnInit {
    *    The page size being navigated to.
    */
   public doPageSizeChange(pageSize: number) {
-    this.updateRoute({ pageId: this.id, page: 1, pageSize: pageSize });
+    this.updateParams(Object.assign({}, this.currentQueryParams,{ pageId: this.id, page: 1, pageSize: pageSize }));
   }
 
   /**
@@ -267,7 +289,7 @@ export class PaginationComponent implements OnDestroy, OnInit {
    *    The sort direction being navigated to.
    */
   public doSortDirectionChange(sortDirection: SortDirection) {
-    this.updateRoute({ pageId: this.id, page: 1, sortDirection: sortDirection });
+    this.updateParams(Object.assign({}, this.currentQueryParams,{ pageId: this.id, page: 1, sortDirection: sortDirection }));
   }
 
   /**
@@ -277,7 +299,7 @@ export class PaginationComponent implements OnDestroy, OnInit {
    *    The sort field being navigated to.
    */
   public doSortFieldChange(field: string) {
-    this.updateRoute({ pageId: this.id, page: 1, sortField: field });
+    this.updateParams(Object.assign(this.currentQueryParams,{ pageId: this.id, page: 1, sortField: field }));
   }
 
   /**
@@ -347,6 +369,20 @@ export class PaginationComponent implements OnDestroy, OnInit {
       })
   }
 
+  /**
+   * Update the current query params and optionally update the route
+   * @param params
+   */
+  private updateParams(params: {}) {
+    if (isNotEmpty(difference(params, this.currentQueryParams))) {
+      if (!this.disableRouteParameterUpdate) {
+        this.updateRoute(params);
+      } else {
+        this.initializeParams(params);
+      }
+    }
+  }
+
   /**
    * Method to update the route parameters
    */

src/app/shared/shared.module.ts

@@ -178,6 +178,7 @@ import { ImportableListItemControlComponent } from './object-collection/shared/i
 import { DragDropModule } from '@angular/cdk/drag-drop';
 import { ExistingMetadataListElementComponent } from './form/builder/ds-dynamic-form-ui/existing-metadata-list-element/existing-metadata-list-element.component';
 import { CustomSwitchComponent } from './form/builder/ds-dynamic-form-ui/models/custom-switch/custom-switch.component';
+import { PaginationDragAndDropComponent } from './pagination-drag-and-drop/pagination-drag-and-drop.component';
 
 const MODULES = [
   // Do NOT include UniversalModule, HttpModule, or JsonpModule here
@@ -263,6 +264,7 @@ const COMPONENTS = [
   AbstractListableElementComponent,
   ObjectCollectionComponent,
   PaginationComponent,
+  PaginationDragAndDropComponent,
   SearchFormComponent,
   PageWithSidebarComponent,
   SidebarDropdownComponent,