Merge pull request #347 from atmire/DS-4107_Metadata_as_map

DS-4107 Metadata as map updates for Angular
2025-10-15 05:53:03 +00:00 · 2019-02-21 14:22:37 -06:00
parent 8bf9b509ff c2c59cd85a
commit 562160bb8a
61 changed files with 1222 additions and 826 deletions
--- a/src/app/+community-page/sub-community-list/community-page-sub-community-list.component.spec.ts
+++ b/src/app/+community-page/sub-community-list/community-page-sub-community-list.component.spec.ts
@@ -18,42 +18,38 @@ describe('SubCommunityList Component', () => {

  const subcommunities = [Object.assign(new Community(), {
    id: '123456789-1',
-    metadata: [
-      {
-        key: 'dc.title',
-        language: 'en_US',
-        value: 'SubCommunity 1'
-      }]
+    metadata: {
+      'dc.title': [
+        { language: 'en_US', value: 'SubCommunity 1' }
+      ]
+    }
  }),
    Object.assign(new Community(), {
      id: '123456789-2',
-      metadata: [
-        {
-          key: 'dc.title',
-          language: 'en_US',
-          value: 'SubCommunity 2'
-        }]
+      metadata: {
+        'dc.title': [
+          { language: 'en_US', value: 'SubCommunity 2' }
+        ]
+      }
    })
  ];

  const emptySubCommunitiesCommunity = Object.assign(new Community(), {
-    metadata: [
-      {
-        key: 'dc.title',
-        language: 'en_US',
-        value: 'Test title'
-      }],
+    metadata: {
+      'dc.title': [
+        { language: 'en_US', value: 'Test title' }
+      ]
+    },
    subcommunities: observableOf(new RemoteData(true, true, true,
      undefined, new PaginatedList(new PageInfo(), [])))
  });

  const mockCommunity = Object.assign(new Community(), {
-      metadata: [
-        {
-          key: 'dc.title',
-          language: 'en_US',
-          value: 'Test title'
-        }],
+      metadata: {
+        'dc.title': [
+          { language: 'en_US', value: 'Test title' }
+        ]
+      },
      subcommunities: observableOf(new RemoteData(true, true, true,
        undefined, new PaginatedList(new PageInfo(), subcommunities)))
    })
--- a/src/app/+item-page/edit-item-page/modify-item-overview/modify-item-overview.component.html
+++ b/src/app/+item-page/edit-item-page/modify-item-overview/modify-item-overview.component.html
@@ -7,10 +7,12 @@
  </tr>
  </thead>
  <tbody>
-  <tr *ngFor="let metadatum of metadata" class="metadata-row">
-    <td>{{metadatum.key}}</td>
-    <td>{{metadatum.value}}</td>
-    <td>{{metadatum.language}}</td>
+  <ng-container *ngFor="let mdEntry of metadata | keyvalue">
+    <tr *ngFor="let mdValue of mdEntry.value" class="metadata-row">
+      <td>{{mdEntry.key}}</td>
+      <td>{{mdValue.value}}</td>
+      <td>{{mdValue.language}}</td>
    </tr>
+  </ng-container>
  </tbody>
 </table>
--- a/src/app/+item-page/edit-item-page/modify-item-overview/modify-item-overview.component.spec.ts
+++ b/src/app/+item-page/edit-item-page/modify-item-overview/modify-item-overview.component.spec.ts
@@ -11,10 +11,14 @@ const mockItem = Object.assign(new Item(), {
  id: 'fake-id',
  handle: 'fake/handle',
  lastModified: '2018',
-  metadata: [
-    {key: 'dc.title', value: 'Mock item title', language: 'en'},
-    {key: 'dc.contributor.author', value: 'Mayer, Ed', language: ''}
+  metadata: {
+    'dc.title': [
+      { value: 'Mock item title', language: 'en' }
+    ],
+    'dc.contributor.author': [
+      { value: 'Mayer, Ed', language: '' }
    ]
+  }
 });

 describe('ModifyItemOverviewComponent', () => {
@@ -37,19 +41,19 @@ describe('ModifyItemOverviewComponent', () => {
    const metadataRows = fixture.debugElement.queryAll(By.css('tr.metadata-row'));
    expect(metadataRows.length).toEqual(2);

-    const titleRow = metadataRows[0].queryAll(By.css('td'));
-    expect(titleRow.length).toEqual(3);
-
-    expect(titleRow[0].nativeElement.innerHTML).toContain('dc.title');
-    expect(titleRow[1].nativeElement.innerHTML).toContain('Mock item title');
-    expect(titleRow[2].nativeElement.innerHTML).toContain('en');
-
-    const authorRow = metadataRows[1].queryAll(By.css('td'));
+    const authorRow = metadataRows[0].queryAll(By.css('td'));
    expect(authorRow.length).toEqual(3);

    expect(authorRow[0].nativeElement.innerHTML).toContain('dc.contributor.author');
    expect(authorRow[1].nativeElement.innerHTML).toContain('Mayer, Ed');
    expect(authorRow[2].nativeElement.innerHTML).toEqual('');

+    const titleRow = metadataRows[1].queryAll(By.css('td'));
+    expect(titleRow.length).toEqual(3);
+
+    expect(titleRow[0].nativeElement.innerHTML).toContain('dc.title');
+    expect(titleRow[1].nativeElement.innerHTML).toContain('Mock item title');
+    expect(titleRow[2].nativeElement.innerHTML).toContain('en');
+
  });
 });
--- a/src/app/+item-page/edit-item-page/modify-item-overview/modify-item-overview.component.ts
+++ b/src/app/+item-page/edit-item-page/modify-item-overview/modify-item-overview.component.ts
@@ -1,6 +1,6 @@
 import {Component, Input, OnInit} from '@angular/core';
 import {Item} from '../../../core/shared/item.model';
-import {Metadatum} from '../../../core/shared/metadatum.model';
+import {MetadataMap} from '../../../core/shared/metadata.interfaces';

@Component({
  selector: 'ds-modify-item-overview',
@@ -12,7 +12,7 @@ import {Metadatum} from '../../../core/shared/metadatum.model';
 export class ModifyItemOverviewComponent implements OnInit {

  @Input() item: Item;
-  metadata: Metadatum[];
+  metadata: MetadataMap;

  ngOnInit(): void {
    this.metadata = this.item.metadata;
--- a/src/app/+item-page/field-components/collections/collections.component.spec.ts
+++ b/src/app/+item-page/field-components/collections/collections.component.spec.ts
@@ -14,12 +14,14 @@ let collectionsComponent: CollectionsComponent;
 let fixture: ComponentFixture<CollectionsComponent>;

 const mockCollection1: Collection = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    }]
+      }
+    ]
+  }
 });

 const succeededMockItem: Item = Object.assign(new Item(), {owningCollection: observableOf(new RemoteData(false, false, true, null, mockCollection1))});
--- a/src/app/+item-page/field-components/metadata-uri-values/metadata-uri-values.component.html
+++ b/src/app/+item-page/field-components/metadata-uri-values/metadata-uri-values.component.html
@@ -1,5 +1,5 @@
 <ds-metadata-field-wrapper [label]="label | translate">
-    <a *ngFor="let metadatum of values; let last=last;" [href]="metadatum.value">
-       {{ linktext || metadatum.value }}<span *ngIf="!last" [innerHTML]="separator"></span>
+    <a *ngFor="let mdValue of mdValues; let last=last;" [href]="mdValue.value">
+       {{ linktext || mdValue.value }}<span *ngIf="!last" [innerHTML]="separator"></span>
    </a>
 </ds-metadata-field-wrapper>
--- a/src/app/+item-page/field-components/metadata-uri-values/metadata-uri-values.component.ts
+++ b/src/app/+item-page/field-components/metadata-uri-values/metadata-uri-values.component.ts
@@ -1,6 +1,7 @@
 import { Component, Input } from '@angular/core';

 import { MetadataValuesComponent } from '../metadata-values/metadata-values.component';
+import { MetadataValue } from '../../../core/shared/metadata.interfaces';

 /**
 * This component renders the configured 'values' into the ds-metadata-field-wrapper component as a link.
@@ -18,7 +19,7 @@ export class MetadataUriValuesComponent extends MetadataValuesComponent {

  @Input() linktext: any;

-  @Input() values: any;
+  @Input() mdValues: MetadataValue[];

  @Input() separator: string;

--- a/src/app/+item-page/field-components/metadata-values/metadata-values.component.html
+++ b/src/app/+item-page/field-components/metadata-values/metadata-values.component.html
@@ -1,5 +1,5 @@
 <ds-metadata-field-wrapper [label]="label | translate">
-    <span *ngFor="let metadatum of values; let last=last;">
-        {{metadatum.value}}<span *ngIf="!last" [innerHTML]="separator"></span>
+    <span *ngFor="let mdValue of mdValues; let last=last;">
+        {{mdValue.value}}<span *ngIf="!last" [innerHTML]="separator"></span>
    </span>
 </ds-metadata-field-wrapper>
--- a/src/app/+item-page/field-components/metadata-values/metadata-values.component.ts
+++ b/src/app/+item-page/field-components/metadata-values/metadata-values.component.ts
@@ -1,5 +1,5 @@
 import { Component, Input } from '@angular/core';
-import { Metadatum } from '../../../core/shared/metadatum.model';
+import { MetadataValue } from '../../../core/shared/metadata.interfaces';

 /**
 * This component renders the configured 'values' into the ds-metadata-field-wrapper component.
@@ -12,7 +12,7 @@ import { Metadatum } from '../../../core/shared/metadatum.model';
 })
 export class MetadataValuesComponent {

-  @Input() values: Metadatum[];
+  @Input() mdValues: MetadataValue[];

  @Input() separator: string;

--- a/src/app/+item-page/full/field-components/file-section/full-file-section.component.html
+++ b/src/app/+item-page/full/field-components/file-section/full-file-section.component.html
@@ -17,7 +17,7 @@


                <dt class="col-md-4">{{"item.page.filesection.description" | translate}}</dt>
-                <dd class="col-md-8">{{file.findMetadata("dc.description")}}</dd>
+                <dd class="col-md-8">{{file.firstMetadataValue("dc.description")}}</dd>
            </dl>
        </div>
        <div class="col-2">
--- a/src/app/+item-page/full/full-item-page.component.html
+++ b/src/app/+item-page/full/full-item-page.component.html
@@ -9,11 +9,13 @@
      </div>
      <table class="table table-responsive table-striped">
        <tbody>
-        <tr *ngFor="let metadatum of (metadata$ | async)">
-          <td>{{metadatum.key}}</td>
-          <td>{{metadatum.value}}</td>
-          <td>{{metadatum.language}}</td>
+          <ng-container *ngFor="let mdEntry of (metadata$ | async) | keyvalue">
+            <tr *ngFor="let mdValue of mdEntry.value">
+              <td>{{mdEntry.key}}</td>
+              <td>{{mdValue.value}}</td>
+              <td>{{mdValue.language}}</td>
            </tr>
+          </ng-container>
        </tbody>
      </table>
      <ds-item-page-full-file-section [item]="item"></ds-item-page-full-file-section>
--- a/src/app/+item-page/full/full-item-page.component.ts
+++ b/src/app/+item-page/full/full-item-page.component.ts
@@ -6,7 +6,7 @@ import { ActivatedRoute } from '@angular/router';
 import { Observable } from 'rxjs';

 import { ItemPageComponent } from '../simple/item-page.component';
-import { Metadatum } from '../../core/shared/metadatum.model';
+import { MetadataMap } from '../../core/shared/metadata.interfaces';
 import { ItemDataService } from '../../core/data/item-data.service';

 import { RemoteData } from '../../core/data/remote-data';
@@ -34,7 +34,7 @@ export class FullItemPageComponent extends ItemPageComponent implements OnInit {

  itemRD$: Observable<RemoteData<Item>>;

