[1270] Change explorer to link representation behavior to ViewUsage

CHANGELOG.adoc

@@ -6,6 +6,10 @@
 
 - Add support for `ViewUsages` and `ViewDefinitions`
 
+=== Architectural decision records
+
+- Support representation only through `ViewUsage`
+
 === Breaking changes
 
 === Dependency update
@@ -35,6 +39,9 @@ When end-users click on _New Object_ on a semantic element, and select a `ViewUs
 === New features
 
 - https://github.com/eclipse-syson/syson/issues/1237[#1237] [general-view] Add `ViewUsage` graphical node in the General View diagram.
+- https://github.com/eclipse-syson/syson/issues/1270[#1270] [explorer-view] Change explorer to link representation behavior to `ViewUsage`:
+* Open associated representation when a `ViewUsage` is selected
+* Hide representation in the explorer
 
 == v2025.4.0
 

backend/views/syson-tree-explorer-view/src/main/java/org/eclipse/syson/tree/explorer/view/SysONExplorerTreeDescriptionProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2025 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -67,7 +67,7 @@ private TreeDescription build() {
                 .preconditionExpression("aql:false")
                 .selectableExpression("aql:self.isSelectable()")
                 .titleExpression(SYSON_EXPLORER)
-                .treeItemIdExpression("aql:self.getTreeItemId()")
+                .treeItemIdExpression("aql:self.getTreeItemId(editingContext)")
                 .treeItemObjectExpression("aql:id.getTreeItemObject(editingContext)")
                 .treeItemLabelDescriptions(this.createDefaultStyle())
                 .build();

backend/views/syson-tree-explorer-view/src/main/java/org/eclipse/syson/tree/explorer/view/services/ComposedSysONExplorerService.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2025 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -42,10 +42,10 @@ public ComposedSysONExplorerService(List<ISysONExplorerServiceDelegate> explorer
     }
 
     @Override
-    public String getTreeItemId(Object self) {
+    public String getTreeItemId(Object self, IEditingContext editingContext) {
         return this.getDelegate(self)
                 .map(delegate -> delegate.getTreeItemId(self))
-                .orElseGet(() -> this.defaultExplorerService.getTreeItemId(self));
+                .orElseGet(() -> this.defaultExplorerService.getTreeItemId(self, editingContext));
     }
 
     @Override

backend/views/syson-tree-explorer-view/src/main/java/org/eclipse/syson/tree/explorer/view/services/SysONDefaultExplorerServices.java

@@ -15,21 +15,25 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.UUID;
 
 import org.eclipse.emf.ecore.EAnnotation;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.sirius.components.core.api.IContentService;
 import org.eclipse.sirius.components.core.api.IEditingContext;
 import org.eclipse.sirius.components.core.api.IIdentityService;
+import org.eclipse.sirius.components.core.api.IObjectService;
 import org.eclipse.sirius.web.application.UUIDParser;
 import org.eclipse.sirius.web.application.editingcontext.EditingContext;
 import org.eclipse.sirius.web.application.views.explorer.services.api.IExplorerServices;
+import org.eclipse.sirius.web.domain.boundedcontexts.representationdata.RepresentationMetadata;
 import org.eclipse.sirius.web.domain.boundedcontexts.representationdata.services.api.IRepresentationMetadataSearchService;
 import org.eclipse.syson.services.UtilService;
 import org.eclipse.syson.services.api.ISysONResourceService;
 import org.eclipse.syson.sysml.Element;
 import org.eclipse.syson.sysml.Namespace;
+import org.eclipse.syson.sysml.ViewUsage;
 import org.eclipse.syson.sysml.util.ElementUtil;
 import org.eclipse.syson.tree.explorer.view.fragments.LibrariesDirectory;
 import org.eclipse.syson.tree.explorer.view.services.api.ISysONDefaultExplorerService;
@@ -57,17 +61,20 @@ public class SysONDefaultExplorerServices implements ISysONDefaultExplorerServic
     private final ISysONExplorerFilterService filterService;
 
     private final UtilService utilService = new UtilService();
-    
+
     private final ISysONResourceService sysONResourceService;
 
+    private final IObjectService objectService;
+
     public SysONDefaultExplorerServices(IIdentityService identityService, IContentService contentService, IRepresentationMetadataSearchService representationMetadataSearchService, IExplorerServices explorerServices,
-            ISysONExplorerFilterService filterService, final ISysONResourceService sysONResourceService) {
+            ISysONExplorerFilterService filterService, final ISysONResourceService sysONResourceService, IObjectService objectService) {
         this.identityService = Objects.requireNonNull(identityService);
         this.contentService = Objects.requireNonNull(contentService);
         this.representationMetadataSearchService = Objects.requireNonNull(representationMetadataSearchService);
         this.explorerServices = Objects.requireNonNull(explorerServices);
         this.filterService = Objects.requireNonNull(filterService);
         this.sysONResourceService = Objects.requireNonNull(sysONResourceService);
+        this.objectService = Objects.requireNonNull(objectService);
     }
 
