[1368] Add an edge representation for FeatureValue linking two Features

Bug: #1368
Signed-off-by: Arthur Daussy <arthur.daussy@obeo.fr>

Author: adaussy

CHANGELOG.adoc

@@ -100,6 +100,7 @@ All existing SysON _DiagramDescriptions_ (i.g. _General View_, _Interconnection
 - https://github.com/eclipse-syson/syson/issues/1350[#1350] [general-view] Improve _direct edit_ tool on `Feature` to be able to edit `FeatureValue` with basic expressions.
 - https://github.com/eclipse-syson/syson/issues/1363[#1363] [general-view] Add a reveal only valued content action on the manage visibility node action that will hide empty graphical compartments and will reveal the others.
 - https://github.com/eclipse-syson/syson/issues/1357[#1357] [syson] Add support for `Resource` and `EAnnotation` in `SysONReadOnlyObjectPredicateDelegate`.
+- https://github.com/eclipse-syson/syson/issues/1368[#1368] [general-view] Add an edge representation for `FeatureValue` linking two `Features`.
 
 === New features
 

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/configuration/SysMLv2PropertiesConfigurer.java

@@ -172,6 +172,7 @@ private FormDescription createDetailsView() {
         pageCore.getGroups().add(this.createExtraRequirementConstraintMembershipPropertiesGroup());
         pageCore.getGroups().add(this.createExtraAcceptActionUsagePropertiesGroup());
         pageCore.getGroups().add(this.createExtraTransitionSourceTargetPropertiesGroup());
+        pageCore.getGroups().add(this.createFeatureValuePropertiesGroup());
 
         PageDescription pageAdvanced = FormFactory.eINSTANCE.createPageDescription();
         pageAdvanced.setName("SysON-DetailsView-Advanced");
@@ -186,6 +187,29 @@ private FormDescription createDetailsView() {
         return form;
     }
 
+    /**
+     * Creates a group to display the value of a Feature or FeatureValue.
+     * 
+     * @return a {@link GroupDescription}
+     */
+    private GroupDescription createFeatureValuePropertiesGroup() {
+        GroupDescription group = FormFactory.eINSTANCE.createGroupDescription();
+        group.setDisplayMode(GroupDisplayMode.LIST);
+        group.setName("Value");
+        group.setLabelExpression("");
+        group.setSemanticCandidatesExpression(AQLUtils.getSelfServiceCallExpression("getFeatureValue"));
+
+        TextAreaDescription expressionWidget = FormFactory.eINSTANCE.createTextAreaDescription();
+        expressionWidget.setName("ValueExpression");
+        expressionWidget.setLabelExpression("Value");
+        expressionWidget.setValueExpression(AQLUtils.getSelfServiceCallExpression("getValueExpression"));
+        expressionWidget.setIsEnabledExpression("aql:false");
+
+        group.getChildren().add(expressionWidget);
+
+        return group;
+    }
+
     private GroupDescription createCorePropertiesGroup() {
         GroupDescription group = FormFactory.eINSTANCE.createGroupDescription();
         group.setDisplayMode(GroupDisplayMode.LIST);

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/services/DetailsViewService.java

@@ -69,6 +69,8 @@
 import org.eclipse.syson.sysml.TransitionUsage;
 import org.eclipse.syson.sysml.Type;
 import org.eclipse.syson.sysml.ViewUsage;
+import org.eclipse.syson.sysml.textual.SysMLElementSerializer;
+import org.eclipse.syson.sysml.textual.utils.FileNameDeresolver;
 
 /**
  * Java services needed to execute the AQL expressions used in the {@link SysMLv2PropertiesConfigurer}.
@@ -566,11 +568,49 @@ public Element setNewDocumentationValue(Element self, String newValue) {
         return self;
     }
 
