eclipse-syson · pcdavid · Mar 3, 2026
diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
@@ -12,6 +12,8 @@
 
 === Improvements
 
+- https://github.com/eclipse-syson/syson/issues/1583[#1583] [diagrams] Improve support for `Stakeholder`.
+
 === New features
 
 

diff --git a/...yson/application/controllers/diagrams/general/view/GVSubNodeRequirementCreationTests.java b/...yson/application/controllers/diagrams/general/view/GVSubNodeRequirementCreationTests.java
@@ -1107,7 +1107,8 @@ private void createNewStakeholderIn(EClass eClassWithStakeholderParameter, Strin
         Consumer<Object> diagramCheck = assertRefreshedDiagramThat(newDiagram -> {
             var initialDiagram = diagram.get();
             new CheckDiagramElementCount(this.diagramComparator)
-                    .hasNewNodeCount(1)
+                    .hasNewNodeCount(9)
+                    .hasNewEdgeCount(1)
                     .check(initialDiagram, newDiagram);
             new CheckNodeInCompartment(diagramDescriptionIdProvider, this.diagramComparator)
                     .withParentLabel(parentNodeLabel)

diff --git a/...sysml-metamodel/src/main/java/org/eclipse/syson/sysml/impl/StakeholderMembershipImpl.java b/...sysml-metamodel/src/main/java/org/eclipse/syson/sysml/impl/StakeholderMembershipImpl.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright (c) 2023, 2025 Obeo.
+* Copyright (c) 2023, 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
@@ -66,13 +66,14 @@ public PartUsage getOwnedStakeholderParameter() {
     /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
      *
-     * @generated
+     * @generated NOT
      */
     public PartUsage basicGetOwnedStakeholderParameter() {
-        // TODO: implement this method to return the 'Owned Stakeholder Parameter' reference
-        // -> do not perform proxy resolution
-        // Ensure that you remove @generated or mark it @generated NOT
-        return null;
+        return this.getOwnedRelatedElement().stream()
+                .filter(PartUsage.class::isInstance)
+                .map(PartUsage.class::cast)
+                .findFirst()
+                .orElse(null);
     }
 
     /**

diff --git a/...l-metamodel/src/test/java/org/eclipse/syson/sysml/impl/RequirementDefinitionImplTest.java b/...l-metamodel/src/test/java/org/eclipse/syson/sysml/impl/RequirementDefinitionImplTest.java
@@ -12,6 +12,7 @@
  *******************************************************************************/
 package org.eclipse.syson.sysml.impl;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.List;
@@ -21,6 +22,7 @@
 import org.eclipse.syson.sysml.PartUsage;
 import org.eclipse.syson.sysml.RequirementDefinition;
 import org.eclipse.syson.sysml.StakeholderMembership;
+import org.eclipse.syson.sysml.SubjectMembership;
 import org.eclipse.syson.sysml.SysmlFactory;
 import org.eclipse.syson.sysml.SysmlPackage;
 import org.junit.jupiter.api.Assertions;
@@ -61,16 +63,35 @@ public static void setUpRequirementDefinition() {
 
     @Test
     public void testGetActorParameter() {
+        // Check that we can find the actors from the Requirement
         final List<PartUsage> actorParameterValue = REQUIREMENT_DEFINITION.getActorParameter();
         Assertions.assertNotNull(actorParameterValue);
         Assertions.assertIterableEquals(ACTOR_PART_USAGES, actorParameterValue);
+
+        // Also check that we can get them directly from the ActorMembership themselves
+        List<PartUsage> actors = REQUIREMENT_DEFINITION.getOwnedMembership().stream()
+                .filter(ActorMembership.class::isInstance)
+                .map(ActorMembership.class::cast)
+                .map(ActorMembership::getOwnedActorParameter)
+                .toList();
+        Assertions.assertIterableEquals(ACTOR_PART_USAGES, actors);
     }
 
     @Test
     public void testGetStakeholderParameter() {
+        // Check that we can find the stakeholders from the Requirement
         final List<PartUsage> stakeholderParameterValue = REQUIREMENT_DEFINITION.getStakeholderParameter();
         Assertions.assertNotNull(stakeholderParameterValue);
         Assertions.assertIterableEquals(STAKEHOLDER_PART_USAGES, stakeholderParameterValue);
+
+        // Also check that we can get them directly from the StakeholderMembership themselves
+        List<PartUsage> stakeholders = REQUIREMENT_DEFINITION.getOwnedMembership().stream()
+                .filter(StakeholderMembership.class::isInstance)
+                .map(StakeholderMembership.class::cast)
+                .map(StakeholderMembership::getOwnedStakeholderParameter)
+                .toList();
+        Assertions.assertIterableEquals(STAKEHOLDER_PART_USAGES, stakeholders);
+        assertThat(stakeholders).hasSameElementsAs(STAKEHOLDER_PART_USAGES);
     }
 
