[2179] Improve selection dialog tree contents

CHANGELOG.adoc

@@ -88,6 +88,7 @@ Also use that same tool in the `interconnection` compartment.
 - https://github.com/eclipse-syson/syson/issues/2172[#2172] [diagrams] Add keybinding to the _Duplicate Element_ tool (ctrl+d).
 - https://github.com/eclipse-syson/syson/issues/2166[#2166] [diagrams] Reorganize tools to create `ExhibitStateUsage` graphical nodes, to ends up with two tools, one for parallel, one for non-parallel.
 Both tools optionally allow selecting an existing `StateUsage` to exhibit.
+- https://github.com/eclipse-syson/syson/issues/2179[#2179] [diagrams] Improve selection dialog by regrouping all standard libraries candidates under a "Libraries" category.
 
 === New features
 

backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/diagrams/general/view/GVTopNodeCreationTests.java

@@ -48,6 +48,7 @@
 import org.eclipse.sirius.components.graphql.tests.ExecuteEditingContextFunctionRunner;
 import org.eclipse.sirius.components.graphql.tests.ExecuteEditingContextFunctionSuccessPayload;
 import org.eclipse.sirius.components.trees.Tree;
+import org.eclipse.sirius.components.trees.TreeItem;
 import org.eclipse.sirius.components.view.diagram.NodeTool;
 import org.eclipse.sirius.components.view.diagram.SelectionDialogDescription;
 import org.eclipse.sirius.components.view.emf.diagram.IDiagramIdProvider;
@@ -73,6 +74,7 @@
 import org.eclipse.syson.sysml.LibraryPackage;
 import org.eclipse.syson.sysml.Namespace;
 import org.eclipse.syson.sysml.SysmlPackage;
+import org.eclipse.syson.tree.explorer.fragments.LibrariesDirectory;
 import org.eclipse.syson.util.IDescriptionNameGenerator;
 import org.eclipse.syson.util.SysONRepresentationDescriptionIdentifiers;
 import org.eclipse.syson.util.ViewConstants;
@@ -98,6 +100,10 @@
 @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
 public class GVTopNodeCreationTests extends AbstractIntegrationTests {
 
+    private static final String KERML_SELECTION_DIALOG_ID = UUID.nameUUIDFromBytes("SysON_KerML_Directory".getBytes()).toString();
+
+    private static final String SYSML_SELECTION_DIALOG_ID = UUID.nameUUIDFromBytes("SysON_SysML_Directory".getBytes()).toString();
+
     private final IDescriptionNameGenerator descriptionNameGenerator = new SDVDescriptionNameGenerator();
 
     @Autowired
@@ -358,12 +364,62 @@ public void givenAnEmptySysMLProjectWhenWeSubscribeToTheSelectionDialogTreeOfThe
             var input = new SelectionDialogTreeEventInput(UUID.randomUUID(), GeneralViewEmptyTestProjectData.EDITING_CONTEXT, representationId);
             var treeFlux = this.selectionDialogTreeEventSubscriptionRunner.run(input).flux();
 
