code: public void addEvent(Event event) {
          if(event == null)
              throw new IllegalStateException("event must be non-null");
  
          if(logger.isTraceEnabled())
              logger.trace("Adding event " + event);
  
          eventQueue.add(event);
      }
docs: Add an event to the queue. It will be processed in the order received.
  
  @param event Event