helper method chang connect node todo probabl superclass associ diagram type rerout associ object node object old node object edg sourc check param type connect legal uml connect model facad classifi node model facad classifi old node connect interfac end type object node sourc node model core helper destin edg node model core helper sourc edg model facad node model facad node cast param object edg assoc edg object end object end collect connect model facad connect edg assoc iter iter connect iter sourc rerout sourc end iter end iter rerout destin end iter end iter set end type model core helper set type end node 