-  metadata$: Observable<Metadatum[]>;
+  metadata$: Observable<MetadataMap>;

  constructor(route: ActivatedRoute, items: ItemDataService, metadataService: MetadataService) {
    super(route, items, metadataService);
--- a/src/app/+item-page/simple/field-components/specific-field/item-page-specific-field.component.html
+++ b/src/app/+item-page/simple/field-components/specific-field/item-page-specific-field.component.html
@@ -1,3 +1,3 @@
 <div class="item-page-specific-field">
-  <ds-metadata-values [values]="item?.filterMetadata(fields)" [separator]="separator" [label]="label"></ds-metadata-values>
+  <ds-metadata-values [mdValues]="item?.allMetadata(fields)" [separator]="separator" [label]="label"></ds-metadata-values>
 </div>
--- a/src/app/+item-page/simple/field-components/specific-field/title/item-page-title-field.component.html
+++ b/src/app/+item-page/simple/field-components/specific-field/title/item-page-title-field.component.html
@@ -1,3 +1,3 @@
 <h2 class="item-page-title-field">
-  <ds-metadata-values [values]="item?.filterMetadata(fields)"></ds-metadata-values>
+  <ds-metadata-values [mdValues]="item?.allMetadata(fields)"></ds-metadata-values>
 </h2>
--- a/src/app/+item-page/simple/field-components/specific-field/uri/item-page-uri-field.component.html
+++ b/src/app/+item-page/simple/field-components/specific-field/uri/item-page-uri-field.component.html
@@ -1,3 +1,3 @@
 <div class="item-page-specific-field">
-  <ds-metadata-uri-values [values]="item?.filterMetadata(fields)" [separator]="separator" [label]="label"></ds-metadata-uri-values>
+  <ds-metadata-uri-values [mdValues]="item?.allMetadata(fields)" [separator]="separator" [label]="label"></ds-metadata-uri-values>
 </div>
--- a/src/app/+search-page/normalized-search-result.model.ts
+++ b/src/app/+search-page/normalized-search-result.model.ts
@@ -1,5 +1,5 @@
 import { autoserialize } from 'cerialize';
-import { Metadatum } from '../core/shared/metadatum.model';
+import { MetadataMap } from '../core/shared/metadata.interfaces';
 import { ListableObject } from '../shared/object-collection/shared/listable-object.model';

 /**
@@ -16,6 +16,6 @@ export class NormalizedSearchResult implements ListableObject {
   * The metadata that was used to find this item, hithighlighted
   */
  @autoserialize
-  hitHighlights: Metadatum[];
+  hitHighlights: MetadataMap;

 }
--- a/src/app/+search-page/search-result.model.ts
+++ b/src/app/+search-page/search-result.model.ts
@@ -1,5 +1,5 @@
 import { DSpaceObject } from '../core/shared/dspace-object.model';
-import { Metadatum } from '../core/shared/metadatum.model';
+import { MetadataMap } from '../core/shared/metadata.interfaces';
 import { ListableObject } from '../shared/object-collection/shared/listable-object.model';

 /**
@@ -14,6 +14,6 @@ export class SearchResult<T extends DSpaceObject> implements ListableObject {
  /**
   * The metadata that was used to find this item, hithighlighted
   */
-  hitHighlights: Metadatum[];
+  hitHighlights: MetadataMap;

 }
--- a/src/app/+search-page/search-results/search-results.component.spec.ts
+++ b/src/app/+search-page/search-results/search-results.component.spec.ts
@@ -111,33 +111,38 @@ export const objects = [
    id: '7669c72a-3f2a-451f-a3b9-9210e7a4c02f',
    uuid: '7669c72a-3f2a-451f-a3b9-9210e7a4c02f',
    type: ResourceType.Community,
-    metadata: [
+    metadata: {
+      'dc.description': [
        {
-        key: 'dc.description',
          language: null,
          value: ''
-      },
+        }
+      ],
+      'dc.description.abstract': [
        {
-        key: 'dc.description.abstract',
          language: null,
          value: 'This is a test community to hold content for the OR2017 demostration'
-      },
+        }
+      ],
+      'dc.description.tableofcontents': [
        {
-        key: 'dc.description.tableofcontents',
          language: null,
          value: ''
-      },
+        }
+      ],
+      'dc.rights': [
        {
-        key: 'dc.rights',
          language: null,
          value: ''
-      },
+        }
+      ],
+      'dc.title': [
        {
-        key: 'dc.title',
          language: null,
          value: 'OR2017 - Demonstration'
        }
      ]
+    }
  }),
  Object.assign(new Community(),
    {
@@ -160,33 +165,38 @@ export const objects = [
      id: '9076bd16-e69a-48d6-9e41-0238cb40d863',
      uuid: '9076bd16-e69a-48d6-9e41-0238cb40d863',
      type: ResourceType.Community,
-      metadata: [
+      metadata: {
+        'dc.description': [
          {
-          key: 'dc.description',
            language: null,
            value: '<p>This is the introductory text for the <em>Sample Community</em> on the DSpace Demonstration Site. It is editable by System or Community Administrators (of this Community).</p>\r\n<p><strong>DSpace Communities may contain one or more Sub-Communities or Collections (of Items).</strong></p>\r\n<p>This particular Community has its own logo (the <a href=\'http://www.duraspace.org/\'>DuraSpace</a> logo).</p>'
-        },
+          }
+        ],
+        'dc.description.abstract': [
          {
-          key: 'dc.description.abstract',
            language: null,
            value: 'This is a sample top-level community'
-        },
+          }
+        ],
+        'dc.description.tableofcontents': [
          {
-          key: 'dc.description.tableofcontents',
            language: null,
            value: '<p>This is the <em>news section</em> for this <em>Sample Community</em>. System or Community Administrators (of this Community) can edit this News field.</p>'
-        },
+          }
+        ],
+        'dc.rights': [
          {
-          key: 'dc.rights',
            language: null,
            value: '<p><em>If this Community had special copyright text to display, it would be displayed here.</em></p>'
-        },
+          }
+        ],
+        'dc.title': [
          {
-          key: 'dc.title',
            language: null,
            value: 'Sample Community'
          }
        ]
      }
+    }
  )
 ];
--- a/src/app/core/auth/auth-response-parsing.service.spec.ts
+++ b/src/app/core/auth/auth-response-parsing.service.spec.ts
@@ -60,23 +60,26 @@ describe('AuthResponseParsingService', () => {
            handle: null,
            id: '4dc70ab5-cd73-492f-b007-3179d2d9296b',
            lastActive: '2018-05-14T17:03:31.277+0000',
-            metadata: [
+            metadata: {
+              'eperson.firstname': [
                {
-                key: 'eperson.firstname',
                  language: null,
                  value: 'User'
-              },
+                }
+              ],
+              'eperson.lastname': [
                {
-                key: 'eperson.lastname',
                  language: null,
                  value: 'Test'
-              },
+                }
+              ],
+              'eperson.language': [
                {
-                key: 'eperson.language',
                  language: null,
                  value: 'en'
                }
-            ],
+              ]
+            },
            name: 'User Test',
            netid: 'myself@testshib.org',
            requireCertificate: false,
--- a/src/app/core/browse/browse.service.spec.ts
+++ b/src/app/core/browse/browse.service.spec.ts
@@ -220,44 +220,44 @@ describe('BrowseService', () => {
            }}));
      });

-      it('should return the URL for the given metadatumKey and linkPath', () => {
-        const metadatumKey = 'dc.date.issued';
+      it('should return the URL for the given metadataKey and linkPath', () => {
+        const metadataKey = 'dc.date.issued';
        const linkPath = 'items';
        const expectedURL = browseDefinitions[0]._links[linkPath];

-        const result = service.getBrowseURLFor(metadatumKey, linkPath);
+        const result = service.getBrowseURLFor(metadataKey, linkPath);
        const expected = cold('c-d-', { c: undefined, d: expectedURL });

        expect(result).toBeObservable(expected);
      });

-      it('should work when the definition uses a wildcard in the metadatumKey', () => {
-        const metadatumKey = 'dc.contributor.author';  // should match dc.contributor.* in the definition
+      it('should work when the definition uses a wildcard in the metadataKey', () => {
+        const metadataKey = 'dc.contributor.author';  // should match dc.contributor.* in the definition
        const linkPath = 'items';
        const expectedURL = browseDefinitions[1]._links[linkPath];

-        const result = service.getBrowseURLFor(metadatumKey, linkPath);
+        const result = service.getBrowseURLFor(metadataKey, linkPath);
        const expected = cold('c-d-', { c: undefined, d: expectedURL });

        expect(result).toBeObservable(expected);
      });

      it('should throw an error when the key doesn\'t match', () => {
-        const metadatumKey = 'dc.title'; // isn't in the definitions
+        const metadataKey = 'dc.title'; // isn't in the definitions
        const linkPath = 'items';

-        const result = service.getBrowseURLFor(metadatumKey, linkPath);
-        const expected = cold('c-#-', { c: undefined }, new Error(`A browse endpoint for ${linkPath} on ${metadatumKey} isn't configured`));
+        const result = service.getBrowseURLFor(metadataKey, linkPath);
+        const expected = cold('c-#-', { c: undefined }, new Error(`A browse endpoint for ${linkPath} on ${metadataKey} isn't configured`));

        expect(result).toBeObservable(expected);
      });

      it('should throw an error when the link doesn\'t match', () => {
-        const metadatumKey = 'dc.date.issued';
+        const metadataKey = 'dc.date.issued';
        const linkPath = 'collections'; // isn't in the definitions

-        const result = service.getBrowseURLFor(metadatumKey, linkPath);
-        const expected = cold('c-#-', { c: undefined }, new Error(`A browse endpoint for ${linkPath} on ${metadatumKey} isn't configured`));
+        const result = service.getBrowseURLFor(metadataKey, linkPath);
+        const expected = cold('c-#-', { c: undefined }, new Error(`A browse endpoint for ${linkPath} on ${metadataKey} isn't configured`));

        expect(result).toBeObservable(expected);
      });
@@ -272,10 +272,10 @@ describe('BrowseService', () => {
        spyOn(service, 'getBrowseDefinitions').and
          .returnValue(hot('----'));

-        const metadatumKey = 'dc.date.issued';
+        const metadataKey = 'dc.date.issued';
        const linkPath = 'items';

-        const result = service.getBrowseURLFor(metadatumKey, linkPath);
+        const result = service.getBrowseURLFor(metadataKey, linkPath);
        const expected = cold('b---', { b: undefined });
        expect(result).toBeObservable(expected);
      });
--- a/src/app/core/browse/browse.service.ts
+++ b/src/app/core/browse/browse.service.ts
@@ -35,12 +35,15 @@ import { Item } from '../shared/item.model';
 import { DSpaceObject } from '../shared/dspace-object.model';
 import { BrowseEntrySearchOptions } from './browse-entry-search-options.model';

+/**
+ * Service that performs all actions that have to do with browse.
+ */
@Injectable()
 export class BrowseService {
  protected linkPath = 'browses';

-  private static toSearchKeyArray(metadatumKey: string): string[] {
-    const keyParts = metadatumKey.split('.');
+  private static toSearchKeyArray(metadataKey: string): string[] {
+    const keyParts = metadataKey.split('.');
    const searchFor = [];
    searchFor.push('*');
    for (let i = 0; i < keyParts.length - 1; i++) {
@@ -48,7 +51,7 @@ export class BrowseService {
      const nextPart = [...prevParts, '*'].join('.');
      searchFor.push(nextPart);
    }
-    searchFor.push(metadatumKey);
+    searchFor.push(metadataKey);
    return searchFor;
  }

@@ -180,8 +183,8 @@ export class BrowseService {
    return this.rdb.toRemoteDataObservable(requestEntry$, payload$);
  }

-  getBrowseURLFor(metadatumKey: string, linkPath: string): Observable<string> {
-    const searchKeyArray = BrowseService.toSearchKeyArray(metadatumKey);
+  getBrowseURLFor(metadataKey: string, linkPath: string): Observable<string> {
+    const searchKeyArray = BrowseService.toSearchKeyArray(metadataKey);
    return this.getBrowseDefinitions().pipe(
      getRemoteDataPayload(),
      map((browseDefinitions: BrowseDefinition[]) => browseDefinitions
@@ -192,7 +195,7 @@ export class BrowseService {
      ),
      map((def: BrowseDefinition) => {
        if (isEmpty(def) || isEmpty(def._links) || isEmpty(def._links[linkPath])) {
-          throw new Error(`A browse endpoint for ${linkPath} on ${metadatumKey} isn't configured`);
+          throw new Error(`A browse endpoint for ${linkPath} on ${metadataKey} isn't configured`);
        } else {
          return def._links[linkPath];
        }
--- a/src/app/core/cache/builders/remote-data-build.service.spec.ts
+++ b/src/app/core/cache/builders/remote-data-build.service.spec.ts
@@ -8,20 +8,24 @@ import { of as observableOf } from 'rxjs';
 const pageInfo = new PageInfo();
 const array = [
  Object.assign(new Item(), {
-    metadata: [
+    metadata: {
+      'dc.title': [
        {
-        key: 'dc.title',
          language: 'en_US',
          value: 'Item nr 1'
-      }]
+        }
+      ]
+    }
  }),
  Object.assign(new Item(), {
-    metadata: [
+    metadata: {
+      'dc.title': [
        {
-        key: 'dc.title',
          language: 'en_US',
          value: 'Item nr 2'
-      }]
+        }
+      ]
+    }
  })
 ];
 const paginatedList = new PaginatedList(pageInfo, array);
--- a/src/app/core/cache/models/normalized-dspace-object.model.ts
+++ b/src/app/core/cache/models/normalized-dspace-object.model.ts
@@ -1,7 +1,6 @@
 import { autoserialize, autoserializeAs, deserialize, serialize } from 'cerialize';
 import { DSpaceObject } from '../../shared/dspace-object.model';
-
-import { Metadatum } from '../../shared/metadatum.model';
+import { MetadataMap } from '../../shared/metadata.interfaces';
 import { ResourceType } from '../../shared/resource-type';
 import { mapsTo } from '../builders/build-decorators';
 import { NormalizedObject } from './normalized-object.model';
@@ -46,10 +45,10 @@ export class NormalizedDSpaceObject extends NormalizedObject {
  type: ResourceType;