-            var hasResourceRootContent = this.getTreeSubscriptionConsumer(tree -> {
-                // 95 is the number of standard libraries
-                assertThat(tree.getChildren()).isNotEmpty().hasSize(95);
+            var hasSelectionDialogRootContent = this.getTreeSubscriptionConsumer(tree -> {
+                assertThat(tree.getChildren()).isNotEmpty();
+
+                TreeItem librariesItem = tree.getChildren().stream()
+                        .filter(treeItem -> LibrariesDirectory.LIBRARIES_DIRECTORY_ID.equals(treeItem.getId()))
+                        .findFirst()
+                        .orElseThrow();
+                assertThat(librariesItem.getLabel().toString()).isEqualTo("Libraries");
+                assertThat(librariesItem.isEditable()).isFalse();
+                assertThat(librariesItem.isDeletable()).isFalse();
+                assertThat(librariesItem.isSelectable()).isFalse();
+                assertThat(librariesItem.isHasChildren()).isTrue();
+
+                assertThat(tree.getChildren()).anySatisfy(treeItem -> {
+                    assertThat(treeItem.getId()).isEqualTo(LibrariesDirectory.LIBRARIES_DIRECTORY_ID);
+                    assertThat(treeItem.getLabel().toString()).isEqualTo("Libraries");
+                });
             });
+
+            var expandedRepresentationId = this.representationIdBuilder.buildSelectionRepresentationId(selectionDialogDescriptionId.get().get(), GeneralViewEmptyTestProjectData.EDITING_CONTEXT,
+                    List.of(LibrariesDirectory.LIBRARIES_DIRECTORY_ID));
+            var expandedInput = new SelectionDialogTreeEventInput(UUID.randomUUID(), GeneralViewEmptyTestProjectData.EDITING_CONTEXT, expandedRepresentationId);
+            var expandedTreeFlux = this.selectionDialogTreeEventSubscriptionRunner.run(expandedInput).flux();
+
+            var hasExpandedLibrariesContent = this.getTreeSubscriptionConsumer(tree -> {
+                TreeItem librariesItem = tree.getChildren().stream()
+                        .filter(treeItem -> LibrariesDirectory.LIBRARIES_DIRECTORY_ID.equals(treeItem.getId()))
+                        .findFirst()
+                        .orElseThrow();
+
+                assertThat(librariesItem.getChildren()).hasSize(2);
+                assertThat(librariesItem.getChildren()).anySatisfy(treeItem -> {
+                    assertThat(treeItem.getId()).isEqualTo(KERML_SELECTION_DIALOG_ID);
+                    assertThat(treeItem.getLabel().toString()).isEqualTo("KerML");
+                    assertThat(treeItem.isEditable()).isFalse();
+                    assertThat(treeItem.isDeletable()).isFalse();
+                    assertThat(treeItem.isSelectable()).isFalse();
+                    assertThat(treeItem.isHasChildren()).isTrue();
+                });
+                assertThat(librariesItem.getChildren()).anySatisfy(treeItem -> {
+                    assertThat(treeItem.getId()).isEqualTo(SYSML_SELECTION_DIALOG_ID);
+                    assertThat(treeItem.getLabel().toString()).isEqualTo("SysML");
+                    assertThat(treeItem.isEditable()).isFalse();
+                    assertThat(treeItem.isDeletable()).isFalse();
+                    assertThat(treeItem.isSelectable()).isFalse();
+                    assertThat(treeItem.isHasChildren()).isTrue();
+                });
+            });
+
             StepVerifier.create(treeFlux)
-                    .consumeNextWith(hasResourceRootContent)
+                    .consumeNextWith(hasSelectionDialogRootContent)
+                    .thenCancel()
+                    .verify(Duration.ofSeconds(10));
+
+            StepVerifier.create(expandedTreeFlux)
+                    .consumeNextWith(hasExpandedLibrariesContent)
                     .thenCancel()
                     .verify(Duration.ofSeconds(10));
         }

backend/services/syson-diagram-services/src/main/java/org/eclipse/syson/diagram/services/DiagramQueryExposeService.java

@@ -17,10 +17,8 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Stream;
 
 import org.eclipse.emf.ecore.EClass;
-import org.eclipse.emf.ecore.EObject;
 import org.eclipse.sirius.components.collaborative.diagrams.DiagramContext;
 import org.eclipse.sirius.components.core.api.IEditingContext;
 import org.eclipse.syson.diagram.services.utils.ViewFilterSwitch;
@@ -130,16 +128,7 @@ public List<ReferenceUsage> getExposedSubjects(Element element, EClass domainTyp
                 .toList();
     }
 
-    public List<Element> getAllReachableRequirements(EObject eObject) {
-        List<EObject> allRequirementUsages = this.utilService.getAllReachableType(eObject, SysmlPackage.eINSTANCE.getRequirementUsage(), false);
-        List<EObject> allRequirementDefinitions = this.utilService.getAllReachableType(eObject, SysmlPackage.eINSTANCE.getRequirementDefinition(), false);
-        return Stream.concat(allRequirementUsages.stream(), allRequirementDefinitions.stream())
-                .filter(Element.class::isInstance)
-                .map(Element.class::cast)
-                .toList();
-    }
-
-    Set<Element> getDirectExposedElements(ViewUsage viewUsage) {
+    private Set<Element> getDirectExposedElements(ViewUsage viewUsage) {
         var directExposedElements = new HashSet<Element>();
         List<Expose> exposedElements = viewUsage.getOwnedRelationship().stream()
                 .filter(Expose.class::isInstance)

backend/services/syson-diagram-services/src/main/java/org/eclipse/syson/diagram/services/aql/DiagramQueryAQLService.java

