overrid initialis listen properti chang listen listen object model element add element listen listen model element model facad oper model element stereotyp object uml model facad stereotyp model element add element listen listen uml paramet object uml model facad paramet model element add element listen listen uml type chang object type model facad type uml type add element listen listen type tag valu object uml model facad tag valu collect model element add element listen listen uml 