code: public boolean addLinguServiceEventListener(XLinguServiceEventListener xLinEvLis) {
  
  		boolean ret = false;
  		if (xLinEvLis == null) {
  			ret = false;
  		} else {
  			xEventListeners.add(xLinEvLis);
  			ret = true;
  		}
  
  		return ret;
      }
docs: /*>> XLinguServiceEventBroadcaster