  /**
-   * An array containing all metadata of this DSpaceObject
+   * All metadata of this DSpaceObject
   */
-  @autoserializeAs(Metadatum)
-  metadata: Metadatum[];
+  @autoserialize
+  metadata: MetadataMap;

  /**
   * An array of DSpaceObjects that are direct parents of this DSpaceObject
--- a/src/app/core/data/browse-items-response-parsing-service.spec.ts
+++ b/src/app/core/data/browse-items-response-parsing-service.spec.ts
@@ -24,13 +24,14 @@ describe('BrowseItemsResponseParsingService', () => {
              uuid: 'd7b6bc6f-ff6c-444a-a0d3-0cd9b68043e7',
              name: 'Development of Local Supply Chain : A Critical Link for Concentrated Solar Power in India',
              handle: '10986/17472',
-              metadata: [
+              metadata: {
+                'dc.creator': [
                  {
-                  key: 'dc.creator',
                    value: 'World Bank',
                    language: null
                  }
-              ],
+                ]
+              },
              inArchive: true,
              discoverable: true,
              withdrawn: false,
@@ -56,13 +57,14 @@ describe('BrowseItemsResponseParsingService', () => {
              uuid: '27c6f976-257c-4ad0-a0ef-c5e34ffe4d5b',
              name: 'Development of Local Supply Chain : The Missing Link for Concentrated Solar Power Projects in India',
              handle: '10986/17475',
-              metadata: [
+              metadata: {
+                'dc.creator': [
                  {
-                  key: 'dc.creator',
                    value: 'World Bank',
                    language: null
                  }
-              ],
+                ]
+              },
              inArchive: true,
              discoverable: true,
              withdrawn: false,
@@ -115,13 +117,14 @@ describe('BrowseItemsResponseParsingService', () => {
        uuid: 'd7b6bc6f-ff6c-444a-a0d3-0cd9b68043e7',
        name: 'Development of Local Supply Chain : A Critical Link for Concentrated Solar Power in India',
        handle: '10986/17472',
-        metadata: [
+        metadata: {
+          'dc.creator': [
            {
-            key: 'dc.creator',
              value: 'World Bank',
              language: null
            }
-        ],
+          ]
+        },
        inArchive: true,
        discoverable: true,
        withdrawn: false,
--- a/src/app/core/data/search-response-parsing.service.ts
+++ b/src/app/core/data/search-response-parsing.service.ts
@@ -7,7 +7,7 @@ import { DSpaceRESTV2Response } from '../dspace-rest-v2/dspace-rest-v2-response.
 import { DSpaceRESTv2Serializer } from '../dspace-rest-v2/dspace-rest-v2.serializer';
 import { hasValue } from '../../shared/empty.util';
 import { SearchQueryResponse } from '../../+search-page/search-service/search-query-response.model';
-import { Metadatum } from '../shared/metadatum.model';
+import { MetadataMap, MetadataValue } from '../shared/metadata.interfaces';

@Injectable()
 export class SearchResponseParsingService implements ResponseParsingService {
@@ -16,17 +16,17 @@ export class SearchResponseParsingService implements ResponseParsingService {

  parse(request: RestRequest, data: DSpaceRESTV2Response): RestResponse {
    const payload = data.payload._embedded.searchResult;
-    const hitHighlights = payload._embedded.objects
+    const hitHighlights: MetadataMap[] = payload._embedded.objects
      .map((object) => object.hitHighlights)
      .map((hhObject) => {
+        const mdMap: MetadataMap = {};
        if (hhObject) {
-          return Object.keys(hhObject).map((key) => Object.assign(new Metadatum(), {
-            key: key,
-            value: hhObject[key].join('...')
-          }))
-        } else {
-          return [];
+          for (const key of Object.keys(hhObject)) {
+            const value: MetadataValue = { value: hhObject[key].join('...'), language: null };
+            mdMap[key] = [ value ];
          }
+        }
+        return mdMap;
      });

    const dsoSelfLinks = payload._embedded.objects
--- a/src/app/core/dspace-rest-v2/dspace-rest-v2.service.ts
+++ b/src/app/core/dspace-rest-v2/dspace-rest-v2.service.ts
@@ -91,9 +91,9 @@ export class DSpaceRESTv2Service {
    const form: FormData = new FormData();
    form.append('name', dso.name);
    if (dso.metadata) {
-      for (const i of Object.keys(dso.metadata)) {
-        if (isNotEmpty(dso.metadata[i].value)) {
-          form.append(dso.metadata[i].key, dso.metadata[i].value);
+      for (const key of Object.keys(dso.metadata)) {
+        for (const value of dso.allMetadataValues(key)) {
+          form.append(key, value);
        }
      }
    }
--- a/src/app/core/metadata/metadata.service.spec.ts
+++ b/src/app/core/metadata/metadata.service.spec.ts
@@ -37,6 +37,7 @@ import { HttpClient } from '@angular/common/http';
 import { EmptyError } from 'rxjs/internal-compatibility';
 import { NormalizedObjectBuildService } from '../cache/builders/normalized-object-build.service';
 import { DSOChangeAnalyzer } from '../data/dso-change-analyzer.service';
+import { MetadataValue } from '../shared/metadata.interfaces';

 /* tslint:disable:max-classes-per-file */
@Component({
@@ -152,7 +153,7 @@ describe('MetadataService', () => {
    expect(title.getTitle()).toEqual('Test PowerPoint Document');
    expect(tagStore.get('citation_title')[0].content).toEqual('Test PowerPoint Document');
    expect(tagStore.get('citation_author')[0].content).toEqual('Doe, Jane');
-    expect(tagStore.get('citation_date')[0].content).toEqual('1650-06-26T19:58:25Z');
+    expect(tagStore.get('citation_date')[0].content).toEqual('1650-06-26');
    expect(tagStore.get('citation_issn')[0].content).toEqual('123456789');
    expect(tagStore.get('citation_language')[0].content).toEqual('en');
    expect(tagStore.get('citation_keywords')[0].content).toEqual('keyword1; keyword2; keyword3');
@@ -216,22 +217,18 @@ describe('MetadataService', () => {

  const mockType = (mockItem: Item, type: string): Item => {
    const typedMockItem = Object.assign(new Item(), mockItem) as Item;
-    for (const metadatum of typedMockItem.metadata) {
-      if (metadatum.key === 'dc.type') {
-        metadatum.value = type;
-        break;
-      }
-    }
+    typedMockItem.metadata['dc.type'] = [ { value: type } ] as MetadataValue[];
    return typedMockItem;
  }

  const mockPublisher = (mockItem: Item): Item => {
    const publishedMockItem = Object.assign(new Item(), mockItem) as Item;
-    publishedMockItem.metadata.push({
-      key: 'dc.publisher',
+    publishedMockItem.metadata['dc.publisher'] = [
+      {
        language: 'en_US',
        value: 'Mock Publisher'
-    });
+      }
+    ] as MetadataValue[];
    return publishedMockItem;
  }

--- a/src/app/core/metadata/metadata.service.ts
+++ b/src/app/core/metadata/metadata.service.ts
@@ -294,6 +294,10 @@ export class MetadataService {
    }
  }

+  private hasType(value: string): boolean {
+    return this.currentObject.value.hasMetadata('dc.type', { value: value, ignoreCase: true });
+  }
+
  /**
   * Returns true if this._item is a dissertation
   *
@@ -301,14 +305,7 @@ export class MetadataService {
   *      true if this._item has a dc.type equal to 'Thesis'
   */
  private isDissertation(): boolean {
-    let isDissertation = false;
-    for (const metadatum of this.currentObject.value.metadata) {
-      if (metadatum.key === 'dc.type') {
-        isDissertation = metadatum.value.toLowerCase() === 'thesis';
-        break;
-      }
-    }
-    return isDissertation;
+    return this.hasType('thesis');
  }

  /**
@@ -318,40 +315,15 @@ export class MetadataService {
   *      true if this._item has a dc.type equal to 'Technical Report'
   */
  private isTechReport(): boolean {
-    let isTechReport = false;
-    for (const metadatum of this.currentObject.value.metadata) {
-      if (metadatum.key === 'dc.type') {
-        isTechReport = metadatum.value.toLowerCase() === 'technical report';
-        break;
-      }
-    }
-    return isTechReport;
+    return this.hasType('technical report');
  }

  private getMetaTagValue(key: string): string {
-    let value: string;
-    for (const metadatum of this.currentObject.value.metadata) {
-      if (metadatum.key === key) {
-        value = metadatum.value;
-      }
-    }
-    return value;
+    return this.currentObject.value.firstMetadataValue(key);
  }

  private getFirstMetaTagValue(keys: string[]): string {
-    let value: string;
-    for (const metadatum of this.currentObject.value.metadata) {
-      for (const key of keys) {
-        if (key === metadatum.key) {
-          value = metadatum.value;
-          break;
-        }
-      }
-      if (value !== undefined) {
-        break;
-      }
-    }
-    return value;
+    return this.currentObject.value.firstMetadataValue(keys);
  }

  private getMetaTagValuesAndCombine(key: string): string {
@@ -359,15 +331,7 @@ export class MetadataService {
  }

  private getMetaTagValues(keys: string[]): string[] {
-    const values: string[] = [];
-    for (const metadatum of this.currentObject.value.metadata) {
-      for (const key of keys) {
-        if (key === metadatum.key) {
-          values.push(metadatum.value);
-        }
-      }
-    }
-    return values;
+    return this.currentObject.value.allMetadataValues(keys);
  }

  private addMetaTag(property: string, content: string): void {
--- a/src/app/core/shared/collection.model.ts
+++ b/src/app/core/shared/collection.model.ts
@@ -16,7 +16,7 @@ export class Collection extends DSpaceObject {
   * Corresponds to the metadata field dc.description
   */
  get introductoryText(): string {
-    return this.findMetadata('dc.description');
+    return this.firstMetadataValue('dc.description');
  }

  /**
@@ -24,7 +24,7 @@ export class Collection extends DSpaceObject {
   * Corresponds to the metadata field dc.description.abstract
   */
  get shortDescription(): string {
-    return this.findMetadata('dc.description.abstract');
+    return this.firstMetadataValue('dc.description.abstract');
  }

  /**
@@ -32,7 +32,7 @@ export class Collection extends DSpaceObject {
   * Corresponds to the metadata field dc.rights
   */
  get copyrightText(): string {
-    return this.findMetadata('dc.rights');
+    return this.firstMetadataValue('dc.rights');
  }

  /**
@@ -40,7 +40,7 @@ export class Collection extends DSpaceObject {
   * Corresponds to the metadata field dc.rights.license
   */
  get license(): string {
-    return this.findMetadata('dc.rights.license');
+    return this.firstMetadataValue('dc.rights.license');
  }

  /**
@@ -48,7 +48,7 @@ export class Collection extends DSpaceObject {
   * Corresponds to the metadata field dc.description.tableofcontents
   */
  get sidebarText(): string {
-    return this.findMetadata('dc.description.tableofcontents');
+    return this.firstMetadataValue('dc.description.tableofcontents');
  }

  /**
--- a/src/app/core/shared/community.model.ts
+++ b/src/app/core/shared/community.model.ts
@@ -17,7 +17,7 @@ export class Community extends DSpaceObject {
   * Corresponds to the metadata field dc.description
   */
  get introductoryText(): string {
-    return this.findMetadata('dc.description');
+    return this.firstMetadataValue('dc.description');
  }

  /**
@@ -25,7 +25,7 @@ export class Community extends DSpaceObject {
   * Corresponds to the metadata field dc.description.abstract
   */
  get shortDescription(): string {
-    return this.findMetadata('dc.description.abstract');
+    return this.firstMetadataValue('dc.description.abstract');
  }

