ST6RI-793 Updated the derivation of TransitionUsage::source.

- Also revised the selection of the owned member used to determine the
transition source, to avoid selecting an initial MetadataUsage.

Author: seidewitz

org.omg.sysml/src/org/omg/sysml/delegate/setting/TransitionUsage_source_SettingDelegate.java

@@ -22,15 +22,13 @@
 
 package org.omg.sysml.delegate.setting;
 
-import org.eclipse.emf.common.util.EList;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.InternalEObject;
-import org.omg.sysml.lang.sysml.ActionUsage;
-import org.omg.sysml.lang.sysml.Element;
-import org.omg.sysml.lang.sysml.Membership;
+import org.omg.sysml.lang.sysml.Feature;
 import org.omg.sysml.lang.sysml.TransitionUsage;
-import org.omg.sysml.util.NamespaceUtil;
+import org.omg.sysml.util.FeatureUtil;
+import org.omg.sysml.util.UsageUtil;
 
 public class TransitionUsage_source_SettingDelegate extends BasicDerivedObjectSettingDelegate {
 
@@ -40,14 +38,8 @@ public TransitionUsage_source_SettingDelegate(EStructuralFeature eStructuralFeat
 
 	@Override
 	protected EObject basicGet(InternalEObject owner) {
-		NamespaceUtil.addAdditionalMembersTo((TransitionUsage)owner);
-		EList<Membership> ownedMemberships = ((TransitionUsage)owner).getOwnedMembership();
-		if (ownedMemberships.isEmpty()) {
-			return null;
-		} else {
-			Element member = ownedMemberships.get(0).getMemberElement();
-			return member instanceof ActionUsage? (ActionUsage)member: null;
-		}
+		Feature source = UsageUtil.getSourceFeatureOf((TransitionUsage)owner);
+		return source == null? null: FeatureUtil.getBasicFeatureOf(source);
 	}
 
 }

org.omg.sysml/src/org/omg/sysml/util/UsageUtil.java

@@ -199,7 +199,7 @@ public static Feature getSourceFeature(Feature feature) {
 		if (owningNamespace instanceof TransitionUsage) {
 			TransitionUsage transition = (TransitionUsage)owningNamespace;
 			if (transition.getSuccession() == feature) {
-				return transition.getSource();
+				return getSourceFeatureOf(transition);
 			}
 		}
 		return getPreviousFeature(feature);
@@ -377,6 +377,17 @@ private static boolean hasIncomingTransitionsIn(Type container, StateUsage state
 
 	// Transitions
 
+	public static Feature getSourceFeatureOf(TransitionUsage transition) {
+		NamespaceUtil.addAdditionalMembersTo(transition);
+		return transition.getOwnedMembership().stream().
+				filter(mem->!(mem instanceof FeatureMembership)).
+				map(Membership::getMemberElement).
+				filter(Feature.class::isInstance).
+				map(Feature.class::cast).
+				filter(f->FeatureUtil.getBasicFeatureOf(f) instanceof ActionUsage).
+				findFirst().orElse(null);
+	}
+	
 	public static Feature getTransitionSourceOf(Feature transition) {
 		Feature source= transition instanceof TransitionUsage? ((TransitionUsage)transition).getSource():
 			   transition instanceof Succession? ((Succession)transition).getSourceFeature():