protected String getClientInfo() {
   String clientInfo = "Session n/a";
   if (session != null) {
     clientInfo = session.getClientInfo();
   }
   return clientInfo;
 }
 protected void handleWillMessage() {
   //        Container.logger().info("handle will message... ");
   if (session != null) {
     //            Container.logger().info("handle will message: session found!");
     session.handleWillMessage();
   }
   //        Container.logger().info("handle will message end.");
 }
 public void shutdown() {
   if (tokenizer != null) {
     tokenizer.removeAllListeners();
     tokenizer = null;
   }
   if (session != null) {
     session.shutdown();
     session = null;
   }
   vertx = null;
 }
  private void onMessageFromClient(AbstractMessage msg) throws Exception {
    Container.logger().debug("<<< " + msg);
    switch (msg.getMessageType()) {
      case CONNECT:
        ConnectMessage connect = (ConnectMessage) msg;
        ConnAckMessage connAck = new ConnAckMessage();
        if (session == null) {
          session = new MQTTSession(vertx, config);
          session.setPublishMessageHandler(this::sendMessageToClient);
          session.setKeepaliveErrorHandler(
              clientID -> {
                String cinfo = clientID;
                if (session != null) {
                  cinfo = session.getClientInfo();
                }
                Container.logger()
                    .info("keep alive exausted! closing connection for client[" + cinfo + "] ...");
                closeConnection();
              });
          connAck.setSessionPresent(false);
        } else {
          Container.logger().warn("Session alredy allocated ...");
          /*
          The Server MUST process a second CONNECT Packet sent from a Client as a protocol violation and disconnect the Client
           */
          //                    connAck.setSessionPresent(true);// TODO implement cleanSession=false
          closeConnection();
          break;
        }
        session.handleConnectMessage(
            connect,
            authenticated -> {
              if (authenticated) {
                connAck.setReturnCode(ConnAckMessage.CONNECTION_ACCEPTED);
                sendMessageToClient(connAck);
              } else {
                Container.logger()
                    .error(
                        "Authentication failed! clientID= "
                            + connect.getClientID()
                            + " username="******"type of message not known: " + msg.getClass().getSimpleName());
        break;
    }

    // TODO: forward mqtt message to backup server

  }
 private void handleDisconnect(DisconnectMessage disconnectMessage) {
   session.handleDisconnect(disconnectMessage);
   session = null;
 }