+    /**
+     * Gets the {@link FeatureValue} from a {@link Feature} with a {@link FeatureValue} or a {@link FeatureValue}.
+     * 
+     * @param self
+     *            a {@link FeatureValue} or {@link Feature}
+     * @return a {@link FeatureValue} or <code>null</code>
+     */
+    public Element getFeatureValue(Element self) {
+        Element result = null;
+        if (self instanceof FeatureValue featureValue && featureValue.getValue() != null) {
+            result = featureValue;
+        } else if (self instanceof Feature feature && feature.getValuation() != null && feature.getValuation().getValue() != null) {
+            result = feature.getValuation();
+        }
+        return result;
+    }
+
+    /**
+     * Gets the textual representation of the value of a {@link FeatureValue}.
+     * 
+     * @param featureValue
+     *            a {@link FeatureValue}
+     * @return a textual representation of the value (or empty string if none)
+     */
+    public String getValueExpressionTextualRepresentation(FeatureValue featureValue) {
+        Expression value = featureValue.getValue();
+        String result = "";
+        if (value != null) {
+            String textualFormat = new SysMLElementSerializer("\n", "\t", new FileNameDeresolver(), s -> {
+                // Do nothing for now
+            }).doSwitch(value);
+            if (textualFormat != null) {
+                result = textualFormat;
+            }
+        }
+        return result;
+    }
+
     /**
      * Returns the element that owns the visibility feature of the given element.
      *
      * @param self
-     *         An element for which the visibility owner is being searched.
+     *            An element for which the visibility owner is being searched.
      * @return the element that owns the visibility feature of the given element
      */
     public Element getVisibilityPropertyOwner(Element self) {
@@ -584,7 +624,7 @@ public Element getVisibilityPropertyOwner(Element self) {
      * Returns the enumeration literals for the visibility feature of the given element.
      *
      * @param self
-     *         An element for which the list of visibility literals are being searched.
+     *            An element for which the list of visibility literals are being searched.
      * @return the enumeration literals for the visibility feature of the given element.
      */
     public List<EEnumLiteral> getVisibilityEnumLiterals(Element self) {
@@ -599,7 +639,7 @@ public List<EEnumLiteral> getVisibilityEnumLiterals(Element self) {
      * Returns the visibility value of the given element.
      *
      * @param self
-     *         An element for which the list of visibility literals are being searched.
+     *            An element for which the list of visibility literals are being searched.
      * @return the current value of the visibility feature of the given element.
      */
     public EEnumLiteral getVisibilityValue(Element self) {
@@ -614,11 +654,11 @@ public EEnumLiteral getVisibilityValue(Element self) {
      * Sets the visibility value of the given element.
      *
      * @param self
-     *         An element for which the list of visibility literals are being searched.
+     *            An element for which the list of visibility literals are being searched.
      * @param newValue
-     *         the value to set.
+     *            the value to set.
      * @return <code>true</code> if the visibility feature of the given element has been properly set and
-     * <code>false</code> otherwise.
+     *         <code>false</code> otherwise.
      */
     public boolean setVisibilityValue(Element self, Object newValue) {
         boolean result = false;
@@ -655,7 +695,7 @@ private void handleImplied(Element element, EStructuralFeature eStructuralFeatur
      * guarantee that it is well formed after its call.
      *
      * @param aau
-     *         an {@link AcceptActionUsage}
+     *            an {@link AcceptActionUsage}
      */
     private void checkAndRepairAcceptActionUsageStructure(AcceptActionUsage aau) {
         this.checkAndRepairAcceptActionUsagePayload(aau);

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

@@ -12,20 +12,32 @@
  *******************************************************************************/
 package org.eclipse.syson.application.controllers.diagrams.general.view;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.fail;
+
 import java.time.Duration;
+import java.util.List;
+import java.util.Optional;
 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.diagrams.Diagram;
+import org.eclipse.sirius.components.diagrams.Edge;
+import org.eclipse.sirius.components.diagrams.InsideLabel;
 import org.eclipse.sirius.components.diagrams.tests.graphql.EditLabelMutationRunner;
 import org.eclipse.sirius.components.diagrams.tests.graphql.InitialDirectEditElementLabelQueryRunner;
+import org.eclipse.sirius.components.diagrams.tests.navigation.DiagramNavigator;
 import org.eclipse.sirius.web.tests.services.api.IGivenInitialServerState;
 import org.eclipse.syson.AbstractIntegrationTests;
+import org.eclipse.syson.application.controllers.diagrams.testers.DeleteFromDiagramRunner;
+import org.eclipse.syson.application.controllers.diagrams.testers.DeleteFromDiagramTester;
 import org.eclipse.syson.application.controllers.diagrams.testers.DirectEditInitialLabelTester;
 import org.eclipse.syson.application.controllers.diagrams.testers.DirectEditTester;
 import org.eclipse.syson.application.data.GeneralViewItemAndAttributeProjectData;
+import org.eclipse.syson.services.diagrams.DiagramComparator;
 import org.eclipse.syson.services.diagrams.api.IGivenDiagramReference;
 import org.eclipse.syson.services.diagrams.api.IGivenDiagramSubscription;
 import org.junit.jupiter.api.AfterEach;
@@ -65,6 +77,12 @@ public class GVItemAndAttributeExpressionTests extends AbstractIntegrationTests
     @Autowired
     private EditLabelMutationRunner editLabelMutationRunner;
 
+    @Autowired
+    private DiagramComparator diagramComparator;
+
+    @Autowired
+    private DeleteFromDiagramRunner deleteFromDiagramRunner;
+
     private Step<DiagramRefreshedEventPayload> verifier;
 
     private AtomicReference<Diagram> diagram;
@@ -73,6 +91,8 @@ public class GVItemAndAttributeExpressionTests extends AbstractIntegrationTests
 
     private DirectEditTester directEditTester;
 
