call properti chang own element model provid implement link vetoabl chang listen properti veto except wish allow chang roll don param pce event trigger extract properti trigger vetoabl chang properti chang event pce interest own element properti ad namespac model remov old valu properti collect own element valu element describ model element model remov own element equal pce properti list old own list pce old valu object eo element pce valu object model facad model element eo element old own mean remov make sure associ model element remov old own contain eo defin log lp log local nest statement lp log granular type statement lp log local nest ifdef usecasediagram log debug model remov endif remov node model facad actor model facad us remov node model facad associ model facad gener model facad extend model facad includ model facad depend remov edg remov edg defin log lp log granular type statement lp log local nest statement lp log local nest ifdef usecasediagram ad worri log debug model ad endif 