@@ -16,7 +16,6 @@
 import java.util.Objects;
 
 import org.eclipse.emf.ecore.EClass;
-import org.eclipse.emf.ecore.EObject;
 import org.eclipse.sirius.components.collaborative.diagrams.DiagramContext;
 import org.eclipse.sirius.components.core.api.IEditingContext;
 import org.eclipse.sirius.components.diagrams.Diagram;
@@ -79,13 +78,6 @@ public boolean canCreateFlowUsage(ConnectionUsage connection) {
         return this.diagramQueryElementService.canCreateFlowUsage(connection);
     }
 
-    /**
-     * {@link DiagramQueryExposeService#getAllReachableRequirements(EObject)}.
-     */
-    public List<Element> getAllReachableRequirements(EObject eObject) {
-        return this.diagramQueryExposeService.getAllReachableRequirements(eObject);
-    }
-
     /**
      * {@link DiagramQueryLabelService#getBorderNodeUsageLabel(Usage)}.
      */

backend/services/syson-tree-services/src/main/java/org/eclipse/syson/tree/selectiondialog/services/SysONSelectionDialogFragmentIdentityService.java

@@ -0,0 +1,50 @@
+/*******************************************************************************
+ * Copyright (c) 2026 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
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.tree.selectiondialog.services;
+
+import org.eclipse.sirius.components.core.api.IIdentityServiceDelegate;
+import org.eclipse.syson.tree.explorer.services.api.ISysONExplorerFragment;
+import org.springframework.stereotype.Service;
+
+/**
+ * Identity service for SelectionDialog, to handle ISysONExplorerFragment elements.
+ *
+ * @author arichard
+ */
+@Service
+public class SysONSelectionDialogFragmentIdentityService implements IIdentityServiceDelegate {
+
+    @Override
+    public boolean canHandle(Object object) {
+        return object instanceof ISysONExplorerFragment;
+    }
+
+    @Override
+    public String getId(Object object) {
+        String id = null;
+        if (object instanceof ISysONExplorerFragment fragment) {
+            id = fragment.getId();
+        }
+        return id;
+    }
+
+    @Override
+    public String getKind(Object object) {
+        String kind = null;
+        if (object instanceof ISysONExplorerFragment fragment) {
+            kind = fragment.getKind();
+        }
+        return kind;
+    }
+
+}

backend/services/syson-tree-services/src/main/java/org/eclipse/syson/tree/selectiondialog/services/SysONSelectionDialogFragmentLabelService.java

@@ -0,0 +1,54 @@
+/*******************************************************************************
+ * Copyright (c) 2026 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
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.tree.selectiondialog.services;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.sirius.components.core.api.ILabelServiceDelegate;
+import org.eclipse.sirius.components.core.api.labels.StyledString;
+import org.eclipse.syson.tree.explorer.services.api.ISysONExplorerFragment;
+import org.springframework.stereotype.Service;
+
+/**
+ * Label service for SelectionDialog, to handle ISysONExplorerFragment elements.
+ *
+ * @author arichard
+ */
+@Service
+public class SysONSelectionDialogFragmentLabelService implements ILabelServiceDelegate {
+
+    @Override
+    public boolean canHandle(Object object) {
+        return object instanceof ISysONExplorerFragment;
+    }
+
+    @Override
+    public StyledString getStyledLabel(Object object) {
+        String label = "";
+        if (object instanceof ISysONExplorerFragment fragment) {
+            label = fragment.getLabel();
+        }
+        return StyledString.of(label);
+    }
+
+    @Override
+    public List<String> getImagePaths(Object object) {
+        List<String> imagePaths = new ArrayList<>();
+        if (object instanceof ISysONExplorerFragment fragment) {
+            imagePaths = fragment.getIconURL();
+        }
+        return imagePaths;
+    }
+
+}

backend/services/syson-tree-services/src/test/java/org/eclipse/syson/tree/explorer/services/SysONSelectionDialogFragmentServicesTest.java

