content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.ambari.server.configuration.spring;
  
  import org.apache.ambari.server.agent.stomp.AgentsRegistrationQueue;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.messaging.Message;
  import org.springframework.messaging.MessageChannel;
  import org.springframework.messaging.simp.SimpMessageType;
  import org.springframework.messaging.simp.stomp.StompCommand;
  import org.springframework.messaging.simp.stomp.StompHeaderAccessor;
  import org.springframework.messaging.support.ChannelInterceptor;
  import org.springframework.messaging.support.MessageBuilder;
  
  public class AgentRegisteringQueueChecker implements ChannelInterceptor {
    private static final Logger LOG = LoggerFactory.getLogger(AgentsRegistrationQueue.class);
  
    @Autowired
    private AgentsRegistrationQueue agentsRegistrationQueue;
  
    @Override
    public Message<?> preSend(Message<?> message, MessageChannel channel) {
      StompHeaderAccessor headerAccessor= StompHeaderAccessor.wrap(message);
      String sessionId = headerAccessor.getSessionId();
  //    String sessionId = headerAccessor.getHeader("simpSessionId").toString();
      if (StompCommand.CONNECT.equals(headerAccessor.getCommand())
          && !agentsRegistrationQueue.offer(sessionId)) {
        StompHeaderAccessor headerAccessorError = StompHeaderAccessor.create(StompCommand.ERROR);
        headerAccessorError.setHeader("simpSessionId", sessionId);
        headerAccessorError.setHeader("simpConnectMessage", headerAccessor.getHeader("simpConnectMessage").toString());
        headerAccessorError.setMessage("Connection not allowed");
  
        return MessageBuilder.createMessage(new byte[0], headerAccessorError.getMessageHeaders());
      } else if (SimpMessageType.DISCONNECT_ACK.equals(headerAccessor.getMessageType())) {
        agentsRegistrationQueue.complete(sessionId);
      }
      return message;
    }
  }
  