public boolean addEventListener(IEventListener listener) {
        log.debug("addEventListener - scope: {} {}", getName(), listener);
        return listeners.add(listener);
    }
public boolean addEventListener ( IEventListener listener ) { log . debug ( "addEventListener - scope: {} {}" , getName ( ) , listener ) ; return listeners . add ( listener ) ; }
Add event listener to list of notified objects

@param listener Listening object
@return true if listener is added and false otherwise