  /**
@@ -33,7 +33,7 @@ export class Community extends DSpaceObject {
   * Corresponds to the metadata field dc.rights
   */
  get copyrightText(): string {
-    return this.findMetadata('dc.rights');
+    return this.firstMetadataValue('dc.rights');
  }

  /**
@@ -41,7 +41,7 @@ export class Community extends DSpaceObject {
   * Corresponds to the metadata field dc.description.tableofcontents
   */
  get sidebarText(): string {
-    return this.findMetadata('dc.description.tableofcontents');
+    return this.firstMetadataValue('dc.description.tableofcontents');
  }

  /**
--- a/src/app/core/shared/dspace-object.model.ts
+++ b/src/app/core/shared/dspace-object.model.ts
@@ -1,5 +1,5 @@
-import { Metadatum } from './metadatum.model'
-import { isEmpty, isNotEmpty } from '../../shared/empty.util';
+import { MetadataMap, MetadataValue, MetadataValueFilter } from './metadata.interfaces';
+import { Metadata } from './metadata.model';
 import { CacheableObject } from '../cache/object-cache.reducer';
 import { RemoteData } from '../data/remote-data';
 import { ResourceType } from './resource-type';
@@ -35,14 +35,14 @@ export class DSpaceObject implements CacheableObject, ListableObject {
   * The name for this DSpaceObject
   */
  get name(): string {
-    return this.findMetadata('dc.title');
+    return this.firstMetadataValue('dc.title');
  }

  /**
-   * An array containing all metadata of this DSpaceObject
+   * All metadata of this DSpaceObject
   */
  @autoserialize
-  metadata: Metadatum[] = [];
+  metadata: MetadataMap;

  /**
   * An array of DSpaceObjects that are direct parents of this DSpaceObject
@@ -55,41 +55,58 @@ export class DSpaceObject implements CacheableObject, ListableObject {
  owner: Observable<RemoteData<DSpaceObject>>;

  /**
-   * Find a metadata field by key and language
+   * Gets all matching metadata in this DSpaceObject.
   *
-   * This method returns the value of the first element
-   * in the metadata array that matches the provided
-   * key and language
-   *
-   * @param key
-   * @param language
-   * @return string
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {MetadataValue[]} the matching values or an empty array.
   */
-  findMetadata(key: string, language?: string): string {
-    const metadatum = this.metadata.find((m: Metadatum) => {
-      return m.key === key && (isEmpty(language) || m.language === language)
-    });
-    if (isNotEmpty(metadatum)) {
-      return metadatum.value;
-    } else {
-      return undefined;
-    }
+  allMetadata(keyOrKeys: string | string[], valueFilter?: MetadataValueFilter): MetadataValue[] {
+    return Metadata.all(this.metadata, keyOrKeys, valueFilter);
  }

  /**
-   * Find metadata by an array of keys
+   * Like [[allMetadata]], but only returns string values.
   *
-   * This method returns the values of the element
-   * in the metadata array that match the provided
-   * key(s)
-   *
-   * @param key(s)
-   * @return Array<Metadatum>
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {string[]} the matching string values or an empty array.
   */
-  filterMetadata(keys: string[]): Metadatum[] {
-    return this.metadata.filter((metadatum: Metadatum) => {
-      return keys.some((key) => key === metadatum.key);
-    });
+  allMetadataValues(keyOrKeys: string | string[], valueFilter?: MetadataValueFilter): string[] {
+    return Metadata.allValues(this.metadata, keyOrKeys, valueFilter);
+  }
+
+  /**
+   * Gets the first matching MetadataValue object in this DSpaceObject, or `undefined`.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {MetadataValue} the first matching value, or `undefined`.
+   */
+  firstMetadata(keyOrKeys: string | string[], valueFilter?: MetadataValueFilter): MetadataValue {
+    return Metadata.first(this.metadata, keyOrKeys, valueFilter);
+  }
+
+  /**
+   * Like [[firstMetadata]], but only returns a string value, or `undefined`.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {string} the first matching string value, or `undefined`.
+   */
+  firstMetadataValue(keyOrKeys: string | string[], valueFilter?: MetadataValueFilter): string {
+    return Metadata.firstValue(this.metadata, keyOrKeys, valueFilter);
+  }
+
+  /**
+   * Checks for a matching metadata value in this DSpaceObject.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {boolean} whether a match is found.
+   */
+  hasMetadata(keyOrKeys: string | string[], valueFilter?: MetadataValueFilter): boolean {
+    return Metadata.has(this.metadata, keyOrKeys, valueFilter);
  }

