[2182] Provide a way for downstream applications to extend ISysMLMoveElementService

CHANGELOG.adoc

@@ -20,6 +20,8 @@
 
 - https://github.com/eclipse-syson/syson/issues/2198[#2198] [diagrams] Improve diagram-to-diagram drag and drop to support dropping multiple graphical nodes at once, leveraging Sirius Web's `droppedNodes` and `droppedElements` variables.
 - https://github.com/eclipse-syson/syson/issues/2194[#2194] [diagrams] Properly report feedback messages to user when using _ISysMLMoveElementService_.
+- https://github.com/eclipse-syson/syson/issues/2182[#2182] [services] Provide a way for downstream applications to extend _ISysMLMoveElementService_;
+
 
 === New features
 

backend/application/syson-application/src/test/java/org/eclipse/syson/SysMLMoveElementServiceDelegateIntegrationTests.java

@@ -0,0 +1,180 @@
+/*******************************************************************************
+ * 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;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.eclipse.sirius.components.diagrams.tests.DiagramEventPayloadConsumer.assertRefreshedDiagramThat;
+
+import com.jayway.jsonpath.JsonPath;
+
+import java.text.MessageFormat;
+import java.time.Duration;
+import java.util.List;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
+
+import org.eclipse.sirius.components.collaborative.diagrams.dto.DiagramEventInput;
+import org.eclipse.sirius.components.collaborative.diagrams.dto.DiagramRefreshedEventPayload;
+import org.eclipse.sirius.components.collaborative.diagrams.dto.DropNodesInput;
+import org.eclipse.sirius.components.core.api.IFeedbackMessageService;
+import org.eclipse.sirius.components.core.api.SuccessPayload;
+import org.eclipse.sirius.components.diagrams.Diagram;
+import org.eclipse.sirius.components.diagrams.layoutdata.Position;
+import org.eclipse.sirius.components.representations.Message;
+import org.eclipse.sirius.components.representations.MessageLevel;
+import org.eclipse.sirius.web.tests.services.api.IGivenInitialServerState;
+import org.eclipse.syson.application.controllers.diagrams.testers.DropNodesWithMessageMutationRunner;
+import org.eclipse.syson.application.data.GeneralViewFlowUsageProjectData;
+import org.eclipse.syson.services.api.IDefaultSysMLMoveElementService;
+import org.eclipse.syson.services.api.ISysMLMoveElementServiceDelegate;
+import org.eclipse.syson.services.api.MoveStatus;
+import org.eclipse.syson.services.diagrams.api.IGivenDiagramSubscription;
+import org.eclipse.syson.sysml.Element;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
+import org.springframework.transaction.annotation.Transactional;
+
+import reactor.core.publisher.Flux;
+import reactor.test.StepVerifier;
+
+/**
+ * Integration tests for {@link ISysMLMoveElementServiceDelegate}.
+ *
+ * @author Arthur Daussy
+ */
+@Transactional
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@Import(SysMLMoveElementServiceDelegateIntegrationTests.SysMLMoveElementServiceDelegateTestConfiguration.class)
+public class SysMLMoveElementServiceDelegateIntegrationTests extends AbstractIntegrationTests {
+
+    private static final String DROP_NODES_TYPENAME = "$.data.dropNodes.__typename";
+
+    private static final String DROP_NODES_MESSAGE_BODY = "$.data.dropNodes.messages[0].body";
+
+    private static final String DROP_NODES_MESSAGE_LEVEL = "$.data.dropNodes.messages[0].level";
+
+    private static final String EXPECTED_FEEDBACK_MESSAGE = "Moved screen to Package1";
+
+    @Autowired
+    private IGivenInitialServerState givenInitialServerState;
+
+    @Autowired
+    private IGivenDiagramSubscription givenDiagramSubscription;
+
+    @Autowired
+    private DropNodesWithMessageMutationRunner dropNodeRunner;
+
+    private Flux<DiagramRefreshedEventPayload> givenSubscriptionToDiagram() {
+        var diagramEventInput = new DiagramEventInput(UUID.randomUUID(),
+                GeneralViewFlowUsageProjectData.EDITING_CONTEXT_ID,
+                GeneralViewFlowUsageProjectData.GraphicalIds.DIAGRAM_ID);
+        return this.givenDiagramSubscription.subscribe(diagramEventInput);
+    }
+
+    @BeforeEach
+    public void beforeEach() {
+        this.givenInitialServerState.initialize();
+    }
+
