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1   /*
2    * Copyright 2009 Red Hat, Inc.
3    *
4    * Red Hat licenses this file to you under the Apache License, version 2.0
5    * (the "License"); you may not use this file except in compliance with the
6    * License.  You may obtain a copy of the License at:
7    *
8    *    http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package org.jboss.netty.example.uptime;
17  
18  import java.net.InetSocketAddress;
19  import java.util.concurrent.Executors;
20  
21  import org.jboss.netty.bootstrap.ClientBootstrap;
22  import org.jboss.netty.channel.ChannelPipeline;
23  import org.jboss.netty.channel.ChannelPipelineFactory;
24  import org.jboss.netty.channel.Channels;
25  import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
26  import org.jboss.netty.handler.timeout.ReadTimeoutHandler;
27  import org.jboss.netty.util.HashedWheelTimer;
28  import org.jboss.netty.util.Timer;
29  
30  
31  /**
32   * Connects to a server periodically to measure and print the uptime of the
33   * server.  This example demonstrates how to implement reliable reconnection
34   * mechanism in Netty.
35   *
36   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
37   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
38   *
39   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
40   */
41  public class UptimeClient {
42  
43      // Sleep 5 seconds before a reconnection attempt.
44      static final int RECONNECT_DELAY = 5;
45  
46      // Reconnect when the server sends nothing for 10 seconds.
47      private static final int READ_TIMEOUT = 10;
48  
49      public static void main(String[] args) throws Exception {
50          // Print usage if no argument is specified.
51          if (args.length != 2) {
52              System.err.println(
53                      "Usage: " + UptimeClient.class.getSimpleName() +
54                      " <host> <port>");
55              return;
56          }
57  
58          // Parse options.
59          String host = args[0];
60          int port = Integer.parseInt(args[1]);
61  
62          // Initialize the timer that schedules subsequent reconnection attempts.
63          final Timer timer = new HashedWheelTimer();
64  
65          // Configure the client.
66          final ClientBootstrap bootstrap = new ClientBootstrap(
67                  new NioClientSocketChannelFactory(
68                          Executors.newCachedThreadPool(),
69                          Executors.newCachedThreadPool()));
70  
71          // Configure the pipeline factory.
72          bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
73              public ChannelPipeline getPipeline() throws Exception {
74                  return Channels.pipeline(
75                          new ReadTimeoutHandler(timer, READ_TIMEOUT),
76                          new UptimeClientHandler(bootstrap, timer));
77              }
78          });
79  
80          bootstrap.setOption(
81                  "remoteAddress", new InetSocketAddress(host, port));
82  
83          // Initiate the first connection attempt - the rest is handled by
84          // UptimeClientHandler.
85          bootstrap.connect();
86      }
87  }