/*

  * 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.giraph.comm;

 import java.io.IOException;

 import java.util.concurrent.ConcurrentMap;

 import org.apache.log4j.Logger;

 import org.jboss.netty.buffer.ChannelBuffer;

 import org.jboss.netty.buffer.ChannelBufferInputStream;

 import org.jboss.netty.channel.ChannelHandlerContext;

 import org.jboss.netty.channel.ChannelStateEvent;

 import org.jboss.netty.channel.ExceptionEvent;

 import org.jboss.netty.channel.MessageEvent;

 import org.jboss.netty.channel.SimpleChannelUpstreamHandler;

 /**

  * Generic handler of responses.

  */

 public class ResponseClientHandler extends SimpleChannelUpstreamHandler {

   /** Class logger */

   private static final Logger LOG =

       Logger.getLogger(ResponseClientHandler.class);

   /** Outstanding request map */

   private final ConcurrentMap<Long, RequestInfo> outstandingRequestMap;

   /**

    * Constructor.

    *

    * @param outstandingRequestMap Map of outstanding requests

    */

   public ResponseClientHandler(

       ConcurrentMap<Long, RequestInfo> outstandingRequestMap) {

     this.outstandingRequestMap = outstandingRequestMap;

   }

   @Override

   public void messageReceived(

       ChannelHandlerContext ctx, MessageEvent event) {

     if (!(event.getMessage() instanceof ChannelBuffer)) {

       throw new IllegalStateException("messageReceived: Got a " +

           "non-ChannelBuffer message " + event.getMessage());

     }

     ChannelBuffer buffer = (ChannelBuffer) event.getMessage();

     ChannelBufferInputStream inputStream = new ChannelBufferInputStream(buffer);

     long requestId = -1;

     int response = -1;

     try {

       requestId = inputStream.readLong();

       response = inputStream.readByte();

       inputStream.close();

     } catch (IOException e) {

       throw new IllegalStateException(

           "messageReceived: Got IOException ", e);

     }

     if (response != 0) {

       throw new IllegalStateException(

           "messageReceived: Got illegal response " + response);

     }

     RequestInfo requestInfo = outstandingRequestMap.remove(requestId);

     if (requestInfo == null) {

       throw new IllegalStateException("messageReceived: Impossible to " +

           "have a non-registered requestId " + requestId);

     } else {

       if (LOG.isDebugEnabled()) {

         LOG.debug("messageReceived: Processed request id = " + requestId +

             " " + requestInfo + ".  Waiting on " +

             outstandingRequestMap.size() +

             " requests, bytes = " + buffer.capacity());

       }

     }

     // Help NettyClient#waitSomeRequests() to finish faster

     synchronized (outstandingRequestMap) {

       outstandingRequestMap.notifyAll();

     }

   }

   @Override

   public void channelClosed(ChannelHandlerContext ctx,

                             ChannelStateEvent e) throws Exception {

     if (LOG.isDebugEnabled()) {

       LOG.debug("channelClosed: Closed the channel on " +

           ctx.getChannel().getRemoteAddress());

     }

   }

   @Override

   public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {

     throw new IllegalStateException("exceptionCaught: Channel failed with " +

         "remote address " + ctx.getChannel().getRemoteAddress(), e.getCause());

   }

 }