code: public void processEvent(EventObject event) {
      if (event instanceof RequestEvent) {
        processRequest((RequestEvent) event);
      } else if (event instanceof ResponseEvent) {
        processResponse((ResponseEvent) event);
      } else if (event instanceof TimeoutEvent) {
        processTimeout((TimeoutEvent) event);
      } else {
        LOG.error("invalid event type received: {}: {}", event.getClass().getName(), event.toString());
      }
    }
docs: /*
  @see org.cafesip.sipunit.MessageListener#processEvent(java.util.EventObject)