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.ChannelHandler;
23 import org.jboss.netty.channel.ChannelPipeline;
24 import org.jboss.netty.channel.ChannelPipelineFactory;
25 import org.jboss.netty.channel.Channels;
26 import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
27 import org.jboss.netty.handler.timeout.ReadTimeoutHandler;
28 import org.jboss.netty.util.HashedWheelTimer;
29 import org.jboss.netty.util.Timer;
30
31
32 /**
33 * Connects to a server periodically to measure and print the uptime of the
34 * server. This example demonstrates how to implement reliable reconnection
35 * mechanism in Netty.
36 *
37 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
38 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
39 *
40 * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
41 */
42 public class UptimeClient {
43
44 // Sleep 5 seconds before a reconnection attempt.
45 static final int RECONNECT_DELAY = 5;
46
47 // Reconnect when the server sends nothing for 10 seconds.
48 private static final int READ_TIMEOUT = 10;
49
50 public static void main(String[] args) throws Exception {
51 // Print usage if no argument is specified.
52 if (args.length != 2) {
53 System.err.println(
54 "Usage: " + UptimeClient.class.getSimpleName() +
55 " <host> <port>");
56 return;
57 }
58
59 // Parse options.
60 String host = args[0];
61 int port = Integer.parseInt(args[1]);
62
63 // Initialize the timer that schedules subsequent reconnection attempts.
64 final Timer timer = new HashedWheelTimer();
65
66 // Configure the client.
67 final ClientBootstrap bootstrap = new ClientBootstrap(
68 new NioClientSocketChannelFactory(
69 Executors.newCachedThreadPool(),
70 Executors.newCachedThreadPool()));
71
72 // Configure the pipeline factory.
73 bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
74
75 private final ChannelHandler timeoutHandler =
76 new ReadTimeoutHandler(timer, READ_TIMEOUT);
77 private final ChannelHandler uptimeHandler =
78 new UptimeClientHandler(bootstrap, timer);
79
80 public ChannelPipeline getPipeline() throws Exception {
81 return Channels.pipeline(
82 timeoutHandler, uptimeHandler);
83 }
84 });
85
86 bootstrap.setOption(
87 "remoteAddress", new InetSocketAddress(host, port));
88
89 // Initiate the first connection attempt - the rest is handled by
90 // UptimeClientHandler.
91 bootstrap.connect();
92 }
93 }