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   /*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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.jboss.netty.example.uptime;
  
  import org.jboss.netty.bootstrap.ClientBootstrap;
  import org.jboss.netty.channel.ChannelHandlerContext;
  import org.jboss.netty.channel.ChannelStateEvent;
  import org.jboss.netty.channel.ExceptionEvent;
  import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
  import org.jboss.netty.handler.timeout.ReadTimeoutException;
  import org.jboss.netty.util.Timeout;
  import org.jboss.netty.util.Timer;
  import org.jboss.netty.util.TimerTask;
  
  import java.net.ConnectException;
  import java.net.InetSocketAddress;
  import java.util.concurrent.TimeUnit;
  
  /**
   * Keep reconnecting to the server while printing out the current uptime and
   * connection attempt status.
   */
  public class UptimeClientHandler extends SimpleChannelUpstreamHandler {
  
      final ClientBootstrap bootstrap;
      private final Timer timer;
      private long startTime = -1;
  
      public UptimeClientHandler(ClientBootstrap bootstrap, Timer timer) {
          this.bootstrap = bootstrap;
          this.timer = timer;
      }
  
      InetSocketAddress getRemoteAddress() {
          return (InetSocketAddress) bootstrap.getOption("remoteAddress");
      }
  
      @Override
      public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
          println("Disconnected from: " + getRemoteAddress());
      }
  
      @Override
      public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) {
          println("Sleeping for: " + UptimeClient.RECONNECT_DELAY + 's');
          timer.newTimeout(new TimerTask() {
              public void run(Timeout timeout) {
                  println("Reconnecting to: " + getRemoteAddress());
                  bootstrap.connect();
              }
          }, UptimeClient.RECONNECT_DELAY, TimeUnit.SECONDS);
      }
  
      @Override
      public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
          if (startTime < 0) {
              startTime = System.currentTimeMillis();
          }
  
          println("Connected to: " + getRemoteAddress());
      }
  
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
          Throwable cause = e.getCause();
          if (cause instanceof ConnectException) {
              startTime = -1;
              println("Failed to connect: " + cause.getMessage());
          }
          if (cause instanceof ReadTimeoutException) {
              // The connection was OK but there was no traffic for last period.
              println("Disconnecting due to no inbound traffic");
          } else {
              cause.printStackTrace();
          }
          ctx.getChannel().close();
      }
  
      private void println(String msg) {
          if (startTime < 0) {
              System.err.format("[SERVER IS DOWN] %s%n", msg);
          } else {
              System.err.format("[UPTIME: %5ds] %s%n", (System.currentTimeMillis() - startTime) / 1000, msg);
          }
      }
  }