     @Override
@@ -89,10 +96,22 @@ public List<Object> getElements(IEditingContext editingContext, List<String> act
     }
 
     @Override
-    public String getTreeItemId(Object self) {
+    public String getTreeItemId(Object self, IEditingContext editingContext) {
         String id = null;
         if (self instanceof ISysONExplorerFragment fragment) {
             id = fragment.getId();
+        } else if (self instanceof ViewUsage viewUsage) {
+            var optionalSemanticDataId = new UUIDParser().parse(editingContext.getId());
+            if (optionalSemanticDataId.isPresent()) {
+                String viewUsageId = this.identityService.getId(viewUsage);
+                id = this.representationMetadataSearchService.findAllRepresentationMetadataBySemanticDataAndTargetObjectId(AggregateReference.to(optionalSemanticDataId.get()), viewUsageId)
+                        .stream()
+                        .map(RepresentationMetadata::getId)
+                        .filter(Objects::nonNull)
+                        .map(UUID::toString)
+                        .findAny()
+                        .orElse(viewUsageId);
+            }
         } else {
             id = this.explorerServices.getTreeItemId(self);
         }
@@ -135,33 +154,27 @@ public boolean hasChildren(Object self, IEditingContext editingContext, List<Str
             hasChildren = !this.filterService.applyFilters(resource.getContents(), activeFilterIds).isEmpty();
         } else if (self instanceof Element element) {
             List<Object> contents = this.filterService.applyFilters(this.contentService.getContents(self), activeFilterIds);
-            hasChildren = !contents.isEmpty() && contents.stream().anyMatch(e -> !(e instanceof EAnnotation))
-                || this.hasRepresentation(element, editingContext);
-        } else {
-            hasChildren = explorerServices.hasChildren(self, editingContext);
+            hasChildren = !contents.isEmpty() && contents.stream().anyMatch(e -> !(e instanceof EAnnotation));
+        } else if (self instanceof EObject eObject) {
+            hasChildren = !eObject.eContents().isEmpty();
         }
         return hasChildren;
     }
 
-    private boolean hasRepresentation(EObject self, IEditingContext editingContext) {
-        var optionalSemanticDataId = new UUIDParser().parse(editingContext.getId());
-        if (optionalSemanticDataId.isPresent()) {
-            String id = this.identityService.getId(self);
-            return this.representationMetadataSearchService.existAnyRepresentationMetadataForSemanticDataAndTargetObjectId(AggregateReference.to(optionalSemanticDataId.get()), id);
-        }
-        return false;
-    }
-
     @Override
     public List<Object> getChildren(Object self, IEditingContext editingContext, List<String> expandedIds, List<String> activeFilterIds) {
         List<Object> result = new ArrayList<>();
-        String id = this.getTreeItemId(self);
+        String id = this.getTreeItemId(self, editingContext);
         if (self instanceof ISysONExplorerFragment fragment) {
             if (expandedIds.contains(id)) {
                 result.addAll(fragment.getChildren(editingContext, expandedIds, activeFilterIds));
             }
+        } else if (self instanceof ViewUsage) {
+            if (expandedIds.contains(id)) {
+                result.addAll(this.objectService.getContents(self));
+            }
         } else {
-            result.addAll(this.explorerServices.getDefaultChildren(self, editingContext, expandedIds));
+            result.addAll(this.explorerServices.getDefaultChildren(self, editingContext, expandedIds).stream().filter(child -> !(child instanceof RepresentationMetadata)).toList());
         }
 
         result = this.filterService.applyFilters(result, activeFilterIds);
@@ -201,10 +214,10 @@ public boolean isEditable(Object self) {
         } else if (self instanceof Resource resource) {
             result = !(this.filterService.isUserLibrary(resource))
                     && resource.getContents().stream()
-                            .filter(Namespace.class::isInstance)
-                            .map(Namespace.class::cast)
-                            .flatMap(namespace -> namespace.getOwnedElement().stream())
-                            .noneMatch(ElementUtil::isFromStandardLibrary);
+                    .filter(Namespace.class::isInstance)
+                    .map(Namespace.class::cast)
+                    .flatMap(namespace -> namespace.getOwnedElement().stream())
+                    .noneMatch(ElementUtil::isFromStandardLibrary);
         }
         return result;
     }

backend/views/syson-tree-explorer-view/src/main/java/org/eclipse/syson/tree/explorer/view/services/api/ISysONDefaultExplorerService.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2025 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -23,7 +23,7 @@
  */
 public interface ISysONDefaultExplorerService {
 
-    String getTreeItemId(Object self);
+    String getTreeItemId(Object self, IEditingContext editingContext);
 