     @Test

diff --git a/...services/src/main/java/org/eclipse/syson/diagram/services/DiagramQueryElementService.java b/...services/src/main/java/org/eclipse/syson/diagram/services/DiagramQueryElementService.java
@@ -305,6 +305,11 @@ public Optional<String> getNodeDescriptionId(Element element, Diagram diagram, I
                         .filter(nodeDesc -> nodeDesc.getName().equals("GV Node " + SysmlPackage.eINSTANCE.getPackage().getName()))
                         .map(nodeDesc -> this.diagramIdProvider.getId(nodeDesc))
                         .findFirst();
+            } else if (this.metamodelQueryElementService.isStakeholder(element)) {
+                nodeDescriptionId = EMFUtils.allContainedObjectOfType(optViewDD.get(), org.eclipse.sirius.components.view.diagram.NodeDescription.class)
+                        .filter(nodeDesc -> nodeDesc.getName().equals("GV Node Stakeholder"))
+                        .map(nodeDesc -> this.diagramIdProvider.getId(nodeDesc))
+                        .findFirst();
             } else {
                 nodeDescriptionId = EMFUtils.allContainedObjectOfType(optViewDD.get(), org.eclipse.sirius.components.view.diagram.NodeDescription.class)
                         .filter(nodeDesc -> nodeDesc.getName().equals("GV Node " + element.eClass().getName()))

diff --git a/...del-services/src/main/java/org/eclipse/syson/model/services/aql/ModelQueryAQLService.java b/...del-services/src/main/java/org/eclipse/syson/model/services/aql/ModelQueryAQLService.java
@@ -41,6 +41,13 @@ public boolean isActor(Element element) {
         return this.metamodelQueryElementService.isActor(element);
     }
 
+    /**
+     * {@link MetamodelQueryElementService#isStakeholder(Element)}.
+     */
+    public boolean isStakeholder(Element element) {
+        return this.metamodelQueryElementService.isStakeholder(element);
+    }
+
     /**
      * {@link MetamodelQueryElementService#isSubject(Element)}.
      */

diff --git a/...rc/main/java/org/eclipse/syson/sysml/metamodel/services/MetamodelQueryElementService.java b/...rc/main/java/org/eclipse/syson/sysml/metamodel/services/MetamodelQueryElementService.java
@@ -26,6 +26,7 @@
 import org.eclipse.syson.sysml.FeatureValue;
 import org.eclipse.syson.sysml.PartUsage;
 import org.eclipse.syson.sysml.ReferenceUsage;
+import org.eclipse.syson.sysml.StakeholderMembership;
 import org.eclipse.syson.sysml.SubjectMembership;
 
 /**
@@ -63,6 +64,20 @@ public boolean isSubject(Element element) {
         return element instanceof ReferenceUsage && element.getOwningMembership() instanceof SubjectMembership;
     }
 
+    /**
+     * Return {@code true} if the provided {@code element} is a stakeholder, {@code false} otherwise.
+     * <p>
+     * A stakeholder is a kind of parameter stored in an {@link StakeholderMembership}.
+     * </p>
+     *
+     * @param element
+     *            the element to check
+     * @return {@code true} if the provided {@code element} is an stakeholder, {@code false} otherwise
+     */
+    public boolean isStakeholder(Element element) {
+        return element instanceof PartUsage && element.getOwningMembership() instanceof StakeholderMembership;
+    }
+
     /**
      * Get the source of a {@link Connector}.
      *

diff --git a/...ava/org/eclipse/syson/diagram/common/view/nodes/AbstractUsageNodeDescriptionProvider.java b/...ava/org/eclipse/syson/diagram/common/view/nodes/AbstractUsageNodeDescriptionProvider.java
@@ -48,6 +48,7 @@
 import org.eclipse.syson.diagram.services.aql.DiagramQueryAQLService;
 import org.eclipse.syson.services.DeleteService;
 import org.eclipse.syson.services.UtilService;
+import org.eclipse.syson.util.AQLConstants;
 import org.eclipse.syson.util.IDescriptionNameGenerator;
 import org.eclipse.syson.util.ServiceMethod;
 import org.eclipse.syson.util.SysMLMetamodelHelper;
@@ -168,6 +169,7 @@ public NodeDescription create() {
                 .collapsible(true)
                 .defaultHeightExpression(defaultSizeExpression.defaultHeightExpression())
                 .defaultWidthExpression(defaultSizeExpression.defaultWidthExpression())
+                .isHiddenByDefaultExpression(this.getHiddenByDefaultExpression())
                 .domainType(domainType)
                 .insideLabel(this.createInsideLabelDescription())
                 .outsideLabels(this.createOutsideLabelDescriptions().toArray(OutsideLabelDescription[]::new))
@@ -202,6 +204,10 @@ public void link(DiagramDescription diagramDescription, IViewDiagramElementFinde
         });
     }
 