 }
--- a/src/app/core/shared/metadata.interfaces.ts
+++ b/src/app/core/shared/metadata.interfaces.ts
@@ -0,0 +1,30 @@
+/** A map of metadata keys to an ordered list of MetadataValue objects. */
+export interface MetadataMap {
+  [ key: string ]: MetadataValue[];
+}
+
+/** A single metadata value and its properties. */
+export interface MetadataValue {
+
+  /** The language. */
+  language: string;
+
+  /** The string value. */
+  value: string;
+}
+
+/** Constraints for matching metadata values. */
+export interface MetadataValueFilter {
+
+  /** The language constraint. */
+  language?: string;
+
+  /** The value constraint. */
+  value?: string;
+
+  /** Whether the value constraint should match without regard to case. */
+  ignoreCase?: boolean;
+
+  /** Whether the value constraint should match as a substring. */
+  substring?: boolean;
+}
--- a/src/app/core/shared/metadata.model.spec.ts
+++ b/src/app/core/shared/metadata.model.spec.ts
@@ -0,0 +1,175 @@
+import { isUndefined } from '../../shared/empty.util';
+import { MetadataValue, MetadataValueFilter } from './metadata.interfaces';
+import { Metadata } from './metadata.model';
+
+const mdValue = (value: string, language?: string): MetadataValue => {
+  return { value: value, language: isUndefined(language) ? null : language };
+}
+
+const dcDescription = mdValue('Some description');
+const dcAbstract = mdValue('Some abstract');
+const dcTitle0 = mdValue('Title 0');
+const dcTitle1 = mdValue('Title 1');
+const dcTitle2 = mdValue('Title 2', 'en_US');
+const bar = mdValue('Bar');
+
+const singleMap = { 'dc.title': [ dcTitle0 ] };
+
+const multiMap = {
+  'dc.description': [ dcDescription ],
+  'dc.description.abstract': [ dcAbstract ],
+  'dc.title': [ dcTitle1, dcTitle2 ],
+  'foo': [ bar ]
+};
+
+const testMethod = (fn, resultKind, mapOrMaps, keyOrKeys, expected, filter?) => {
+  const keys = keyOrKeys instanceof Array ? keyOrKeys : [ keyOrKeys ];
+  describe('and key' + (keys.length === 1 ? (' ' + keys[0]) : ('s ' + JSON.stringify(keys)))
+        + ' with ' + (isUndefined(filter) ? 'no filter' : 'filter ' + JSON.stringify(filter)), () => {
+    const result = fn(mapOrMaps, keys, filter);
+    let shouldReturn;
+    if (resultKind === 'boolean') {
+      shouldReturn = expected;
+    } else if (isUndefined(expected)) {
+      shouldReturn = 'undefined';
+    } else if (expected instanceof Array) {
+      shouldReturn = 'an array with ' + expected.length + ' ' + (expected.length > 1 ? 'ordered ' : '')
+          + resultKind + (expected.length !== 1 ? 's' : '');
+    } else {
+      shouldReturn = 'a ' + resultKind;
+    }
+    it('should return ' + shouldReturn, () => {
+      expect(result).toEqual(expected);
+    });
+  })
+};
+
+describe('Metadata', () => {
+
+  describe('all method', () => {
+
+    const testAll = (mapOrMaps, keyOrKeys, expected, filter?: MetadataValueFilter) =>
+      testMethod(Metadata.all, 'value', mapOrMaps, keyOrKeys, expected, filter);
+
+    describe('with emptyMap', () => {
+      testAll({}, 'foo', []);
+      testAll({}, '*', []);
+    });
+    describe('with singleMap', () => {
+      testAll(singleMap, 'foo', []);
+      testAll(singleMap, '*', [ dcTitle0 ]);
+      testAll(singleMap, '*', [], { value: 'baz' });
+      testAll(singleMap, 'dc.title', [ dcTitle0 ]);
+      testAll(singleMap, 'dc.*', [ dcTitle0 ]);
+    });
+    describe('with multiMap', () => {
+      testAll(multiMap, 'foo', [ bar ]);
+      testAll(multiMap, '*', [ dcDescription, dcAbstract, dcTitle1, dcTitle2, bar ]);
+      testAll(multiMap, 'dc.title', [ dcTitle1, dcTitle2 ]);
+      testAll(multiMap, 'dc.*', [ dcDescription, dcAbstract, dcTitle1, dcTitle2 ]);
+      testAll(multiMap, [ 'dc.title', 'dc.*' ], [ dcTitle1, dcTitle2, dcDescription, dcAbstract ]);
+    });
+    describe('with [ singleMap, multiMap ]', () => {
+      testAll([ singleMap, multiMap ], 'foo', [ bar ]);
+      testAll([ singleMap, multiMap ], '*', [ dcTitle0 ]);
+      testAll([ singleMap, multiMap ], 'dc.title', [ dcTitle0 ]);
+      testAll([ singleMap, multiMap ], 'dc.*', [ dcTitle0 ]);
+    });
+    describe('with [ multiMap, singleMap ]', () => {
+      testAll([ multiMap, singleMap ], 'foo', [ bar ]);
+      testAll([ multiMap, singleMap ], '*', [ dcDescription, dcAbstract, dcTitle1, dcTitle2, bar ]);
+      testAll([ multiMap, singleMap ], 'dc.title', [ dcTitle1, dcTitle2 ]);
+      testAll([ multiMap, singleMap ], 'dc.*', [ dcDescription, dcAbstract, dcTitle1, dcTitle2 ]);
+      testAll([ multiMap, singleMap ], [ 'dc.title', 'dc.*' ], [ dcTitle1, dcTitle2, dcDescription, dcAbstract ]);
+    });
+  });
+
+  describe('allValues method', () => {
+
+    const testAllValues = (mapOrMaps, keyOrKeys, expected) =>
+      testMethod(Metadata.allValues, 'string', mapOrMaps, keyOrKeys, expected);
+
+    describe('with emptyMap', () => {
+      testAllValues({}, '*', []);
+    });
+    describe('with singleMap', () => {
+      testAllValues([ singleMap, multiMap ], '*', [ dcTitle0.value ]);
+    });
+    describe('with [ multiMap, singleMap ]', () => {
+      testAllValues([ multiMap, singleMap ], '*', [ dcDescription.value, dcAbstract.value, dcTitle1.value, dcTitle2.value, bar.value ]);
+    });
+  });
+
+  describe('first method', () => {
+
+    const testFirst = (mapOrMaps, keyOrKeys, expected) =>
+      testMethod(Metadata.first, 'value', mapOrMaps, keyOrKeys, expected);
+
+    describe('with emptyMap', () => {
+      testFirst({}, '*', undefined);
+    });
+    describe('with singleMap', () => {
+      testFirst(singleMap, '*', dcTitle0);
+    });
+    describe('with [ multiMap, singleMap ]', () => {
+      testFirst([ multiMap, singleMap ], '*', dcDescription);
+    });
+  });
+
+  describe('firstValue method', () => {
+
+    const testFirstValue = (mapOrMaps, keyOrKeys, expected) =>
+      testMethod(Metadata.firstValue, 'value', mapOrMaps, keyOrKeys, expected);
+
+    describe('with emptyMap', () => {
+      testFirstValue({}, '*', undefined);
+    });
+    describe('with singleMap', () => {
+      testFirstValue(singleMap, '*', dcTitle0.value);
+    });
+    describe('with [ multiMap, singleMap ]', () => {
+      testFirstValue([ multiMap, singleMap ], '*', dcDescription.value);
+    });
+  });
+
+  describe('has method', () => {
+
+    const testHas = (mapOrMaps, keyOrKeys, expected, filter?: MetadataValueFilter) =>
+      testMethod(Metadata.has, 'boolean', mapOrMaps, keyOrKeys, expected, filter);
+
+    describe('with emptyMap', () => {
+      testHas({}, '*', false);
+    });
+    describe('with singleMap', () => {
+      testHas(singleMap, '*', true);
+      testHas(singleMap, '*', false, { value: 'baz' });
+    });
+    describe('with [ multiMap, singleMap ]', () => {
+      testHas([ multiMap, singleMap ], '*', true);
+    });
+  });
+
+  describe('valueMatches method', () => {
+
+    const testValueMatches = (value: MetadataValue, expected: boolean, filter?: MetadataValueFilter) => {
+      describe('with value ' + JSON.stringify(value) + ' and filter '
+          + (isUndefined(filter) ? 'undefined' : JSON.stringify(filter)), () => {
+        const result = Metadata.valueMatches(value, filter);
+        it('should return ' + expected, () => {
+          expect(result).toEqual(expected);
+        });
+      });
+    };
+
+    testValueMatches(mdValue('a'), true);
+    testValueMatches(mdValue('a'), true, { value: 'a' });
+    testValueMatches(mdValue('a'), false, { value: 'A' });
+    testValueMatches(mdValue('a'), true, { value: 'A', ignoreCase: true });
+    testValueMatches(mdValue('ab'), false, { value: 'b' });
+    testValueMatches(mdValue('ab'), true, { value: 'b', substring: true });
+    testValueMatches(mdValue('a'), true, { language: null });
+    testValueMatches(mdValue('a'), false, { language: 'en_US' });
+    testValueMatches(mdValue('a', 'en_US'), true, { language: 'en_US' });
+  });
+
+});
--- a/src/app/core/shared/metadata.model.ts
+++ b/src/app/core/shared/metadata.model.ts
@@ -0,0 +1,163 @@
+import { isEmpty, isNotUndefined, isUndefined } from '../../shared/empty.util';
+import { MetadataMap, MetadataValue, MetadataValueFilter } from './metadata.interfaces';
+
+/**
+ * Utility class for working with DSpace object metadata.
+ *
+ * When specifying metadata keys, wildcards are supported, so `'*'` will match all keys, `'dc.date.*'` will
+ * match all qualified dc dates, and so on. Exact keys will be evaluated (and matches returned) in the order
+ * they are given.
+ *
+ * When multiple keys in a map match a given wildcard, they are evaluated in the order they are stored in
+ * the map (alphanumeric if obtained from the REST api). If duplicate or overlapping keys are specified, the
+ * first one takes precedence. For example, specifying `['dc.date', 'dc.*', '*']` will cause any `dc.date`
+ * values to be evaluated (and returned, if matched) first, followed by any other `dc` metadata values,
+ * followed by any other (non-dc) metadata values.
+ */
+export class Metadata {
+
+  /**
+   * Gets all matching metadata in the map(s).
+   *
+   * @param {MetadataMap|MetadataMap[]} mapOrMaps The source map(s). When multiple maps are given, they will be
+   * checked in order, and only values from the first with at least one match will be returned.
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see above.
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {MetadataValue[]} the matching values or an empty array.
+   */
+  public static all(mapOrMaps: MetadataMap | MetadataMap[], keyOrKeys: string | string[],
+                    filter?: MetadataValueFilter): MetadataValue[] {
+    const mdMaps: MetadataMap[] = mapOrMaps instanceof Array ? mapOrMaps : [ mapOrMaps ];
+    const matches: MetadataValue[] = [];
+    for (const mdMap of mdMaps) {
+      for (const mdKey of Metadata.resolveKeys(mdMap, keyOrKeys)) {
+        const candidates = mdMap[mdKey];
+        if (candidates) {
+          for (const candidate of candidates) {
+            if (Metadata.valueMatches(candidate, filter)) {
+              matches.push(candidate);
+            }
+          }
+        }
+      }
+      if (!isEmpty(matches)) {
+        return matches;
+      }
+    }
+    return matches;
+  }
+
+  /**
+   * Like [[Metadata.all]], but only returns string values.
+   *
+   * @param {MetadataMap|MetadataMap[]} mapOrMaps The source map(s). When multiple maps are given, they will be
+   * checked in order, and only values from the first with at least one match will be returned.
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see above.
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {string[]} the matching string values or an empty array.
+   */
+  public static allValues(mapOrMaps: MetadataMap | MetadataMap[], keyOrKeys: string | string[],
+                          filter?: MetadataValueFilter): string[] {
+    return Metadata.all(mapOrMaps, keyOrKeys, filter).map((mdValue) => mdValue.value);
+  }
+
+  /**
+   * Gets the first matching MetadataValue object in the map(s), or `undefined`.
+   *
+   * @param {MetadataMap|MetadataMap[]} mapOrMaps The source map(s).
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see above.
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {MetadataValue} the first matching value, or `undefined`.
+   */
+  public static first(mdMapOrMaps: MetadataMap | MetadataMap[], keyOrKeys: string | string[],
+                      filter?: MetadataValueFilter): MetadataValue {
+    const mdMaps: MetadataMap[] = mdMapOrMaps instanceof Array ? mdMapOrMaps : [ mdMapOrMaps ];
+    for (const mdMap of mdMaps) {
+      for (const key of Metadata.resolveKeys(mdMap, keyOrKeys)) {
+        const values: MetadataValue[] = mdMap[key];
+        if (values) {
+          return values.find((value: MetadataValue) => Metadata.valueMatches(value, filter));
+        }
+      }
+    }
+  }
+
+  /**
+   * Like [[Metadata.first]], but only returns a string value, or `undefined`.
+   *
+   * @param {MetadataMap|MetadataMap[]} mapOrMaps The source map(s).
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see above.
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {string} the first matching string value, or `undefined`.
+   */
+  public static firstValue(mdMapOrMaps: MetadataMap | MetadataMap[], keyOrKeys: string | string[],
+                           filter?: MetadataValueFilter): string {
+    const value = Metadata.first(mdMapOrMaps, keyOrKeys, filter);
+    return isUndefined(value) ? undefined : value.value;
+  }
+
+  /**
+   * Checks for a matching metadata value in the given map(s).
+   *
+   * @param {MetadataMap|MetadataMap[]} mapOrMaps The source map(s).
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see above.
+   * @param {MetadataValueFilter} filter The value filter to use. If unspecified, no filtering will be done.
+   * @returns {boolean} whether a match is found.
+   */
+  public static has(mdMapOrMaps: MetadataMap | MetadataMap[], keyOrKeys: string | string[],
+                    filter?: MetadataValueFilter): boolean {
+    return isNotUndefined(Metadata.first(mdMapOrMaps, keyOrKeys, filter));
+  }
+
+  /**
+   * Checks if a value matches a filter.
+   *
+   * @param {MetadataValue} mdValue the value to check.
+   * @param {MetadataValueFilter} filter the filter to use.
+   * @returns {boolean} whether the filter matches, or true if no filter is given.
+   */
+  public static valueMatches(mdValue: MetadataValue, filter: MetadataValueFilter) {
+    if (!filter) {
+      return true;
+    } else if (filter.language && filter.language !== mdValue.language) {
+      return false;
+    } else if (filter.value) {
+      let fValue = filter.value;
+      let mValue = mdValue.value;
+      if (filter.ignoreCase) {
+        fValue = filter.value.toLowerCase();
+        mValue = mdValue.value.toLowerCase();
+      }
+      if (filter.substring) {
+        return mValue.includes(fValue);
+      } else {
+        return mValue === fValue;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Gets the list of keys in the map limited by, and in the order given by `keyOrKeys`.
+   *
+   * @param {MetadataMap} mdMap The source map.
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see above.
+   */
+  private static resolveKeys(mdMap: MetadataMap, keyOrKeys: string | string[]): string[] {
+    const inputKeys: string[] = keyOrKeys instanceof Array ? keyOrKeys : [ keyOrKeys ];
+    const outputKeys: string[] = [];
+    for (const inputKey of inputKeys) {
+      if (inputKey.includes('*')) {
+        const inputKeyRegex = new RegExp('^' + inputKey.replace('.', '\.').replace('*', '.*') + '$');
+        for (const mapKey of Object.keys(mdMap)) {
+          if (!outputKeys.includes(mapKey) && inputKeyRegex.test(mapKey)) {
+            outputKeys.push(mapKey);
+          }
+        }
+      } else if (mdMap.hasOwnProperty(inputKey) && !outputKeys.includes(inputKey)) {
+        outputKeys.push(inputKey);
+      }
+    }
+    return outputKeys;
+  }
+}
--- a/src/app/core/shared/metadatum.model.ts
+++ b/src/app/core/shared/metadatum.model.ts
@@ -1,23 +0,0 @@
-import { autoserialize } from 'cerialize';
-
-export class Metadatum {
-
-  /**
-   * The metadata field of this Metadatum
-   */
-  @autoserialize
-  key: string;
-
-  /**
-   * The language of this Metadatum
-   */
-  @autoserialize
-  language: string;
-
-  /**
-   * The value of this Metadatum
-   */
-  @autoserialize
-  value: string;
-
-}
--- a/src/app/shared/comcol-forms/comcol-form/comcol-form.component.spec.ts
+++ b/src/app/shared/comcol-forms/comcol-form/comcol-form.component.spec.ts
@@ -11,7 +11,6 @@ import { ResourceType } from '../../../core/shared/resource-type';
 import { ComColFormComponent } from './comcol-form.component';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
 import { hasValue } from '../../empty.util';
-import { Metadatum } from '../../../core/shared/metadatum.model';

 describe('ComColFormComponent', () => {
  let comp: ComColFormComponent<DSpaceObject>;
@@ -29,23 +28,24 @@ describe('ComColFormComponent', () => {
      return undefined;
    }
  };
-  const titleMD = { key: 'dc.title', value: 'Community Title' } as Metadatum;
-  const randomMD = { key: 'dc.random', value: 'Random metadata excluded from form' } as Metadatum;
-  const abstractMD = {
-    key: 'dc.description.abstract',
-    value: 'Community description'
-  } as Metadatum;
-  const newTitleMD = { key: 'dc.title', value: 'New Community Title' } as Metadatum;
+  const dcTitle = 'dc.title';
+  const dcRandom = 'dc.random';
+  const dcAbstract = 'dc.description.abstract';
+
+  const titleMD = { [dcTitle]: [ { value: 'Community Title', language: null } ] };
+  const randomMD = { [dcRandom]: [ { value: 'Random metadata excluded from form', language: null } ] };
+  const abstractMD = { [dcAbstract]: [ { value: 'Community description', language: null } ] };
+  const newTitleMD = { [dcTitle]: [ { value: 'New Community Title', language: null } ] };
  const formModel = [
    new DynamicInputModel({
      id: 'title',
-      name: newTitleMD.key,
-      value: 'New Community Title'
+      name: dcTitle,
+      value: newTitleMD[dcTitle][0].value
    }),
    new DynamicInputModel({
      id: 'abstract',
-      name: abstractMD.key,
-      value: abstractMD.value
+      name: dcAbstract,
+      value: abstractMD[dcAbstract][0].value
    })
  ];

@@ -87,10 +87,10 @@ describe('ComColFormComponent', () => {
      comp.dso = Object.assign(
        new Community(),
        {
-          metadata: [
-            titleMD,
-            randomMD
-          ]
+          metadata: {
+            ...titleMD,
+            ...randomMD
+          }
        }
      );

@@ -101,11 +101,11 @@ describe('ComColFormComponent', () => {
          {},
          new Community(),
          {
-            metadata: [
-              randomMD,
-              newTitleMD,
-              abstractMD
-            ],
+            metadata: {
+              ...newTitleMD,
+              ...randomMD,
+              ...abstractMD
+            },
            type: ResourceType.Community
          },
        )
--- a/src/app/shared/comcol-forms/comcol-form/comcol-form.component.ts
+++ b/src/app/shared/comcol-forms/comcol-form/comcol-form.component.ts
@@ -8,6 +8,7 @@ import { FormGroup } from '@angular/forms';
 import { DynamicFormControlModel } from '@ng-dynamic-forms/core/src/model/dynamic-form-control.model';
 import { TranslateService } from '@ngx-translate/core';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
+import { MetadataMap, MetadataValue } from '../../../core/shared/metadata.interfaces';
 import { isNotEmpty } from '../../empty.util';
 import { ResourceType } from '../../../core/shared/resource-type';

@@ -64,7 +65,7 @@ export class ComColFormComponent<T extends DSpaceObject> implements OnInit {
  ngOnInit(): void {
    this.formModel.forEach(
      (fieldModel: DynamicInputModel) => {
-        fieldModel.value = this.dso.findMetadata(fieldModel.name);
+        fieldModel.value = this.dso.firstMetadataValue(fieldModel.name);
      }
    );
    this.formGroup = this.formService.createFormGroup(this.formModel);
@@ -77,20 +78,24 @@ export class ComColFormComponent<T extends DSpaceObject> implements OnInit {
  }