+    @DisplayName("GIVEN a move delegate, WHEN Screen is dropped into Package 1, THEN the delegate moves it and returns a feedback message")
+    @GivenSysONServer({ GeneralViewFlowUsageProjectData.SCRIPT_PATH })
+    @Test
+    public void moveScreenPartWithDelegate() {
+        var flux = this.givenSubscriptionToDiagram();
+
+        AtomicReference<Diagram> diagram = new AtomicReference<>();
+
+        Consumer<Object> initialDiagramContentConsumer = assertRefreshedDiagramThat(diagram::set);
+
+        Runnable dropScreenPartFromDiagramToPackage = () -> {
+            var input = new DropNodesInput(
+                    UUID.randomUUID(),
+                    GeneralViewFlowUsageProjectData.EDITING_CONTEXT_ID,
+                    GeneralViewFlowUsageProjectData.GraphicalIds.DIAGRAM_ID,
+                    List.of(GeneralViewFlowUsageProjectData.GraphicalIds.SCREEN_PART_ID),
+                    null,
+                    List.of(new Position(0, 0)));
+            var result = this.dropNodeRunner.run(input);
+            String typename = JsonPath.read(result.data(), DROP_NODES_TYPENAME);
+            assertThat(typename).isEqualTo(SuccessPayload.class.getSimpleName());
+            String messageBody = JsonPath.read(result.data(), DROP_NODES_MESSAGE_BODY);
+            assertThat(messageBody).isEqualTo(EXPECTED_FEEDBACK_MESSAGE);
+            String messageLevel = JsonPath.read(result.data(), DROP_NODES_MESSAGE_LEVEL);
+            assertThat(messageLevel).isEqualTo(MessageLevel.INFO.toString());
+        };
+
+        Consumer<Object> updatedDiagramContentConsumer = assertRefreshedDiagramThat(newDiagram -> {
+            assertThat(newDiagram.getNodes())
+                    .extracting(org.eclipse.sirius.components.diagrams.Node::getTargetObjectId)
+                    .contains(GeneralViewFlowUsageProjectData.SemanticIds.SCREEN_PART);
+        });
+
+        StepVerifier.create(flux)
+                .consumeNextWith(initialDiagramContentConsumer)
+                .then(dropScreenPartFromDiagramToPackage)
+                .consumeNextWith(updatedDiagramContentConsumer)
+                .thenCancel()
+                .verify(Duration.ofSeconds(10));
+    }
+
+    /**
+     * Test configuration used to activate the move delegate only for this integration test.
+     */
+    @TestConfiguration
+    static class SysMLMoveElementServiceDelegateTestConfiguration {
+
+        @Bean
+        ISysMLMoveElementServiceDelegate feedbackMoveElementServiceDelegate(IDefaultSysMLMoveElementService defaultMoveElementService, IFeedbackMessageService feedbackMessageService) {
+            return new FeedbackMoveElementServiceDelegate(defaultMoveElementService, feedbackMessageService);
+        }
+    }
+
+    /**
+     * Test move delegate which behaves like the default implementation and emits a feedback message.
+     */
+    private static final class FeedbackMoveElementServiceDelegate implements ISysMLMoveElementServiceDelegate {
+
+        private final IDefaultSysMLMoveElementService defaultMoveElementService;
+
+        private final IFeedbackMessageService feedbackMessageService;
+
+        FeedbackMoveElementServiceDelegate(IDefaultSysMLMoveElementService defaultMoveElementService, IFeedbackMessageService feedbackMessageService) {
+            this.defaultMoveElementService = Objects.requireNonNull(defaultMoveElementService);
+            this.feedbackMessageService = Objects.requireNonNull(feedbackMessageService);
+        }
+
+        @Override
+        public boolean canHandle(Element element, Element newParent) {
+            return true;
+        }
+
+        @Override
+        public MoveStatus moveSemanticElement(Element element, Element newParent) {
+            MoveStatus moveStatus = this.defaultMoveElementService.moveSemanticElement(element, newParent);
+            if (moveStatus.isSuccess() && element != newParent) {
+                String elementLabel = element.getDeclaredName();
+                String parentLabel = newParent.getDeclaredName();
+                this.feedbackMessageService.addFeedbackMessage(new Message(MessageFormat.format("Moved {0} to {1}", elementLabel, parentLabel), MessageLevel.INFO));
+            }
+            return moveStatus;
+        }
+    }
+}

