code: private boolean notifyListenerRequestSend(HttpMessage httpMessage) {
  		ProxyListener listener = null;
  		List<ProxyListener> listenerList = parentServer.getListenerList();
  		for (int i=0;i<listenerList.size();i++) {
  			listener = listenerList.get(i);
  			try {
  			    if (! listener.onHttpRequestSend(httpMessage)) {
  			    	return false;
  			    }
  			} catch (Exception e) {
  				log.error("An error occurred while notifying listener:", e);
  			}
  		}
  		return true;
  	}
docs: Go through each observers to process a request in each observers.
  The method can be modified in each observers.
  @param httpMessage the request that was received from the client and may be forwarded to the server
  @return {@code true} if the message should be forwarded to the server, {@code false} otherwise