     String getKind(Object self);
 

backend/views/syson-tree-explorer-view/src/main/java/org/eclipse/syson/tree/explorer/view/services/api/ISysONExplorerService.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2025 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -23,7 +23,7 @@
  */
 public interface ISysONExplorerService {
 
-    String getTreeItemId(Object self);
+    String getTreeItemId(Object self, IEditingContext editingContext);
 
     String getKind(Object self);
 

backend/views/syson-tree-explorer-view/src/test/java/org/eclipse/syson/tree/explorer/view/services/SysONDefaultExplorerServicesTest.java

@@ -56,16 +56,14 @@
 
 /**
  * Tests the {@link SysONExplorerFilterService} class.
- * 
+ *
  * @author dvojtise
  */
 public class SysONDefaultExplorerServicesTest {
 
+    private final ISysONResourceService sysONResourceService = new SysONResourceService();
     private static EditingContext editingContext;
-
     private SysONDefaultExplorerServices sysONDefaultExplorerServices;
-
-    private final ISysONResourceService sysONResourceService = new SysONResourceService();
 
     @BeforeAll
     static void createEditingContext() {
@@ -99,9 +97,9 @@ public void hasChildrenCanHandleNonSysmlContent() {
         EAttribute c1a2 = EcoreFactory.eINSTANCE.createEAttribute();
         c1.getEStructuralFeatures().add(c1a2);
 
-        assertThat(sysONDefaultExplorerServices.hasChildren(ePackage, editingContext, List.of(), List.of())).isTrue();
-        assertThat(sysONDefaultExplorerServices.hasChildren(c1, editingContext, List.of(), List.of())).isTrue();
-        assertThat(sysONDefaultExplorerServices.hasChildren(c1a1, editingContext, List.of(), List.of())).isFalse();
+        assertThat(this.sysONDefaultExplorerServices.hasChildren(ePackage, editingContext, List.of(), List.of())).isTrue();
+        assertThat(this.sysONDefaultExplorerServices.hasChildren(c1, editingContext, List.of(), List.of())).isTrue();
+        assertThat(this.sysONDefaultExplorerServices.hasChildren(c1a1, editingContext, List.of(), List.of())).isFalse();
     }
 
     /**
@@ -163,7 +161,8 @@ public boolean test(Object arg0) {
 
         ISysONExplorerFilterService filterService = new SysONExplorerFilterService(this.sysONResourceService);
 
-        sysONDefaultExplorerServices = new SysONDefaultExplorerServices(identityService, contentService, representationMetadataSearchService, explorerServices, filterService, this.sysONResourceService);
+        this.sysONDefaultExplorerServices = new SysONDefaultExplorerServices(identityService, contentService, representationMetadataSearchService, explorerServices, filterService,
+                this.sysONResourceService, new IObjectService.NoOp());
     }
 
 }

doc/adrs/002_support_representation_only_on_viewusage.Adoc

@@ -0,0 +1,25 @@
+= ADR-002 - Support representation only through ViewUsage
+
+== Context
+
+In the SysMLv2 specification, the `ViewDefinition` concept allows defining how to render elements (textual, graphical...) and `ViewUsage` is an instance of a `ViewDefinition`.
+
+== Decision
+
+* Explorer in SysON should not provide representation anymore.
+Change the behavior of the Sysml custom explorer defined in `SysONExplorerTreeDescriptionProvider` to filter representation from children.
+
+* `ViewUsage` should open child representation.
+A `ViewUsage` can only manage exactly one representation.
+
+NOTE: The limitation of a single representation per `ViewUsage` should be ensured by the representation creation mechanism that automatically creates a `ViewUsage` as parent.
+In the same way, the creation of a `ViewUsage` must automatically create a representation as its child.
+
+To open a representation, the `selection` must be set to the representation id.
+Change the behavior in `SysONExplorerTreeDescriptionProvider` to return by the `treeItemIdExpression` the representation id for `ViewUsage` elements.
+The problem with changing only the `treeId` so that it points to the representation id instead of the semantic object id is that all other mechanisms (like the tree's
+`getChildren` or `dropElementFromExplorer`, for example) no longer work.
+All these mechanisms need to be customized to manage `ViewUsage`.
+
+NOTE: When selecting a `ViewUsage`, the detail views only display properties from the representation.
+

doc/content/modules/user-manual/pages/release-notes/2025.6.0.adoc

@@ -30,6 +30,10 @@ Publishing a project with a dependency to a library now correctly produces a lib
 
 image::view-usage-nodes.png[ViewUsage nodes, width=65%,height=65%]
 
+- Diagram representations like _General View_ are no longer directly available in the tree explorer.
+They are now managed through dedicated `ViewUsage` element.
+To open a diagram, you should now select the `ViewUsage` in the explorer.
+
 
 == Improvements