  /**
-   * Checks which new fields where added and sends the updated version of the DSO to the parent component
+   * Checks which new fields were added and sends the updated version of the DSO to the parent component
   */
  onSubmit() {
-    const metadata = this.formModel.map(
-      (fieldModel: DynamicInputModel) => {
-        return { key: fieldModel.name, value: fieldModel.value }
+    const formMetadata = new Object() as MetadataMap;
+    this.formModel.forEach((fieldModel: DynamicInputModel) => {
+      const value: MetadataValue = { value: fieldModel.value as string, language: null };
+      if (formMetadata.hasOwnProperty(fieldModel.name)) {
+        formMetadata[fieldModel.name].push(value);
+      } else {
+        formMetadata[fieldModel.name] = [ value ];
      }
-    );
-    const filteredOldMetadata = this.dso.metadata.filter((filter) => !metadata.map((md) => md.key).includes(filter.key));
-    const filteredNewMetadata = metadata.filter((md) => isNotEmpty(md.value));
+    });

-    const newMetadata = [...filteredOldMetadata, ...filteredNewMetadata];
    const updatedDSO = Object.assign({}, this.dso, {
-      metadata: newMetadata,
+      metadata: {
+        ...this.dso.metadata,
+        ...formMetadata
+      },
      type: ResourceType.Community
    });
    this.submitForm.emit(updatedDSO);
--- a/src/app/shared/mocks/mock-item.ts
+++ b/src/app/shared/mocks/mock-item.ts
@@ -51,13 +51,14 @@ export const MockItem: Item = Object.assign(new Item(), {
          id: 'cf9b0c8e-a1eb-4b65-afd0-567366448713',
          uuid: 'cf9b0c8e-a1eb-4b65-afd0-567366448713',
          type: 'bitstream',
-          metadata: [
+          metadata: {
+            'dc.title': [
              {
-              key: 'dc.title',
                language: null,
                value: 'test_word.docx'
              }
            ]
+          }
        },
        {
          sizeBytes: 31302,
@@ -85,14 +86,15 @@ export const MockItem: Item = Object.assign(new Item(), {
          id: '99b00f3c-1cc6-4689-8158-91965bee6b28',
          uuid: '99b00f3c-1cc6-4689-8158-91965bee6b28',
          type: 'bitstream',
-          metadata: [
+          metadata: {
+            'dc.title': [
              {
-              key: 'dc.title',
                language: null,
                value: 'test_pdf.pdf'
              }
            ]
          }
+        }
      ]
    }
  }),
@@ -100,98 +102,106 @@ export const MockItem: Item = Object.assign(new Item(), {
  id: '0ec7ff22-f211-40ab-a69e-c819b0b1f357',
  uuid: '0ec7ff22-f211-40ab-a69e-c819b0b1f357',
  type: 'item',
-  metadata: [
+  metadata: {
+    'dc.creator': [
      {
-      key: 'dc.creator',
        language: 'en_US',
        value: 'Doe, Jane'
-    },
+      }
+    ],
+    'dc.date.accessioned': [
      {
-      key: 'dc.date.accessioned',
        language: null,
        value: '1650-06-26T19:58:25Z'
-    },
+      }
+    ],
+    'dc.date.available': [
      {
-      key: 'dc.date.available',
        language: null,
        value: '1650-06-26T19:58:25Z'
-    },
+      }
+    ],
+    'dc.date.issued': [
      {
-      key: 'dc.date.issued',
        language: null,
        value: '1650-06-26'
-    },
+      }
+    ],
+    'dc.identifier.issn': [
      {
-      key: 'dc.identifier.issn',
        language: 'en_US',
        value: '123456789'
-    },
+      }
+    ],
+    'dc.identifier.uri': [
      {
-      key: 'dc.identifier.uri',
        language: null,
        value: 'http://dspace7.4science.it/xmlui/handle/10673/6'
-    },
+      }
+    ],
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'This is really just a sample abstract. If it was a real abstract it would contain useful information about this test document. Sorry though, nothing useful in this paragraph. You probably shouldn\'t have even bothered to read it!'
-    },
+      }
+    ],
+    'dc.description.provenance': [
      {
-      key: 'dc.description.provenance',
        language: 'en',
        value: 'Made available in DSpace on 2012-06-26T19:58:25Z (GMT). No. of bitstreams: 2\r\ntest_ppt.ppt: 12707328 bytes, checksum: a353fc7d29b3c558c986f7463a41efd3 (MD5)\r\ntest_ppt.pptx: 12468572 bytes, checksum: 599305edb4ebee329667f2c35b14d1d6 (MD5)'
      },
      {
-      key: 'dc.description.provenance',
        language: 'en',
        value: 'Restored into DSpace on 2013-06-13T09:17:34Z (GMT).'
      },
      {
-      key: 'dc.description.provenance',
        language: 'en',
        value: 'Restored into DSpace on 2013-06-13T11:04:16Z (GMT).'
      },
      {
-      key: 'dc.description.provenance',
        language: 'en',
        value: 'Restored into DSpace on 2017-04-24T19:44:08Z (GMT).'
-    },
+      }
+    ],
+    'dc.language': [
      {
-      key: 'dc.language',
        language: 'en_US',
        value: 'en'
-    },
+      }
+    ],
+    'dc.rights': [
      {
-      key: 'dc.rights',
        language: 'en_US',
        value: '© Jane Doe'
-    },
+      }
+    ],
+    'dc.subject': [
      {
-      key: 'dc.subject',
        language: 'en_US',
        value: 'keyword1'
      },
      {
-      key: 'dc.subject',
        language: 'en_US',
        value: 'keyword2'
      },
      {
-      key: 'dc.subject',
        language: 'en_US',
        value: 'keyword3'
-    },
+      }
+    ],
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test PowerPoint Document'
-    },
+      }
+    ],
+    'dc.type': [
      {
-      key: 'dc.type',
        language: 'en_US',
        value: 'text'
      }
-  ],
+    ]
+  },
  owningCollection: observableOf({
      self: 'https://dspace7.4science.it/dspace-spring-rest/api/core/collections/1c11f3f1-ba1f-4f36-908a-3f1ea9a557eb',
      requestPending: false,
--- a/src/app/shared/object-collection/shared/object-collection-element/abstract-listable-element.component.ts
+++ b/src/app/shared/object-collection/shared/object-collection-element/abstract-listable-element.component.ts
@@ -1,6 +1,5 @@
 import { Component, Inject } from '@angular/core';
 import { ListableObject } from '../listable-object.model';
-import { hasValue } from '../../../empty.util';

@Component({
  selector: 'ds-abstract-object-element',
@@ -11,8 +10,4 @@ export class AbstractListableElementComponent <T extends ListableObject> {
  public constructor(@Inject('objectElementProvider') public listableObject: ListableObject) {
    this.object = listableObject as T;
  }
-
-  hasValue(data) {
-    return hasValue(data);
-  }
 }
--- a/src/app/shared/object-grid/collection-grid-element/collection-grid-element.component.spec.ts
+++ b/src/app/shared/object-grid/collection-grid-element/collection-grid-element.component.spec.ts
@@ -8,21 +8,25 @@ let collectionGridElementComponent: CollectionGridElementComponent;
 let fixture: ComponentFixture<CollectionGridElementComponent>;

 const mockCollectionWithAbstract: Collection = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    }]
+      }
+    ]
+  }
 });

 const mockCollectionWithoutAbstract: Collection = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    }]
+      }
+    ]
+  }
 });

 describe('CollectionGridElementComponent', () => {
--- a/src/app/shared/object-grid/community-grid-element/community-grid-element.component.spec.ts
+++ b/src/app/shared/object-grid/community-grid-element/community-grid-element.component.spec.ts
@@ -8,21 +8,25 @@ let communityGridElementComponent: CommunityGridElementComponent;
 let fixture: ComponentFixture<CommunityGridElementComponent>;

 const mockCommunityWithAbstract: Community = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    }]
+      }
+    ]
+  }
 });

 const mockCommunityWithoutAbstract: Community = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    }]
+      }
+    ]
+  }
 });

 describe('CommunityGridElementComponent', () => {
--- a/src/app/shared/object-grid/item-grid-element/item-grid-element.component.html
+++ b/src/app/shared/object-grid/item-grid-element/item-grid-element.component.html
@@ -5,19 +5,19 @@
      </ds-grid-thumbnail>
    </a>
    <div class="card-body">
-      <h4 class="card-title">{{object.findMetadata('dc.title')}}</h4>
+      <h4 class="card-title">{{object.firstMetadataValue('dc.title')}}</h4>

      <ds-truncatable-part [id]="object.id" [minLines]="2">
-        <p *ngIf="object.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']).length > 0" class="item-authors card-text text-muted">
-            <span *ngFor="let authorMd of object.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']); let last=last;">{{authorMd.value}}
+        <p *ngIf="object.hasMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])" class="item-authors card-text text-muted">
+            <span *ngFor="let author of object.allMetadataValues(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']); let last=last;">{{author}}
                <span *ngIf="!last">; </span>
            </span>
-          <span *ngIf="hasValue(object.findMetadata('dc.date.issued'))" class="item-date">{{object.findMetadata("dc.date.issued")}}</span>
+          <span *ngIf="object.hasMetadata('dc.date.issued')" class="item-date">{{object.firstMetadataValue("dc.date.issued")}}</span>
        </p>
      </ds-truncatable-part>

      <ds-truncatable-part [id]="object.id" [minLines]="5">
-        <p *ngIf="object.findMetadata('dc.description.abstract')" class="item-abstract card-text">{{object.findMetadata("dc.description.abstract") }}</p>
+        <p *ngIf="object.hasMetadata('dc.description.abstract')" class="item-abstract card-text">{{object.firstMetadataValue("dc.description.abstract")}}</p>
      </ds-truncatable-part>

      <div class="text-center pt-2">
--- a/src/app/shared/object-grid/item-grid-element/item-grid-element.component.spec.ts
+++ b/src/app/shared/object-grid/item-grid-element/item-grid-element.component.spec.ts
@@ -11,31 +11,37 @@ let fixture: ComponentFixture<ItemGridElementComponent>;

 const mockItemWithAuthorAndDate: Item = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.contributor.author': [
      {
-      key: 'dc.contributor.author',
        language: 'en_US',
        value: 'Smith, Donald'
-    },
+      }
+    ],
+    'dc.date.issued': [
      {
-      key: 'dc.date.issued',
        language: null,
        value: '2015-06-26'
-    }]
+      }
+    ]
+  }
 });
 const mockItemWithoutAuthorAndDate: Item = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'This is just another title'
-    },
+      }
+    ],
+    'dc.type': [
      {
-      key: 'dc.type',
        language: null,
        value: 'Article'
-    }]
+      }
+    ]
+  }
 });

 describe('ItemGridElementComponent', () => {
--- a/src/app/shared/object-grid/search-result-grid-element/collection-search-result/collection-search-result-grid-element.component.spec.ts
+++ b/src/app/shared/object-grid/search-result-grid-element/collection-search-result/collection-search-result-grid-element.component.spec.ts
@@ -16,25 +16,29 @@ const truncatableServiceStub: any = {
 };

 const mockCollectionWithAbstract: CollectionSearchResult = new CollectionSearchResult();
-mockCollectionWithAbstract.hitHighlights = [];
+mockCollectionWithAbstract.hitHighlights = {};
 mockCollectionWithAbstract.dspaceObject = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    } ]
+      }
+    ]
+  }
 });

 const mockCollectionWithoutAbstract: CollectionSearchResult = new CollectionSearchResult();
-mockCollectionWithoutAbstract.hitHighlights = [];
+mockCollectionWithoutAbstract.hitHighlights = {};
 mockCollectionWithoutAbstract.dspaceObject = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    } ]
+      }
+    ]
+  }
 });

 describe('CollectionSearchResultGridElementComponent', () => {
--- a/src/app/shared/object-grid/search-result-grid-element/community-search-result/community-search-result-grid-element.component.spec.ts
+++ b/src/app/shared/object-grid/search-result-grid-element/community-search-result/community-search-result-grid-element.component.spec.ts
@@ -16,25 +16,29 @@ const truncatableServiceStub: any = {
 };

 const mockCommunityWithAbstract: CommunitySearchResult = new CommunitySearchResult();
-mockCommunityWithAbstract.hitHighlights = [];
+mockCommunityWithAbstract.hitHighlights = {};
 mockCommunityWithAbstract.dspaceObject = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    } ]
+      }
+    ]
+  }
 });

 const mockCommunityWithoutAbstract: CommunitySearchResult = new CommunitySearchResult();
-mockCommunityWithoutAbstract.hitHighlights = [];
+mockCommunityWithoutAbstract.hitHighlights = {};
 mockCommunityWithoutAbstract.dspaceObject = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    } ]
+      }
+    ]
+  }
 });