+    private DeleteFromDiagramTester deleteFromDiagramTester;
+
     @BeforeEach
     public void setUp() {
         this.givenInitialServerState.initialize();
@@ -84,6 +104,8 @@ public void setUp() {
         this.diagram = this.givenDiagram.getDiagram(this.verifier);
         this.directEditInitialLabelTester = new DirectEditInitialLabelTester(this.initialDirectEditElementLabelQueryRunner, GeneralViewItemAndAttributeProjectData.EDITING_CONTEXT_ID);
         this.directEditTester = new DirectEditTester(this.editLabelMutationRunner, GeneralViewItemAndAttributeProjectData.EDITING_CONTEXT_ID);
+        this.deleteFromDiagramTester = new DeleteFromDiagramTester(this.deleteFromDiagramRunner, GeneralViewItemAndAttributeProjectData.EDITING_CONTEXT_ID,
+                GeneralViewItemAndAttributeProjectData.GraphicalIds.DIAGRAM_ID);
     }
 
     @AfterEach
@@ -215,4 +237,92 @@ public void attributeWithBranketExpression() {
                 GeneralViewItemAndAttributeProjectData.GraphicalIds.P1_1_X1_ID,
                 "a2_1 = 45 [kilogram]");
     }
+
+    @DisplayName("GIVEN an ItemUsage, WHEN with a value referencing another ItemUsage, THEN an edge should connect the ItemUsage")
+    @Test
+    @Sql(scripts = { GeneralViewItemAndAttributeProjectData.SCRIPT_PATH }, executionPhase = Sql.ExecutionPhase.BEFORE_TEST_METHOD)
+    @Sql(scripts = { "/scripts/cleanup.sql" }, executionPhase = Sql.ExecutionPhase.AFTER_TEST_METHOD, config = @SqlConfig(transactionMode = SqlConfig.TransactionMode.ISOLATED))
+    public void itemFeatureChainBindingEdge() {
+
+        // Create an edge using direct edit
+        this.directEditTester.checkDirectEditInsideLabel(this.verifier, this.diagram,
+                GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_ICON_AND_LABEL_ID,
+                "in a2_1 = a1.a1_1",
+                this.buildEdgeChecker(GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_ICON_AND_LABEL_ID, "in a2_1 = a1.a1_1",
+                        GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_BORDERED_NODE_ID, GeneralViewItemAndAttributeProjectData.GraphicalIds.A1_1_BORDERED_NODE_ID));
+
+        // Change the edge to a new target
+        this.directEditTester.checkDirectEditInsideLabel(this.verifier, this.diagram,
+                GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_ICON_AND_LABEL_ID,
+                "in a2_1 = a1.a1_2",
+                this.buildEdgeChecker(GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_ICON_AND_LABEL_ID, "in a2_1 = a1.a1_2",
+                        GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_BORDERED_NODE_ID, GeneralViewItemAndAttributeProjectData.GraphicalIds.A1_2_BORDERED_NODE_ID));
+
+        // Remove edge
+        this.directEditTester.checkDirectEditInsideLabel(this.verifier, this.diagram,
+                GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_ICON_AND_LABEL_ID,
+                "in a2_1 =",
+                this.buildNoEdgeStartingFromChecker(GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_ICON_AND_LABEL_ID, "in a2_1",
+                        GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_1_BORDERED_NODE_ID));
+
+    }
+
+    @DisplayName("GIVEN an ItemUsage, WHEN deleting an edge representing a FeatureValue, THEN the FeatureValue should be deleted and the label of the ItemUsage should be updated updated")
+    @Test
+    @Sql(scripts = { GeneralViewItemAndAttributeProjectData.SCRIPT_PATH }, executionPhase = Sql.ExecutionPhase.BEFORE_TEST_METHOD)
+    @Sql(scripts = { "/scripts/cleanup.sql" }, executionPhase = Sql.ExecutionPhase.AFTER_TEST_METHOD, config = @SqlConfig(transactionMode = SqlConfig.TransactionMode.ISOLATED))
+    public void deleteFeatureValueEdge() {
+
+        this.deleteFromDiagramTester.checkRemoveFromDiagram(this.verifier, List.of(), List.of(GeneralViewItemAndAttributeProjectData.GraphicalIds.FEATURE_VALUE_A2_2_TO_A1_4_EDGE),
+                payload -> Optional.of(payload)
+                        .map(DiagramRefreshedEventPayload::diagram)
+                        .ifPresentOrElse(newDiagram -> {
+                            // Check label no more FeatureValue (the = part is gone)
+                            DiagramNavigator diagramNavigator = new DiagramNavigator(newDiagram);
+                            InsideLabel newLabel = diagramNavigator.nodeWithId(GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_2_ICON_AND_LABEL_ID).getNode().getInsideLabel();
+                            assertThat(newLabel.getText()).isEqualTo("out a2_2");
+
+                            // No more edge starting from a2_2
+                            assertThat(newDiagram.getEdges()).noneMatch(s -> GeneralViewItemAndAttributeProjectData.GraphicalIds.A2_2_BORDERED_NODE_ID.equals(s.getSourceId()));
+                        }, () -> fail("Missing diagram")));
+
+    }
+
+    private Consumer<DiagramRefreshedEventPayload> buildEdgeChecker(String nodeToCheckForLabel, String expectedLabel, String sourceNodeId, String targetNodeId) {
+        return payload -> Optional.of(payload)
+                .map(DiagramRefreshedEventPayload::diagram)
+                .ifPresentOrElse(newDiagram -> {
+                    // Check label
+                    DiagramNavigator diagramNavigator = new DiagramNavigator(newDiagram);
+                    InsideLabel newLabel = diagramNavigator.nodeWithId(nodeToCheckForLabel).getNode().getInsideLabel();
+                    assertThat(newLabel.getText()).isEqualTo(expectedLabel);
+
+                    // Check new edge
+                    List<Edge> newEdges = this.diagramComparator.newEdges(this.diagram.get(), newDiagram);
+                    assertThat(newEdges).hasSize(1)
+                            .first()
+                            .satisfies(edge -> {
+                                assertThat(edge.getSourceId()).as("Should start from A2_1").isEqualTo(sourceNodeId);
+                            }, edge -> {
+                                assertThat(edge.getTargetId()).as("Should end to A1_1").isEqualTo(targetNodeId);
+                            });
+                }, () -> fail("Missing diagram"));
+    }
+
+    private Consumer<DiagramRefreshedEventPayload> buildNoEdgeStartingFromChecker(String nodeToCheckForLabel, String expectedLabel, String sourceNodeId) {
+        return payload -> Optional.of(payload)
+                .map(DiagramRefreshedEventPayload::diagram)
+                .ifPresentOrElse(newDiagram -> {
+                    // Check label
+                    DiagramNavigator diagramNavigator = new DiagramNavigator(newDiagram);
+                    InsideLabel newLabel = diagramNavigator.nodeWithId(nodeToCheckForLabel).getNode().getInsideLabel();
+                    assertThat(newLabel.getText()).isEqualTo(expectedLabel);
+
+                    // Check there is starting from the given source
+                    List<Edge> newEdges = this.diagramComparator.newEdges(this.diagram.get(), newDiagram);
+
+                    assertThat(newDiagram.getEdges()).noneMatch(s -> sourceNodeId.equals(s.getSourceId()));
+                    assertThat(newEdges).hasSize(0);
+                }, () -> fail("Missing diagram"));
+    }
 }

backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/diagrams/testers/DeleteFromDiagramRunner.java

@@ -0,0 +1,70 @@
+/*******************************************************************************
+ * 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.application.controllers.diagrams.testers;
+
+import java.util.Objects;
+
+import org.eclipse.sirius.components.collaborative.diagrams.dto.DeleteFromDiagramInput;
+import org.eclipse.sirius.components.graphql.tests.api.IGraphQLRequestor;
+import org.eclipse.sirius.components.graphql.tests.api.IMutationRunner;
+import org.springframework.stereotype.Service;
+
+/**
+ * Used to invoke a remove from diagram tool with the GraphQL API.
+ *
+ * <p>
+ * This class should be provided by Sirius Web, remove this once
+ * https://github.com/eclipse-sirius/sirius-web/issues/5041 is closed
+ * </p>
+ *
+ * @author Arthur Daussy
+ */
+@Service
+public class DeleteFromDiagramRunner implements IMutationRunner<DeleteFromDiagramInput> {
+
+    private static final String REMOVE_FROM_DIAGRAM_MUTATION = """
+            mutation deleteFromDiagram($input: DeleteFromDiagramInput!) {
+              deleteFromDiagram(input: $input) {
+                __typename
+                ... on ErrorPayload {
+                  messages {
+                    body
+                    level
+                    __typename
+                  }
+                  __typename
+                }
+                ... on DeleteFromDiagramSuccessPayload {
+                  messages {
+                    body
+                    level
+                    __typename
+                  }
+                  __typename
+                }
+              }
+            }
+            """;
+
+    private final IGraphQLRequestor graphQLRequestor;
+
+    public DeleteFromDiagramRunner(IGraphQLRequestor graphQLRequestor) {
+        this.graphQLRequestor = Objects.requireNonNull(graphQLRequestor);
+    }
+
+    @Override
+    public String run(DeleteFromDiagramInput input) {
+        return this.graphQLRequestor.execute(REMOVE_FROM_DIAGRAM_MUTATION, input);
+    }
+
+}