question: @ SuppressWarnings ( "unchecked" ) protected void notifyPropertyChangeListener ( String property , Object oldValue , Object newValue ) { if ( ( oldValue != null && oldValue . equals ( newValue ) ) || oldValue == newValue ) { log . error ( "notifyPropertyChangeListener without change" ) ; } Vector < PropertyChangeListener > v ; synchronized ( this ) { v = ( Vector < PropertyChangeListener > ) listeners . clone ( ) ; } if ( log . isDebugEnabled ( ) ) { log . debug ( "notify " + v . size ( ) + " listeners about property " + property ) ; } int cnt = v . size ( ) ; for ( int i = 0 ; i < cnt ; i ++ ) { PropertyChangeListener client = v . elementAt ( i ) ; client . propertyChange ( new PropertyChangeEvent ( this , property , oldValue , newValue ) ) ; } }
target:  Trigger the notification of all PropertyChangeListeners