public void addEventSourceListener(EventSourceListener listener){
  LOG.entering(CLASS_NAME,"addEventSourceListener",listener);
  if (listener == null) {
    throw new NullPointerException("listener");
  }
  listeners.add(listener);
}

public void addEventSourceListener ( EventSourceListener listener ) { LOG . entering ( CLASS_NAME , "addEventSourceListener" , listener ) ; if ( listener == null ) { throw new NullPointerException ( "listener" ) ; } listeners . add ( listener ) ; }
register a listener for eventsource events
