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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.telnet;
17  
18  import java.io.BufferedReader;
19  import java.io.InputStreamReader;
20  import java.net.InetSocketAddress;
21  import java.util.concurrent.Executors;
22  
23  import org.jboss.netty.bootstrap.ClientBootstrap;
24  import org.jboss.netty.channel.Channel;
25  import org.jboss.netty.channel.ChannelFuture;
26  import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
27  
28  /**
29   * Simplistic telnet client.
30   *
31   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
32   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
33   *
34   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
35   */
36  public class TelnetClient {
37  
38      public static void main(String[] args) throws Exception {
39          // Print usage if no argument is specified.
40          if (args.length != 2) {
41              System.err.println(
42                      "Usage: " + TelnetClient.class.getSimpleName() +
43                      " <host> <port>");
44              return;
45          }
46  
47          // Parse options.
48          String host = args[0];
49          int port = Integer.parseInt(args[1]);
50  
51          // Configure the client.
52          ClientBootstrap bootstrap = new ClientBootstrap(
53                  new NioClientSocketChannelFactory(
54                          Executors.newCachedThreadPool(),
55                          Executors.newCachedThreadPool()));
56  
57          // Configure the pipeline factory.
58          bootstrap.setPipelineFactory(new TelnetClientPipelineFactory());
59  
60          // Start the connection attempt.
61          ChannelFuture future = bootstrap.connect(new InetSocketAddress(host, port));
62  
63          // Wait until the connection attempt succeeds or fails.
64          Channel channel = future.awaitUninterruptibly().getChannel();
65          if (!future.isSuccess()) {
66              future.getCause().printStackTrace();
67              bootstrap.releaseExternalResources();
68              return;
69          }
70  
71          // Read commands from the stdin.
72          ChannelFuture lastWriteFuture = null;
73          BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
74          for (;;) {
75              String line = in.readLine();
76              if (line == null) {
77                  break;
78              }
79  
80              // Sends the received line to the server.
81              lastWriteFuture = channel.write(line + "\r\n");
82  
83              // If user typed the 'bye' command, wait until the server closes
84              // the connection.
85              if (line.toLowerCase().equals("bye")) {
86                  channel.getCloseFuture().awaitUninterruptibly();
87                  break;
88              }
89          }
90  
91          // Wait until all messages are flushed before closing the channel.
92          if (lastWriteFuture != null) {
93              lastWriteFuture.awaitUninterruptibly();
94          }
95  
96          // Close the connection.  Make sure the close operation ends because
97          // all I/O operations are asynchronous in Netty.
98          channel.close().awaitUninterruptibly();
99  
100         // Shut down all thread pools to exit.
101         bootstrap.releaseExternalResources();
102     }
103 }