content: /*
   * Copyright (c) 2013 - 2014, Allen A. George <allen dot george at gmail dot com>
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in the
   *       documentation and/or other materials provided with the distribution.
   *     * Neither the name of libraft nor the
   *       names of its contributors may be used to endorse or promote products
   *       derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package io.libraft.agent.rpc;
  
  import org.jboss.netty.channel.ChannelHandler;
  import org.jboss.netty.channel.ChannelHandlerContext;
  import org.jboss.netty.channel.ChannelStateEvent;
  import org.jboss.netty.channel.ExceptionEvent;
  import org.jboss.netty.channel.SimpleChannelHandler;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.net.ConnectException;
  
  /**
   * Stateless {@code ChannelHandler} that disconnects a
   * {@link org.jboss.netty.channel.Channel} if an exception is thrown
   * in its {@link org.jboss.netty.channel.ChannelPipeline}.
   */
  @ChannelHandler.Sharable
  final class FinalUpstreamHandler extends SimpleChannelHandler {
  
      private static final Logger LOGGER = LoggerFactory.getLogger(FinalUpstreamHandler.class);
      private final String self;
  
      /**
       * Constructor.
       *
       * @param self unique id of the Raft server that created this channel.
       *             This is <strong>not</strong> the unique id of the Raft server
       *             this channel is connected to.
       */
      public FinalUpstreamHandler(String self) {
          this.self = self;
      }
  
      @Override
      public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) { // discard event
      }
  
      @Override
      public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) { // discard event
      }
  
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
          Object attachment = e.getChannel().getAttachment();
          Throwable channelException = e.getCause();
  
          if (channelException instanceof ConnectException) {
              LOGGER.warn("{}: closing channel to {}: {}", self, attachment, channelException.getMessage());
          } else {
              LOGGER.warn("{}: caught exception - closing channel to {}", self, attachment, channelException);
          }
  
          e.getChannel().close();
      }
  }
  