 describe('CommunitySearchResultGridElementComponent', () => {
--- a/src/app/shared/object-grid/search-result-grid-element/item-search-result/item-search-result-grid-element.component.html
+++ b/src/app/shared/object-grid/search-result-grid-element/item-search-result/item-search-result-grid-element.component.html
@@ -8,20 +8,20 @@
        </a>
        <div class="card-body">
            <ds-truncatable-part [fixedHeight]="true" [id]="dso.id" [minLines]="3" type="h4">
-                <h4 class="card-title" [innerHTML]="dso.findMetadata('dc.title')"></h4>
+                <h4 class="card-title" [innerHTML]="dso.firstMetadataValue('dc.title')"></h4>
            </ds-truncatable-part>
-            <p *ngIf="dso.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']).length > 0"
+            <p *ngIf="dso.hasMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])"
               class="item-authors card-text text-muted">
                <ds-truncatable-part [fixedHeight]="true" [id]="dso.id" [minLines]="1">
-                    <span *ngIf="hasValue(dso.findMetadata('dc.date.issued'))" class="item-date">{{dso.findMetadata("dc.date.issued")}}</span>
-                    <span *ngFor="let authorMd of dso.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']);">,
-                        <span [innerHTML]="authorMd.value"></span>
+                    <span *ngIf="dso.hasMetadata('dc.date.issued')" class="item-date">{{dso.firstMetadataValue('dc.date.issued')}}</span>
+                    <span *ngFor="let author of dso.allMetadataValues(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']);">,
+                        <span [innerHTML]="author"></span>
                    </span>
                </ds-truncatable-part>
            </p>
            <p class="item-abstract card-text">
                <ds-truncatable-part [fixedHeight]="true" [id]="dso.id" [minLines]="3">
-                    <span [innerHTML]="getFirstValue('dc.description.abstract')"></span>
+                    <span [innerHTML]="firstMetadataValue('dc.description.abstract')"></span>
                </ds-truncatable-part>
            </p>
            <div class="text-center">
--- a/src/app/shared/object-grid/search-result-grid-element/item-search-result/item-search-result-grid-element.component.spec.ts
+++ b/src/app/shared/object-grid/search-result-grid-element/item-search-result/item-search-result-grid-element.component.spec.ts
@@ -17,37 +17,43 @@ const truncatableServiceStub: any = {
 };

 const mockItemWithAuthorAndDate: ItemSearchResult = new ItemSearchResult();
-mockItemWithAuthorAndDate.hitHighlights = [];
+mockItemWithAuthorAndDate.hitHighlights = {};
 mockItemWithAuthorAndDate.dspaceObject = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.contributor.author': [
      {
-      key: 'dc.contributor.author',
        language: 'en_US',
        value: 'Smith, Donald'
-    },
+      }
+    ],
+    'dc.date.issued': [
      {
-      key: 'dc.date.issued',
        language: null,
        value: '2015-06-26'
-    }]
+      }
+    ]
+  }
 });

 const mockItemWithoutAuthorAndDate: ItemSearchResult = new ItemSearchResult();
-mockItemWithoutAuthorAndDate.hitHighlights = [];
+mockItemWithoutAuthorAndDate.hitHighlights = {};
 mockItemWithoutAuthorAndDate.dspaceObject = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'This is just another title'
-    },
+      }
+    ],
+    'dc.type': [
      {
-      key: 'dc.type',
        language: null,
        value: 'Article'
-    }]
+      }
+    ]
+  }
 });

 describe('ItemSearchResultGridElementComponent', () => {
--- a/src/app/shared/object-grid/search-result-grid-element/search-result-grid-element.component.ts
+++ b/src/app/shared/object-grid/search-result-grid-element/search-result-grid-element.component.ts
@@ -2,12 +2,11 @@ import { Component, Inject } from '@angular/core';

 import { SearchResult } from '../../../+search-page/search-result.model';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
-import { Metadatum } from '../../../core/shared/metadatum.model';
-import { isEmpty, hasNoValue, hasValue } from '../../empty.util';
 import { AbstractListableElementComponent } from '../../object-collection/shared/object-collection-element/abstract-listable-element.component';
 import { ListableObject } from '../../object-collection/shared/listable-object.model';
 import { TruncatableService } from '../../truncatable/truncatable.service';
 import { Observable } from 'rxjs';
+import { Metadata } from '../../../core/shared/metadata.model';

@Component({
  selector: 'ds-search-result-grid-element',
@@ -22,39 +21,24 @@ export class SearchResultGridElementComponent<T extends SearchResult<K>, K exten
    this.dso = this.object.dspaceObject;
  }

-  getValues(keys: string[]): string[] {
-    const results: string[] = new Array<string>();
-    this.object.hitHighlights.forEach(
-      (md: Metadatum) => {
-        if (keys.indexOf(md.key) > -1) {
-          results.push(md.value);
-        }
-      }
-    );
-    if (isEmpty(results)) {
-      this.dso.filterMetadata(keys).forEach(
-        (md: Metadatum) => {
-          results.push(md.value);
-        }
-      );
-    }
-    return results;
+  /**
+   * Gets all matching metadata string values from hitHighlights or dso metadata, preferring hitHighlights.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @returns {string[]} the matching string values or an empty array.
+   */
+  allMetadataValues(keyOrKeys: string | string[]): string[] {
+    return Metadata.allValues([this.object.hitHighlights, this.dso.metadata], keyOrKeys);
  }

-  getFirstValue(key: string): string {
-    let result: string;
-    this.object.hitHighlights.some(
-      (md: Metadatum) => {
-        if (key === md.key) {
-          result = md.value;
-          return true;
-        }
-      }
-    );
-    if (hasNoValue(result)) {
-      result = this.dso.findMetadata(key);
-    }
-    return result;
+  /**
+   * Gets the first matching metadata string value from hitHighlights or dso metadata, preferring hitHighlights.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @returns {string} the first matching string value, or `undefined`.
+   */
+  firstMetadataValue(keyOrKeys: string | string[]): string {
+    return Metadata.firstValue([this.object.hitHighlights, this.dso.metadata], keyOrKeys);
  }

  isCollapsed(): Observable<boolean> {
--- a/src/app/shared/object-list/browse-entry-list-element/browse-entry-list-element.component.spec.ts
+++ b/src/app/shared/object-list/browse-entry-list-element/browse-entry-list-element.component.spec.ts
@@ -2,7 +2,6 @@ import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { ChangeDetectionStrategy, NO_ERRORS_SCHEMA } from '@angular/core';
 import { By } from '@angular/platform-browser';
 import { TruncatePipe } from '../../utils/truncate.pipe';
-import { Metadatum } from '../../../core/shared/metadatum.model';
 import { BrowseEntryListElementComponent } from './browse-entry-list-element.component';
 import { BrowseEntry } from '../../../core/shared/browse-entry.model';

@@ -33,7 +32,7 @@ describe('MetadataListElementComponent', () => {
    browseEntryListElementComponent = fixture.componentInstance;
  }));

-  describe('When the metadatum is loaded', () => {
+  describe('When the metadata is loaded', () => {
    beforeEach(() => {
      browseEntryListElementComponent.object = mockValue;
      fixture.detectChanges();
--- a/src/app/shared/object-list/collection-list-element/collection-list-element.component.spec.ts
+++ b/src/app/shared/object-list/collection-list-element/collection-list-element.component.spec.ts
@@ -8,21 +8,25 @@ let collectionListElementComponent: CollectionListElementComponent;
 let fixture: ComponentFixture<CollectionListElementComponent>;

 const mockCollectionWithAbstract: Collection = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    }]
+      }
+    ]
+  }
 });

 const mockCollectionWithoutAbstract: Collection = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    }]
+      }
+    ]
+  }
 });

 describe('CollectionListElementComponent', () => {
--- a/src/app/shared/object-list/community-list-element/community-list-element.component.spec.ts
+++ b/src/app/shared/object-list/community-list-element/community-list-element.component.spec.ts
@@ -8,21 +8,25 @@ let communityListElementComponent: CommunityListElementComponent;
 let fixture: ComponentFixture<CommunityListElementComponent>;

 const mockCommunityWithAbstract: Community = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    }]
+      }
+    ]
+  }
 });

 const mockCommunityWithoutAbstract: Community = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    }]
+      }
+    ]
+  }
 });

 describe('CommunityListElementComponent', () => {
--- a/src/app/shared/object-list/item-list-element/item-list-element.component.html
+++ b/src/app/shared/object-list/item-list-element/item-list-element.component.html
@@ -1,23 +1,23 @@
 <ds-truncatable [id]="object.id">
  <a [routerLink]="['/items/' + object.id]" class="lead">
-      {{object.findMetadata("dc.title")}}
+    {{object.firstMetadataValue("dc.title")}}
  </a>
  <div>
    <ds-truncatable-part [id]="object.id" [minLines]="1">
      <span class="text-muted">
-        <span *ngIf="object.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']).length > 0"
+        <span *ngIf="object.hasMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])"
              class="item-list-authors">
-            <span *ngFor="let authorMd of object.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']); let last=last;">{{authorMd.value}}
+            <span *ngFor="let author of object.allMetadataValues(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']); let last=last;">{{author}}
                <span *ngIf="!last">; </span>
            </span>
        </span>
-        (<span *ngIf="hasValue(object.findMetadata('dc.publisher'))" class="item-list-publisher">{{object.findMetadata("dc.publisher")}}, </span><span
-              *ngIf="hasValue(object.findMetadata('dc.date.issued'))" class="item-list-date">{{object.findMetadata("dc.date.issued")}}</span>)
+        (<span *ngIf="object.hasMetadata('dc.publisher')" class="item-list-publisher">{{object.firstMetadataValue("dc.publisher")}}, </span><span
+        *ngIf="object.hasMetadata('dc.date.issued')" class="item-list-date">{{object.firstMetadataValue("dc.date.issued")}}</span>)
      </span>
    </ds-truncatable-part>
    <ds-truncatable-part [id]="object.id" [minLines]="3">
-      <div *ngIf="object.findMetadata('dc.description.abstract')" class="item-list-abstract">
-          {{object.findMetadata("dc.description.abstract")}}
+      <div *ngIf="object.hasMetadata('dc.description.abstract')" class="item-list-abstract">
+        {{object.firstMetadataValue("dc.description.abstract")}}
      </div>
    </ds-truncatable-part>
  </div>
--- a/src/app/shared/object-list/item-list-element/item-list-element.component.spec.ts
+++ b/src/app/shared/object-list/item-list-element/item-list-element.component.spec.ts
@@ -11,31 +11,37 @@ let fixture: ComponentFixture<ItemListElementComponent>;

 const mockItemWithAuthorAndDate: Item = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.contributor.author': [
      {
-      key: 'dc.contributor.author',
        language: 'en_US',
        value: 'Smith, Donald'
-    },
+      }
+    ],
+    'dc.date.issued': [
      {
-      key: 'dc.date.issued',
        language: null,
        value: '2015-06-26'
-    }]
+      }
+    ]
+  }
 });
 const mockItemWithoutAuthorAndDate: Item = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'This is just another title'
-    },
+      }
+    ],
+    'dc.type': [
      {
-      key: 'dc.type',
        language: null,
        value: 'Article'
-    }]
+      }
+    ]
+  }
 });

 describe('ItemListElementComponent', () => {
--- a/src/app/shared/object-list/search-result-list-element/collection-search-result/collection-search-result-list-element.component.html
+++ b/src/app/shared/object-list/search-result-list-element/collection-search-result/collection-search-result-list-element.component.html
@@ -1,2 +1,2 @@
-<a [routerLink]="['/collections/' + dso.id]" class="lead" [innerHTML]="getFirstValue('dc.title')"></a>
-<div *ngIf="dso.shortDescription" class="text-muted abstract-text" [innerHTML]="getFirstValue('dc.description.abstract')"></div>
+<a [routerLink]="['/collections/' + dso.id]" class="lead" [innerHTML]="firstMetadataValue('dc.title')"></a>
+<div *ngIf="dso.shortDescription" class="text-muted abstract-text" [innerHTML]="firstMetadataValue('dc.description.abstract')"></div>
--- a/src/app/shared/object-list/search-result-list-element/collection-search-result/collection-search-result-list-element.component.spec.ts
+++ b/src/app/shared/object-list/search-result-list-element/collection-search-result/collection-search-result-list-element.component.spec.ts
@@ -16,25 +16,29 @@ const truncatableServiceStub: any = {
 };