backend/application/syson-application/src/test/java/org/eclipse/syson/application/data/GeneralViewFlowUsageProjectData.java

@@ -23,12 +23,14 @@ public class GeneralViewFlowUsageProjectData {
     public static final String SCRIPT_PATH = "/scripts/database-content/GeneralView-FlowUsage.sql";
 
     /**
-     * Ids of the graphical elements elements.
+     * Ids of the graphical elements.
      */
     public static final class GraphicalIds {
         public static final String DIAGRAM_ID = "2a1b62cf-36ea-41d2-8433-8ff781b3f4e5";
 
         public static final String CONNECTION_EDGE_ID = "7f3367d5-a200-339b-820a-2408e5b82c84";
+
+        public static final String SCREEN_PART_ID = "946dc191-c8df-3f97-96a9-02cce98768f4";
     }
 
     /**
@@ -41,5 +43,9 @@ public static final class SemanticIds {
 
         public static final String VIDEO_SIGNAL_ID = "d9b2dd49-4bae-44a7-8137-73bcaf0a2d5e";
 
+        public static final String SCREEN_PART = "7776b0d9-287c-441f-b203-36b7ba41a7c6";
+
+        public static final String PACKAGE_1 = "8cb4376f-fe0d-4501-abcb-05eac69e766c";
+
     }
 }

backend/services/syson-services/src/main/java/org/eclipse/syson/services/DefaultSysMLMoveElementService.java

