[1363] Add a menu action that will hide children that don't have children and will reveal the others.

Bug: #1363
Signed-off-by: Michaël Charfadi <michael.charfadi@obeosoft.com>

Author: mcharfadi

CHANGELOG.adoc

@@ -94,6 +94,7 @@ All existing SysON _DiagramDescriptions_ (i.g. _General View_, _Interconnection
 - https://github.com/eclipse-syson/syson/issues/1346[#1346] [general-view] Improve _direct edit_ tool on `ConstraintUsage` to be able to edit basic expressions.
 - https://github.com/eclipse-syson/syson/issues/1310[#1310] [metamodel] Revert remove derived flag for `ViewUsage#exposedElement` feature.
 - https://github.com/eclipse-syson/syson/issues/1359[#1359] [export] Implement textual export of `ViewUsage`.
+- https://github.com/eclipse-syson/syson/issues/1346[#1346] [general-view] Add a reveal only valued content action on the manage visibility node action modal that will hide children that don't have children and will reveal the others.
 
 === New features
 

…wManageVisibilityNodeActionProvider.java …wManageVisibilityNodeActionProvider.javabackend/views/syson-diagram-general-view/src/main/java/org/eclipse/syson/diagram/general/view/services/GeneralViewManageVisibilityNodeActionProvider.java renamed to backend/views/syson-diagram-general-view/src/main/java/org/eclipse/syson/diagram/general/view/services/nodeactions/managevisibility/GeneralViewManageVisibilityNodeActionProvider.java backend/views/syson-diagram-general-view/src/main/java/org/eclipse/syson/diagram/general/view/services/GeneralViewManageVisibilityNodeActionProvider.java renamed to backend/views/syson-diagram-general-view/src/main/java/org/eclipse/syson/diagram/general/view/services/nodeactions/managevisibility/GeneralViewManageVisibilityNodeActionProvider.java

@@ -10,7 +10,7 @@
  * Contributors:
  *     Obeo - initial API and implementation
  *******************************************************************************/
-package org.eclipse.syson.diagram.general.view.services;
+package org.eclipse.syson.diagram.general.view.services.nodeactions.managevisibility;
 
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;

backend/views/syson-diagram-general-view/src/main/java/org/eclipse/syson/diagram/general/view/services/nodeactions/managevisibility/GeneralViewManageVisibilityRevealValuedContentAction.java

@@ -0,0 +1,44 @@
+/*******************************************************************************
+ * Copyright (c) 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
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.diagram.general.view.services.nodeactions.managevisibility;
+
+import org.eclipse.sirius.components.collaborative.diagrams.api.nodeactions.IManageVisibilityMenuActionProvider;
+import org.eclipse.sirius.components.collaborative.diagrams.dto.managevisibility.ManageVisibilityAction;
+import org.eclipse.sirius.components.core.api.IEditingContext;
+import org.eclipse.sirius.components.diagrams.IDiagramElement;
+import org.eclipse.sirius.components.diagrams.Node;
+import org.eclipse.sirius.components.diagrams.description.DiagramDescription;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+/**
+ * Menu action on the manage visibility modal that will reveal children that also have children.
+ *
+ * @author mcharfadi
+ */
+@Service
+public class GeneralViewManageVisibilityRevealValuedContentAction implements IManageVisibilityMenuActionProvider {
+
+    public static final String ACTION_ID = "manage_visibility_menu_reveal_valued_content_action";
+
+    @Override
+    public boolean canHandle(IEditingContext editingContext, DiagramDescription diagramDescription, IDiagramElement diagramElement) {
+        return diagramElement instanceof Node node && !node.getChildNodes().isEmpty();
+    }
+
+    @Override
+    public List<ManageVisibilityAction> handle(IEditingContext editingContext, DiagramDescription diagramDescription, IDiagramElement diagramElement) {
+        return List.of(new ManageVisibilityAction(ACTION_ID, "Reveal valued content only"));
+    }
+}

backend/views/syson-diagram-general-view/src/main/java/org/eclipse/syson/diagram/general/view/services/nodeactions/managevisibility/GeneralViewManageVisibilityRevealValuedContentHandler.java

@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * Copyright (c) 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
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.diagram.general.view.services.nodeactions.managevisibility;
+
+import org.eclipse.sirius.components.collaborative.diagrams.api.IDiagramContext;
+import org.eclipse.sirius.components.collaborative.diagrams.api.IDiagramQueryService;
+import org.eclipse.sirius.components.collaborative.diagrams.api.nodeactions.IManageVisibilityMenuActionHandler;
+import org.eclipse.sirius.components.core.api.IEditingContext;
+import org.eclipse.sirius.components.diagrams.IDiagramElement;
+import org.eclipse.sirius.components.diagrams.Node;
+import org.eclipse.sirius.components.diagrams.events.HideDiagramElementEvent;
+import org.eclipse.sirius.components.representations.IStatus;
+import org.eclipse.sirius.components.representations.Success;
+import org.springframework.stereotype.Service;
+
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+
+/**
+ * Handler for the menu action on the manage visibility modal that will reveal children that also have children.
+ *
+ * @author mcharfadi
+ */
+@Service
+public class GeneralViewManageVisibilityRevealValuedContentHandler implements IManageVisibilityMenuActionHandler {
+
+    private final IDiagramQueryService diagramQueryService;
+
+    public GeneralViewManageVisibilityRevealValuedContentHandler(IDiagramQueryService diagramQueryService) {
+        this.diagramQueryService = Objects.requireNonNull(diagramQueryService);
+    }
+
+    @Override
+    public boolean canHandle(IEditingContext editingContext, IDiagramContext diagramContext, IDiagramElement diagramElement, String actionId) {
+        return actionId.equals(GeneralViewManageVisibilityRevealValuedContentAction.ACTION_ID);
+    }
+
+    @Override
+    public IStatus handle(IEditingContext editingContext, IDiagramContext diagramContext, IDiagramElement diagramElement, String actionId) {
+        Optional<Node> optionalNode = this.diagramQueryService.findNodeById(diagramContext.getDiagram(), diagramElement.getId());
+        Set<String> nodesToReveal = new HashSet<>();
+        Set<String> nodesToHide = new HashSet<>();
+        if (optionalNode.isPresent()) {
+            optionalNode.get().getChildNodes().forEach(node -> {
+                if (node.getChildNodes().isEmpty()) {
+                   nodesToHide.add(node.getId());
+                } else {
+                    nodesToReveal.add(node.getId());
+                }
+            });
+            diagramContext.getDiagramEvents().add(new HideDiagramElementEvent(nodesToReveal, false));
+            diagramContext.getDiagramEvents().add(new HideDiagramElementEvent(nodesToHide, true));
+        }
+        return new Success();
+    }
+
+}