 const mockCollectionWithAbstract: CollectionSearchResult = new CollectionSearchResult();
-mockCollectionWithAbstract.hitHighlights = [];
+mockCollectionWithAbstract.hitHighlights = {};
 mockCollectionWithAbstract.dspaceObject = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    } ]
+      }
+    ]
+  }
 });

 const mockCollectionWithoutAbstract: CollectionSearchResult = new CollectionSearchResult();
-mockCollectionWithoutAbstract.hitHighlights = [];
+mockCollectionWithoutAbstract.hitHighlights = {};
 mockCollectionWithoutAbstract.dspaceObject = Object.assign(new Collection(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    } ]
+      }
+    ]
+  }
 });

 describe('CollectionSearchResultListElementComponent', () => {
--- a/src/app/shared/object-list/search-result-list-element/community-search-result/community-search-result-list-element.component.html
+++ b/src/app/shared/object-list/search-result-list-element/community-search-result/community-search-result-list-element.component.html
@@ -1,2 +1,2 @@
-<a [routerLink]="['/communities/' + dso.id]" class="lead" [innerHTML]="getFirstValue('dc.title')"></a>
-<div *ngIf="dso.shortDescription" class="text-muted abstract-text" [innerHTML]="getFirstValue('dc.description.abstract')"></div>
+<a [routerLink]="['/communities/' + dso.id]" class="lead" [innerHTML]="firstMetadataValue('dc.title')"></a>
+<div *ngIf="dso.shortDescription" class="text-muted abstract-text" [innerHTML]="firstMetadataValue('dc.description.abstract')"></div>
--- a/src/app/shared/object-list/search-result-list-element/community-search-result/community-search-result-list-element.component.spec.ts
+++ b/src/app/shared/object-list/search-result-list-element/community-search-result/community-search-result-list-element.component.spec.ts
@@ -16,25 +16,29 @@ const truncatableServiceStub: any = {
 };

 const mockCommunityWithAbstract: CommunitySearchResult = new CommunitySearchResult();
-mockCommunityWithAbstract.hitHighlights = [];
+mockCommunityWithAbstract.hitHighlights = {};
 mockCommunityWithAbstract.dspaceObject = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.description.abstract': [
      {
-      key: 'dc.description.abstract',
        language: 'en_US',
        value: 'Short description'
-    } ]
+      }
+    ]
+  }
 });

 const mockCommunityWithoutAbstract: CommunitySearchResult = new CommunitySearchResult();
-mockCommunityWithoutAbstract.hitHighlights = [];
+mockCommunityWithoutAbstract.hitHighlights = {};
 mockCommunityWithoutAbstract.dspaceObject = Object.assign(new Community(), {
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'Test title'
-    } ]
+      }
+    ]
+  }
 });

 describe('CommunitySearchResultListElementComponent', () => {
--- a/src/app/shared/object-list/search-result-list-element/item-search-result/item-search-result-list-element.component.html
+++ b/src/app/shared/object-list/search-result-list-element/item-search-result/item-search-result-list-element.component.html
@@ -1,24 +1,24 @@
 <ds-truncatable [id]="dso.id">
        <a
            [routerLink]="['/items/' + dso.id]" class="lead"
-            [innerHTML]="getFirstValue('dc.title')"></a>
+            [innerHTML]="firstMetadataValue('dc.title')"></a>
  <span class="text-muted">
    <ds-truncatable-part [id]="dso.id" [minLines]="1">
-            (<span *ngIf="dso.findMetadata('dc.publisher')" class="item-list-publisher"
-                   [innerHTML]="getFirstValue('dc.publisher') + ', '"></span><span
-            *ngIf="hasValue(dso.findMetadata('dc.date.issued'))" class="item-list-date"
-            [innerHTML]="getFirstValue('dc.date.issued')"></span>)
-            <span *ngIf="dso.filterMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']).length > 0"
+            (<span *ngIf="dso.hasMetadata('dc.publisher')" class="item-list-publisher"
+                   [innerHTML]="firstMetadataValue('dc.publisher') + ', '"></span><span
+      *ngIf="dso.hasMetadata('dc.date.issued')" class="item-list-date"
+      [innerHTML]="firstMetadataValue('dc.date.issued')"></span>)
+            <span *ngIf="dso.hasMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])"
                  class="item-list-authors">
-                    <span *ngFor="let author of getValues(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']); let last=last;">
+                    <span *ngFor="let author of allMetadataValues(['dc.contributor.author', 'dc.creator', 'dc.contributor.*']); let last=last;">
                        <span [innerHTML]="author"><span [innerHTML]="author"></span></span>
                    </span>
            </span>
        </ds-truncatable-part>
  </span>
-            <div *ngIf="dso.findMetadata('dc.description.abstract')" class="item-list-abstract">
+            <div *ngIf="dso.hasMetadata('dc.description.abstract')" class="item-list-abstract">
                <ds-truncatable-part [id]="dso.id" [minLines]="3"><span
-                        [innerHTML]="getFirstValue('dc.description.abstract')"></span>
+                        [innerHTML]="firstMetadataValue('dc.description.abstract')"></span>
                </ds-truncatable-part>
            </div>
 </ds-truncatable>
--- a/src/app/shared/object-list/search-result-list-element/item-search-result/item-search-result-list-element.component.spec.ts
+++ b/src/app/shared/object-list/search-result-list-element/item-search-result/item-search-result-list-element.component.spec.ts
@@ -17,37 +17,43 @@ const truncatableServiceStub: any = {
 };

 const mockItemWithAuthorAndDate: ItemSearchResult = new ItemSearchResult();
-mockItemWithAuthorAndDate.hitHighlights = [];
+mockItemWithAuthorAndDate.hitHighlights = {};
 mockItemWithAuthorAndDate.dspaceObject = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.contributor.author': [
      {
-      key: 'dc.contributor.author',
        language: 'en_US',
        value: 'Smith, Donald'
-    },
+      }
+    ],
+    'dc.date.issued': [
      {
-      key: 'dc.date.issued',
        language: null,
        value: '2015-06-26'
-    }]
+      }
+    ]
+  }
 });

 const mockItemWithoutAuthorAndDate: ItemSearchResult = new ItemSearchResult();
-mockItemWithoutAuthorAndDate.hitHighlights = [];
+mockItemWithoutAuthorAndDate.hitHighlights = {};
 mockItemWithoutAuthorAndDate.dspaceObject = Object.assign(new Item(), {
  bitstreams: observableOf({}),
-  metadata: [
+  metadata: {
+    'dc.title': [
      {
-      key: 'dc.title',
        language: 'en_US',
        value: 'This is just another title'
-    },
+      }
+    ],
+    'dc.type': [
      {
-      key: 'dc.type',
        language: null,
        value: 'Article'
-    }]
+      }
+    ]
+  }
 });

 describe('ItemSearchResultListElementComponent', () => {
--- a/src/app/shared/object-list/search-result-list-element/search-result-list-element.component.ts
+++ b/src/app/shared/object-list/search-result-list-element/search-result-list-element.component.ts
@@ -3,11 +3,10 @@ import { Observable } from 'rxjs';

 import { SearchResult } from '../../../+search-page/search-result.model';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
-import { Metadatum } from '../../../core/shared/metadatum.model';
-import { hasNoValue, isEmpty } from '../../empty.util';
 import { ListableObject } from '../../object-collection/shared/listable-object.model';
 import { AbstractListableElementComponent } from '../../object-collection/shared/object-collection-element/abstract-listable-element.component';
 import { TruncatableService } from '../../truncatable/truncatable.service';
+import { Metadata } from '../../../core/shared/metadata.model';

@Component({
  selector: 'ds-search-result-list-element',
@@ -22,39 +21,24 @@ export class SearchResultListElementComponent<T extends SearchResult<K>, K exten
    this.dso = this.object.dspaceObject;
  }

-  getValues(keys: string[]): string[] {
-    const results: string[] = new Array<string>();
-    this.object.hitHighlights.forEach(
-      (md: Metadatum) => {
-        if (keys.indexOf(md.key) > -1) {
-          results.push(md.value);
-        }
-      }
-    );
-    if (isEmpty(results)) {
-      this.dso.filterMetadata(keys).forEach(
-        (md: Metadatum) => {
-          results.push(md.value);
-        }
-      );
-    }
-    return results;
+  /**
+   * Gets all matching metadata string values from hitHighlights or dso metadata, preferring hitHighlights.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @returns {string[]} the matching string values or an empty array.
+   */
+  allMetadataValues(keyOrKeys: string | string[]): string[] {
+    return Metadata.allValues([this.object.hitHighlights, this.dso.metadata], keyOrKeys);
  }

-  getFirstValue(key: string): string {
-    let result: string;
-    this.object.hitHighlights.some(
-      (md: Metadatum) => {
-        if (key === md.key) {
-          result = md.value;
-          return true;
-        }
-      }
-    );
-    if (hasNoValue(result)) {
-      result = this.dso.findMetadata(key);
-    }
-    return result;
+  /**
+   * Gets the first matching metadata string value from hitHighlights or dso metadata, preferring hitHighlights.
+   *
+   * @param {string|string[]} keyOrKeys The metadata key(s) in scope. Wildcards are supported; see [[Metadata]].
+   * @returns {string} the first matching string value, or `undefined`.
+   */
+  firstMetadataValue(keyOrKeys: string | string[]): string {
+    return Metadata.firstValue([this.object.hitHighlights, this.dso.metadata], keyOrKeys);
  }

  isCollapsed(): Observable<boolean> {
--- a/src/app/shared/search-form/search-form.component.spec.ts
+++ b/src/app/shared/search-form/search-form.component.spec.ts
@@ -30,6 +30,7 @@ describe('SearchFormComponent', () => {
  });

  it('should display scopes when available with default and all scopes', () => {
+
    comp.scopes = objects;
    fixture.detectChanges();
    const select: HTMLElement = de.query(By.css('select')).nativeElement;
@@ -121,33 +122,38 @@ export const objects: DSpaceObject[] = [
    id: '7669c72a-3f2a-451f-a3b9-9210e7a4c02f',
    uuid: '7669c72a-3f2a-451f-a3b9-9210e7a4c02f',
    type: ResourceType.Community,
-    metadata: [
+    metadata: {
+      'dc.description': [
        {
-        key: 'dc.description',
          language: null,
          value: ''
-      },
+        }
+      ],
+      'dc.description.abstract': [
        {
-        key: 'dc.description.abstract',
          language: null,
          value: 'This is a test community to hold content for the OR2017 demostration'
-      },
+        }
+      ],
+      'dc.description.tableofcontents': [
        {
-        key: 'dc.description.tableofcontents',
          language: null,
          value: ''
-      },
+        }
+      ],
+      'dc.rights': [
        {
-        key: 'dc.rights',
          language: null,
          value: ''
-      },
+        }
+      ],
+      'dc.title': [
        {
-        key: 'dc.title',
          language: null,
          value: 'OR2017 - Demonstration'
        }
      ]
+    }
  }),
  Object.assign(new Community(),
    {
@@ -170,33 +176,38 @@ export const objects: DSpaceObject[] = [
      id: '9076bd16-e69a-48d6-9e41-0238cb40d863',
      uuid: '9076bd16-e69a-48d6-9e41-0238cb40d863',
      type: ResourceType.Community,
-      metadata: [
+      metadata: {
+        'dc.description': [
          {
-          key: 'dc.description',
            language: null,
            value: '<p>This is the introductory text for the <em>Sample Community</em> on the DSpace Demonstration Site. It is editable by System or Community Administrators (of this Community).</p>\r\n<p><strong>DSpace Communities may contain one or more Sub-Communities or Collections (of Items).</strong></p>\r\n<p>This particular Community has its own logo (the <a href=\'http://www.duraspace.org/\'>DuraSpace</a> logo).</p>'
-        },
+          }
+        ],
+        'dc.description.abstract': [
          {
-          key: 'dc.description.abstract',
            language: null,
            value: 'This is a sample top-level community'
-        },
+          }
+        ],
+        'dc.description.tableofcontents': [
          {
-          key: 'dc.description.tableofcontents',
            language: null,
            value: '<p>This is the <em>news section</em> for this <em>Sample Community</em>. System or Community Administrators (of this Community) can edit this News field.</p>'
-        },
+          }
+        ],
+        'dc.rights': [
          {
-          key: 'dc.rights',
            language: null,
            value: '<p><em>If this Community had special copyright text to display, it would be displayed here.</em></p>'
-        },
+          }
+        ],
+        'dc.title': [
          {
-          key: 'dc.title',
            language: null,
            value: 'Sample Community'
          }
        ]
      }
+    }
  )
 ];