@@ -0,0 +1,138 @@
+/*******************************************************************************
+ * Copyright (c) 2025, 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.services;
+
+import java.util.Objects;
+
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.syson.services.api.IDefaultSysMLMoveElementService;
+import org.eclipse.syson.services.api.ISysMLMoveElementCheckerService;
+import org.eclipse.syson.services.api.MoveStatus;
+import org.eclipse.syson.sysml.Element;
+import org.eclipse.syson.sysml.FeatureMembership;
+import org.eclipse.syson.sysml.Import;
+import org.eclipse.syson.sysml.Membership;
+import org.eclipse.syson.sysml.MembershipExpose;
+import org.eclipse.syson.sysml.OwningMembership;
+import org.eclipse.syson.sysml.Package;
+import org.eclipse.syson.sysml.SysmlFactory;
+import org.eclipse.syson.sysml.SysmlPackage;
+import org.springframework.stereotype.Service;
+
+/**
+ * Default {@link IDefaultSysMLMoveElementService} for SysML elements.
+ *
+ * @author Arthur Daussy
+ */
+@Service
+public class DefaultSysMLMoveElementService implements IDefaultSysMLMoveElementService {
+
+    private final DeleteService deleteService;
+
+    private final UtilService utilService;
+
+    private final ISysMLMoveElementCheckerService moveElementCheckerService;
+
+    public DefaultSysMLMoveElementService(ISysMLMoveElementCheckerService moveElementCheckerService) {
+        this.moveElementCheckerService = Objects.requireNonNull(moveElementCheckerService);
+        this.deleteService = new DeleteService();
+        this.utilService = new UtilService();
+    }
+
+    @Override
+    public MoveStatus moveSemanticElement(Element element, Element newParent) {
+        final MoveStatus moveStatus;
+        MoveStatus canMoveStatus = this.moveElementCheckerService.canMove(element, newParent);
+        if (!canMoveStatus.isSuccess()) {
+            moveStatus = canMoveStatus;
+        } else if (element == newParent) {
+            moveStatus = MoveStatus.buildSuccess();
+        } else if (newParent instanceof Membership) {
+            moveStatus = MoveStatus.buildFailure("Membership can't be used as a target of a move");
+        } else if (element instanceof Import imprt) {
+            newParent.getOwnedRelationship().add(0, imprt);
+            moveStatus = MoveStatus.buildSuccess();
+        } else {
+            moveStatus = this.moveWithMembership(element, newParent);
+        }
+        return moveStatus;
+    }
+
+    /**
+     * Moves the owning membership of {@code element} to {@code parent}.
+     * <p>
+     * This method may create a new membership in {@code parent}, potentially with a different type than
+     * {@code element.getOwningMembership()}. For example, an element moved into a package will have an
+     * {@link OwningMembership} instance as its parent, regardless of its original containing membership.
+     * </p>
+     *
+     * @param element
+     *            the element that has been dropped
+     * @param parent
+     *            the element inside which the drop has been performed
+     * @return true if the given element has been moved
+     */
+    private MoveStatus moveWithMembership(Element element, Element parent) {
+        final MoveStatus moveStatus;
+
+        if (element != null && element.eContainer() instanceof Membership currentMembership) {
+            if (parent instanceof Package) {
+                // the expected membership should be an OwningMembership
+                if (currentMembership instanceof FeatureMembership) {
+                    var owningMembership = SysmlFactory.eINSTANCE.createOwningMembership();
+                    // Add the new membership to its container first to make sure its content stays in the same
+                    // resource. Otherwise the cross-referencer will delete all the references pointing to its
+                    // related element, which will have unexpected results on the model.
+                    parent.getOwnedRelationship().add(owningMembership);
+                    moveStatus = MoveStatus.buildSuccess();
+                    owningMembership.getOwnedRelatedElement().add(element);
+                    // If the currentMembership is exposed, we need to add new links between the MembershipExposes and
+                    // the new owningMembership
+                    var eInverseRelatedElements = this.utilService.getEInverseRelatedElements(currentMembership, SysmlPackage.eINSTANCE.getMembershipImport_ImportedMembership());
+                    for (EObject eObject : eInverseRelatedElements) {
+                        if (eObject instanceof MembershipExpose membershipExpose) {
+                            membershipExpose.setImportedMembership(owningMembership);
+                        }
+                    }
+                    this.deleteService.deleteFromModel(currentMembership);
+                } else {
+                    parent.getOwnedRelationship().add(currentMembership);
+                    moveStatus = MoveStatus.buildSuccess();
+                }
+            } else {
+                // the expected membership should be a FeatureMembership
+                if (currentMembership instanceof FeatureMembership) {
+                    parent.getOwnedRelationship().add(currentMembership);
+                    moveStatus = MoveStatus.buildSuccess();
+                } else {
+                    var featureMembership = SysmlFactory.eINSTANCE.createFeatureMembership();
+                    parent.getOwnedRelationship().add(featureMembership);
+                    moveStatus = MoveStatus.buildSuccess();
+                    featureMembership.getOwnedRelatedElement().add(element);
+                    // If the currentMembership is exposed, we need to add new links between the MembershipExposes and
+                    // the new featureMembership
+                    var eInverseRelatedElements = this.utilService.getEInverseRelatedElements(currentMembership, SysmlPackage.eINSTANCE.getMembershipImport_ImportedMembership());
+                    for (EObject eObject : eInverseRelatedElements) {
+                        if (eObject instanceof MembershipExpose membershipExpose) {
+                            membershipExpose.setImportedMembership(featureMembership);
+                        }
+                    }
+                    this.deleteService.deleteFromModel(currentMembership);
+                }
+            }
+        } else {
+            moveStatus = MoveStatus.buildFailure("Element is not contained in a membership");
+        }
+        return moveStatus;
+    }
+}