[4286] Make default explorer DnD work only for the default explorer

Bug: eclipse-sirius#4286
Signed-off-by: Gwendal Daniel <[email protected]>

CHANGELOG.adoc

@@ -103,6 +103,8 @@ This is now fixed.
 - https://github.com/eclipse-sirius/sirius-web/issues/4234[#4234] [table] Make table's row resizable
 - https://github.com/eclipse-sirius/sirius-web/issues/4254[#4254] [sirius-web] Make explorer services reusable
 - https://github.com/eclipse-sirius/sirius-web/issues/4264[#4264] [table] Reset all custom rows height
+- https://github.com/eclipse-sirius/sirius-web/issues/4286[#4286] [sirius-web] Make default explorer drag and drop work only for the default explorer
+Downstream applications with a custom explorer that relies on `ExplorerDropTreeItemHandler` now need to provide their own `IDropTreeItemHandler` to support drag and drop in their explorer. 
 
 
 == v2024.11.0

packages/sirius-web/backend/sirius-web-application/src/main/java/org/eclipse/sirius/web/application/studio/services/representations/DomainDropTreeItemHandler.java

@@ -0,0 +1,54 @@
+/*******************************************************************************
+ * Copyright (c) 2024 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.sirius.web.application.studio.services.representations;
+
+import org.eclipse.sirius.components.collaborative.trees.api.IDropTreeItemHandler;
+import org.eclipse.sirius.components.core.api.IEditingContext;
+import org.eclipse.sirius.components.core.api.IObjectService;
+import org.eclipse.sirius.components.trees.Tree;
+import org.eclipse.sirius.components.view.emf.IRepresentationDescriptionIdProvider;
+import org.eclipse.sirius.components.view.emf.IViewRepresentationDescriptionSearchService;
+import org.eclipse.sirius.web.application.views.explorer.services.ExplorerDescriptionProvider;
+import org.eclipse.sirius.web.application.views.explorer.services.ExplorerDropTreeItemHandler;
+import org.eclipse.sirius.web.domain.services.api.IMessageService;
+import org.springframework.stereotype.Service;
+
+/**
+ * Provides the drop tree item tool for the Domain explorer by DSL explorer.
+ *
+ * @author gdaniel
+ */
+@Service
+public class DomainDropTreeItemHandler extends ExplorerDropTreeItemHandler implements IDropTreeItemHandler {
+
+    private final IViewRepresentationDescriptionSearchService viewRepresentationDescriptionSearchService;
+
+    public DomainDropTreeItemHandler(IObjectService objectService, IMessageService messageService, IViewRepresentationDescriptionSearchService viewRepresentationDescriptionSearchService) {
+        super(objectService, messageService);
+        this.viewRepresentationDescriptionSearchService = viewRepresentationDescriptionSearchService;
+    }
+
+    @Override
+    public boolean canHandle(IEditingContext editingContext, Tree tree) {
+        boolean result = false;
+        if (tree.getId().startsWith(ExplorerDescriptionProvider.PREFIX)
+                && tree.getDescriptionId().startsWith(IRepresentationDescriptionIdProvider.PREFIX)) {
+            var optionalViewTreeDescription = this.viewRepresentationDescriptionSearchService.findById(editingContext, tree.getDescriptionId());
+            if (optionalViewTreeDescription.isPresent()) {
+                result = optionalViewTreeDescription.get().getName().equals(DomainViewTreeDescriptionProvider.DOMAIN_EXPLORER_DESCRIPTION_NAME);
+            }
+        }
+        return result;
+    }
+
+}

packages/sirius-web/backend/sirius-web-application/src/main/java/org/eclipse/sirius/web/application/views/explorer/services/ExplorerDropTreeItemHandler.java

@@ -54,8 +54,9 @@ public ExplorerDropTreeItemHandler(IObjectService objectService, IMessageService
     }
 
     @Override
-    public boolean canHandle(Tree tree) {
-        return tree.getId().startsWith(ExplorerDescriptionProvider.PREFIX);
+    public boolean canHandle(IEditingContext editingContext, Tree tree) {
+        return tree.getId().startsWith(ExplorerDescriptionProvider.PREFIX)
+                && Objects.equals(tree.getDescriptionId(), ExplorerDescriptionProvider.DESCRIPTION_ID);
     }
 
     @Override

packages/trees/backend/sirius-components-collaborative-trees/src/main/java/org/eclipse/sirius/components/collaborative/trees/api/IDropTreeItemHandler.java

@@ -24,7 +24,7 @@
  */
 public interface IDropTreeItemHandler {
 
-    boolean canHandle(Tree tree);
+    boolean canHandle(IEditingContext editingContext, Tree tree);
 
     IStatus handle(IEditingContext editingContext, Tree tree, DropTreeItemInput input);
 

packages/trees/backend/sirius-components-collaborative-trees/src/main/java/org/eclipse/sirius/components/collaborative/trees/handlers/DropTreeItemEventHandler.java

@@ -74,7 +74,7 @@ public void handle(One<IPayload> payloadSink, Many<ChangeDescription> changeDesc
         ChangeDescription changeDescription = new ChangeDescription(ChangeKind.NOTHING, treeInput.representationId(), treeInput);
 
         if (treeInput instanceof DropTreeItemInput input) {
-            var optionalDropHandler = this.dropTreeItemHandlers.stream().filter(provider -> provider.canHandle(tree)).findFirst();
+            var optionalDropHandler = this.dropTreeItemHandlers.stream().filter(provider -> provider.canHandle(editingContext, tree)).findFirst();
 
             var status = optionalDropHandler
                     .map(provider -> provider.handle(editingContext, tree, input))