@@ -0,0 +1,140 @@
+/*******************************************************************************
+ * Copyright (c) 2026 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
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.tree.explorer.services;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.List;
+
+import org.eclipse.sirius.components.core.api.IEditingContext;
+import org.eclipse.sirius.web.domain.boundedcontexts.representationdata.RepresentationMetadata;
+import org.eclipse.syson.tree.explorer.services.api.ISysONExplorerFragment;
+import org.eclipse.syson.tree.selectiondialog.services.SysONSelectionDialogFragmentIdentityService;
+import org.eclipse.syson.tree.selectiondialog.services.SysONSelectionDialogFragmentLabelService;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for selection dialog services handling {@link ISysONExplorerFragment}.
+ *
+ * @author arichard
+ */
+@SuppressWarnings("checkstyle:MultipleStringLiterals")
+public class SysONSelectionDialogFragmentServicesTest {
+
+    @Test
+    @DisplayName("GIVEN a selection dialog fragment identity service, WHEN the input is a fragment or not, THEN ids and kinds are resolved with the expected fallback")
+    public void identityServiceHandlesFragmentsAndFallsBackForOtherObjects() {
+        var service = new SysONSelectionDialogFragmentIdentityService();
+        var fragment = new TestFragment("fragment-id", "fragment-kind", "Fragment", List.of("icons/LibraryResource.svg"));
+
+        assertThat(service.canHandle(fragment)).isTrue();
+        assertThat(service.canHandle("not-a-fragment")).isFalse();
+        assertThat(service.getId(fragment)).isEqualTo("fragment-id");
+        assertThat(service.getKind(fragment)).isEqualTo("fragment-kind");
+        assertThat(service.getId("not-a-fragment")).isNull();
+        assertThat(service.getKind("not-a-fragment")).isNull();
+    }
+
+    @Test
+    @DisplayName("GIVEN a selection dialog fragment label service, WHEN the input is a fragment or not, THEN labels and icons are resolved with the expected fallback")
+    public void labelServiceHandlesFragmentsAndFallsBackForOtherObjects() {
+        var service = new SysONSelectionDialogFragmentLabelService();
+        var fragment = new TestFragment("fragment-id", "fragment-kind", "Fragment", List.of("icons/LibraryResource.svg"));
+
+        assertThat(service.canHandle(fragment)).isTrue();
+        assertThat(service.canHandle("not-a-fragment")).isFalse();
+        assertThat(service.getStyledLabel(fragment).toString()).isEqualTo("Fragment");
+        assertThat(service.getImagePaths(fragment)).containsExactly("icons/LibraryResource.svg");
+        assertThat(service.getStyledLabel("not-a-fragment").toString()).isEmpty();
+        assertThat(service.getImagePaths("not-a-fragment")).isEmpty();
+    }
+
+    /**
+     * Simple {@link ISysONExplorerFragment} stub used to exercise selection dialog delegates.
+     *
+     * @author arichard
+     */
+    private static final class TestFragment implements ISysONExplorerFragment {
+
+        private final String id;
+
+        private final String kind;
+
+        private final String label;
+
+        private final List<String> iconURL;
+
+        private TestFragment(String id, String kind, String label, List<String> iconURL) {
+            this.id = id;
+            this.kind = kind;
+            this.label = label;
+            this.iconURL = iconURL;
+        }
+
+        @Override
+        public String getId() {
+            return this.id;
+        }
+
+        @Override
+        public String getTooltip() {
+            return this.label;
+        }
+
+        @Override
+        public String getLabel() {
+            return this.label;
+        }
+
+        @Override
+        public String getKind() {
+            return this.kind;
+        }
+
+        @Override
+        public Object getParent() {
+            return null;
+        }
+
+        @Override
+        public List<String> getIconURL() {
+            return this.iconURL;
+        }
+
+        @Override
+        public boolean hasChildren(IEditingContext editingContext, List<RepresentationMetadata> existingRepresentations, List<String> expandedIds, List<String> activeFilterIds) {
+            return false;
+        }
+
+        @Override
+        public List<Object> getChildren(IEditingContext editingContext, List<RepresentationMetadata> existingRepresentations, List<String> expandedIds, List<String> activeFilterIds) {
+            return List.of();
+        }
+
+        @Override
+        public boolean isEditable() {
+            return false;
+        }
+
+        @Override
+        public boolean isDeletable() {
+            return false;
+        }
+
+        @Override
+        public boolean isSelectable() {
+            return true;
+        }
+    }
+}