[Port dspace-8_x] Vocabulary preloadlevel fix

src/app/shared/form/vocabulary-treeview/vocabulary-treeview.component.spec.ts

@@ -21,6 +21,7 @@ import { VocabularyEntry } from '../../../core/submission/vocabularies/models/vo
 import { VocabularyEntryDetail } from '../../../core/submission/vocabularies/models/vocabulary-entry-detail.model';
 import { VocabularyOptions } from '../../../core/submission/vocabularies/models/vocabulary-options.model';
 import { VocabularyService } from '../../../core/submission/vocabularies/vocabulary.service';
+import { createSuccessfulRemoteDataObject$ } from '../../remote-data.utils';
 import { createTestComponent } from '../../testing/utils.test';
 import { FormFieldMetadataValueObject } from '../builder/models/form-field-metadata-value.model';
 import { VocabularyTreeviewComponent } from './vocabulary-treeview.component';
@@ -63,6 +64,7 @@ describe('VocabularyTreeviewComponent test suite', () => {
     searchTopEntries: jasmine.createSpy('searchTopEntries'),
     getEntryDetailChildren: jasmine.createSpy('getEntryDetailChildren'),
     clearSearchTopRequests: jasmine.createSpy('clearSearchTopRequests'),
+    findVocabularyById: createSuccessfulRemoteDataObject$({ preloadLevel: 2 }),
   });
 
   beforeEach(waitForAsync(() => {

src/app/shared/form/vocabulary-treeview/vocabulary-treeview.component.ts

@@ -25,11 +25,20 @@ import {
   Observable,
   Subscription,
 } from 'rxjs';
+import {
+  map,
+  switchMap,
+  tap,
+} from 'rxjs/operators';
 
+import { RemoteData } from '../../../core/data/remote-data';
+import { getFirstCompletedRemoteData } from '../../../core/shared/operators';
 import { PageInfo } from '../../../core/shared/page-info.model';
+import { Vocabulary } from '../../../core/submission/vocabularies/models/vocabulary.model';
 import { VocabularyEntry } from '../../../core/submission/vocabularies/models/vocabulary-entry.model';
 import { VocabularyEntryDetail } from '../../../core/submission/vocabularies/models/vocabulary-entry-detail.model';
 import { VocabularyOptions } from '../../../core/submission/vocabularies/models/vocabulary-options.model';
+import { VocabularyService } from '../../../core/submission/vocabularies/vocabulary.service';
 import { AlertComponent } from '../../alert/alert.component';
 import { AlertType } from '../../alert/alert-type';
 import {
@@ -165,9 +174,11 @@ export class VocabularyTreeviewComponent implements OnDestroy, OnInit, OnChanges
    * Initialize instance variables
    *
    * @param {VocabularyTreeviewService} vocabularyTreeviewService
+   * @param {VocabularyService} vocabularyService
    */
   constructor(
     private vocabularyTreeviewService: VocabularyTreeviewService,
+    protected vocabularyService: VocabularyService,
   ) {
     this.treeFlattener = new VocabularyTreeFlattener(this.transformer, this.getLevel,
       this.isExpandable, this.getChildren);
@@ -209,12 +220,20 @@ export class VocabularyTreeviewComponent implements OnDestroy, OnInit, OnChanges
     );
     this.nodeMap.set(entryId, newNode);
 
-    if ((((level + 1) < this.preloadLevel) && newNode.childrenLoaded)
+    if ((((level + 1) < this.preloadLevel))
       || (newNode.isSearchNode && newNode.childrenLoaded)
       || newNode.isInInitValueHierarchy) {
-      if (!newNode.isSearchNode) {
+
+      if (newNode.item.id === LOAD_MORE || newNode.item.id === LOAD_MORE_ROOT) {
+        // When a 'LOAD_MORE' node is encountered, the parent already has a lot of expanded children
+        // so this is a good point to stop expanding.
+        return newNode;
+      }
+
+      if (!newNode.childrenLoaded) {
         this.loadChildren(newNode);
       }
+
       this.treeControl.expand(newNode);
     }
     return newNode;
@@ -255,15 +274,31 @@ export class VocabularyTreeviewComponent implements OnDestroy, OnInit, OnChanges
    */
   ngOnInit(): void {
     this.subs.push(
-      this.vocabularyTreeviewService.getData().subscribe((data) => {
+      this.vocabularyService.findVocabularyById(this.vocabularyOptions.name).pipe(
+        // Retrieve the configured preloadLevel from REST
+        getFirstCompletedRemoteData(),
+        map((vocabularyRD: RemoteData<Vocabulary>) => {
+          if (vocabularyRD.hasSucceeded &&
+            hasValue(vocabularyRD.payload.preloadLevel) &&
+            vocabularyRD.payload.preloadLevel > 1) {
+            return vocabularyRD.payload.preloadLevel;
+          } else {
+            // Set preload level to 1 in case request fails
+            return 1;
+          }
+        }),
+        tap((preloadLevel: number) => this.preloadLevel = preloadLevel),
+        tap(() => {
+          const entryId: string = (this.selectedItems?.length > 0) ? this.getEntryId(this.selectedItems[0]) : null;
+          this.vocabularyTreeviewService.initialize(this.vocabularyOptions, new PageInfo(), this.getSelectedEntryIds(), entryId);
+        }),
+        switchMap(() => this.vocabularyTreeviewService.getData()),
+      ).subscribe((data) => {
         this.dataSource.data = data;
       }),
     );
 
     this.loading = this.vocabularyTreeviewService.isLoading();
-
-    const entryId: string = (this.selectedItems?.length > 0) ? this.getEntryId(this.selectedItems[0]) : null;
-    this.vocabularyTreeviewService.initialize(this.vocabularyOptions, new PageInfo(), this.getSelectedEntryIds(), entryId);
   }
 
   /**