fixed empty property checking

Signed-off-by: Stefano Puri <stefano.puri@intecs.it>

plugins/mobius/org.polarsys.chess.mobius/transformations/CHESS2SAN.qvto

@@ -327,8 +327,11 @@ mapping UML::InstanceSpecification::UMLInstance2Join(isRootJoin : Boolean, y : I
 				result.addDoubleGlobalVariable('Num'.concat(rep.name), result);
 			};
 			
+			log("**************************11111111111111111111111111111111");
+			
 			//TODO: curently if a component has errorModel attached than it is considered terminal: we should also support internal components with error model
-			if (subInstance.isComposite() and  subInstance.getErrorModel()->oclIsUndefined()){
+			if (subInstance.isComposite() and  (subInstance.getErrorModel()->oclIsUndefined() or subInstance.getErrorModel() = null)){
+				log("**************************DDDDDDDDDDDDDDDDDDDDDDDDDDDDDD");
 				var childJoin : SAN::Join := subInstance.map UMLInstance2Join(false, y1+deltay);
 				if (not rep.oclIsUndefined()){
 					rep.child := childJoin;
@@ -1625,7 +1628,7 @@ query UML::InstanceSpecification::getSubInstances() : Set(UML::InstanceSpecifica
 	slots -> forEach(slot){
 		instances += slot.value.oclAsType(UML::InstanceValue).instance;
 	};
-	--log("subinstances = "+instances->size().toString());
+	log("subinstances of "+self.name+" = "+instances->size().toString());
 	return instances;
 }