throw new InferenceException("Cannot create a relationship in a null container, source or target");
// GMF 2.2: XXXCreateCommands no longer extend CreateElementCommand, so
// we must get the newly created element from the CreateElementRequest instead
CreateRelationshipRequest request = new CreateRelationshipRequest(getEditingDomain(), container, source, target, getDiagramEditType(elementType) );
EditElementCommand cc = getDiagramCreateRelationshipCommand(request, elementType, source, target );
if (cc == null) {
// we can't do anything because the diagram editor won't allow us to create it currently
//return null;
throw new InferenceException("Cannot create a relationship " + elementType + " in the editing domain " + getEditingDomain());
}