initialis listen properti chang listen listen object uml messag add element listen listen uml messag activ predecessor successor sender receiv action object action model facad action uml messag action add element listen listen action remov recurr script actual argument signal oper list model facad actual argument action object argument add element listen listen argument remov valu model facad action action object oper model facad oper action model facad oper oper add element listen listen oper model facad send action action object signal model facad signal action model facad signal signal add element listen listen signal 