[fix] Disable D&D of TreeItems inside Explorer view

Signed-off-by: Axel RICHARD <[email protected]>

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/explorer/DropTreeItemHandler.java

@@ -0,0 +1,53 @@
+/*******************************************************************************
+ * 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.syson.application.explorer;
+
+import org.eclipse.sirius.components.collaborative.api.ChangeDescription;
+import org.eclipse.sirius.components.collaborative.trees.api.ITreeEventHandler;
+import org.eclipse.sirius.components.collaborative.trees.api.ITreeInput;
+import org.eclipse.sirius.components.collaborative.trees.dto.DropTreeItemInput;
+import org.eclipse.sirius.components.core.api.IEditingContext;
+import org.eclipse.sirius.components.core.api.IPayload;
+import org.eclipse.sirius.components.core.api.SuccessPayload;
+import org.eclipse.sirius.components.trees.Tree;
+import org.eclipse.sirius.components.trees.description.TreeDescription;
+import org.springframework.context.annotation.Primary;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Service;
+
+import reactor.core.publisher.Sinks.Many;
+import reactor.core.publisher.Sinks.One;
+
+/**
+ * Disable the D&D inside the Explorer view. Sirius Web now allows the D&D of tree items inside the Explorer view, but
+ * the default behavior is not suitable for SysON. Indeed, when an Element is D&D, SysON should also D&D its Membership
+ * container at the same time.
+ *
+ * @author arichard
+ */
+@Service
+@Primary
+@Order(value = Ordered.HIGHEST_PRECEDENCE)
+public class DropTreeItemHandler implements ITreeEventHandler {
+
+    @Override
+    public boolean canHandle(ITreeInput treeInput) {
+        return treeInput instanceof DropTreeItemInput;
+    }
+
+    @Override
+    public void handle(One<IPayload> payloadSink, Many<ChangeDescription> changeDescriptionSink, IEditingContext editingContext, TreeDescription treeDescription, Tree tree, ITreeInput treeInput) {
+        payloadSink.tryEmitValue(new SuccessPayload(treeInput.id()));
+    }
+}