+    protected String getHiddenByDefaultExpression() {
+        return AQLConstants.AQL_FALSE;
+    }
+
     protected InsideLabelDescription createInsideLabelDescription() {
         return this.diagramBuilderHelper.newInsideLabelDescription()
                 .labelExpression(ServiceMethod.of0(DiagramQueryAQLService::getContainerLabel).aqlSelf())

diff --git a/...on-view/src/main/java/org/eclipse/syson/diagram/common/view/services/ViewNodeService.java b/...on-view/src/main/java/org/eclipse/syson/diagram/common/view/services/ViewNodeService.java
@@ -408,6 +408,30 @@ public List<PartUsage> getExposedActors(Element element, EClass domainType, List
                 .toList();
     }
 
+    /**
+     * Get all Stakeholder ({@link PartUsage}) in {@link ViewUsage}'s exposed elements.
+     *
+     * @param element
+     *            the {@link Element} for which we want the Stakeholders.
+     * @param domainType
+     *            the domain type to the elements to retrieve
+     * @param ancestors
+     *            the given ancestors (semantic elements of the graphical nodes that are the ancestors) of the Node on
+     *            which this service has been called.
+     * @param editingContext
+     *            the given {@link IEditingContext} in which this service has been called.
+     * @param diagramContext
+     *            the given {@link DiagramContext} in which this service has been called.
+     * @return the list of Actor {@link PartUsage}s in {@link ViewUsage}'s exposed elements.
+     */
+    public List<PartUsage> getExposedStakeholders(Element element, EClass domainType, List<Object> ancestors, IEditingContext editingContext, DiagramContext diagramContext) {
+        return this.getExposedElements(element, domainType, ancestors, editingContext, diagramContext).stream()
+                .filter(PartUsage.class::isInstance)
+                .map(PartUsage.class::cast)
+                .filter(this.metamodelQueryElementService::isStakeholder)
+                .toList();
+    }
+
     /**
      * Get all Subjects ({@link ReferenceUsage}) in {@link ViewUsage}'s exposed elements.
      *

diff --git a/...on-view/src/main/java/org/eclipse/syson/diagram/common/view/services/ViewToolService.java b/...on-view/src/main/java/org/eclipse/syson/diagram/common/view/services/ViewToolService.java
@@ -58,6 +58,7 @@
 import org.eclipse.syson.sysml.PartUsage;
 import org.eclipse.syson.sysml.RequirementDefinition;
 import org.eclipse.syson.sysml.RequirementUsage;
+import org.eclipse.syson.sysml.StakeholderMembership;
 import org.eclipse.syson.sysml.StateDefinition;
 import org.eclipse.syson.sysml.StateUsage;
 import org.eclipse.syson.sysml.SubjectMembership;
@@ -236,6 +237,38 @@ public Element reconnectSourceNestedActorEdge(Element self, Element newSource, E
         return otherEnd;
     }
 
+    /**
+     * Reconnects the source of a nested stakeholder edge.
+     * <p>
+     * The source of this edge is a Requirement, and can only be reconnected to Requirements.
+     * </p>
+     *
+     * @param self
+     *            the current Requirement
+     * @param newSource
+     *            the new Requirement
+     * @param otherEnd
+     *            the Stakeholder connected to the Requirement
+     * @return the Stakeholder
+     */
+    public Element reconnectSourceNestedStakeholderEdge(Element self, Element newSource, Element otherEnd) {
+        if (newSource instanceof RequirementUsage || newSource instanceof RequirementDefinition) {
+            if (otherEnd.getOwningMembership() instanceof StakeholderMembership stakeholderMembership) {
+                newSource.getOwnedRelationship().add(stakeholderMembership);
+            } else {
+                // This is an error, an Stakeholder should always be contained in an StakeholderMembership.
+                String errorMessage = "Cannot reconnect the Stakeholder, it is not owned by an " + StakeholderMembership.class.getSimpleName();
+                this.logger.error(errorMessage);
+                this.feedbackMessageService.addFeedbackMessage(new Message(errorMessage, MessageLevel.ERROR));
+            }
+        } else {
+            String errorMessage = "Cannot reconnect an Stakeholder to non-Requirement element";
+            this.logger.warn(errorMessage);
+            this.feedbackMessageService.addFeedbackMessage(new Message(errorMessage, MessageLevel.WARNING));
+        }
+        return otherEnd;
+    }
+
     /**
      * Reconnects the source of a nested subject edge.
      * <p>
Original file line number	Diff line number	Diff line change
Expand Up		@@ -12,6 +12,8 @@

		=== Improvements

		- https://github.com/eclipse-syson/syson/issues/1583[#1583] [diagrams] Improve support for `Stakeholder`.

		=== New features


Expand Down