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    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the 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.qotm;
    17
    18  import java.net.InetSocketAddress;
    19  import java.util.concurrent.Executors;
    20
    21  import org.jboss.netty.bootstrap.ConnectionlessBootstrap;
    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.FixedReceiveBufferSizePredictorFactory;
    26  import org.jboss.netty.channel.socket.DatagramChannel;
    27  import org.jboss.netty.channel.socket.DatagramChannelFactory;
    28  import org.jboss.netty.channel.socket.nio.NioDatagramChannelFactory;
    29  import org.jboss.netty.handler.codec.string.StringDecoder;
    30  import org.jboss.netty.handler.codec.string.StringEncoder;
    31  import org.jboss.netty.util.CharsetUtil;
    32
    33  /**
    34   * A UDP broadcast client that asks for a quote of the moment (QOTM) to
    35   * {@link QuoteOfTheMomentServer}.
    36   *
    37   * Inspired by <a href="http://goo.gl/BsXVR">the official Java tutorial</a>.
    38   */
    39  public class QuoteOfTheMomentClient {
    40
    41      private final int port;
    42
    43      public QuoteOfTheMomentClient(int port) {
    44          this.port = port;
    45      }
    46
    47      public void run() {
    48          DatagramChannelFactory f =
    49              new NioDatagramChannelFactory(Executors.newCachedThreadPool());
    50
    51          ConnectionlessBootstrap b = new ConnectionlessBootstrap(f);
    52
    53          // Configure the pipeline factory.
    54          b.setPipelineFactory(new ChannelPipelineFactory() {
    55              public ChannelPipeline getPipeline() throws Exception {
    56                  return Channels.pipeline(
    57                          new StringEncoder(CharsetUtil.ISO_8859_1),
    58                          new StringDecoder(CharsetUtil.ISO_8859_1),
    59                          new QuoteOfTheMomentClientHandler());
    60              }
    61          });
    62
    63          // Enable broadcast
    64          b.setOption("broadcast", "true");
    65
    66          // Allow packets as large as up to 1024 bytes (default is 768).
    67          // You could increase or decrease this value to avoid truncated packets
    68          // or to improve memory footprint respectively.
    69          //
    70          // Please also note that a large UDP packet might be truncated or
    71          // dropped by your router no matter how you configured this option.
    72          // In UDP, a packet is truncated or dropped if it is larger than a
    73          // certain size, depending on router configuration.  IPv4 routers
    74          // truncate and IPv6 routers drop a large packet.  That's why it is
    75          // safe to send small packets in UDP.
    76          b.setOption(
    77                  "receiveBufferSizePredictorFactory",
    78                  new FixedReceiveBufferSizePredictorFactory(1024));
    79
    80          DatagramChannel c = (DatagramChannel) b.bind(new InetSocketAddress(0));
    81
    82          // Broadcast the QOTM request to port 8080.
    83          c.write("QOTM?", new InetSocketAddress("255.255.255.255", port));
    84
    85          // QuoteOfTheMomentClientHandler will close the DatagramChannel when a
    86          // response is received.  If the channel is not closed within 5 seconds,
    87          // print an error message and quit.
    88          if (!c.getCloseFuture().awaitUninterruptibly(5000)) {
    89              System.err.println("QOTM request timed out.");
    90              c.close().awaitUninterruptibly();
    91          }
    92
    93          f.releaseExternalResources();
    94      }
    95
    96      public static void main(String[] args) throws Exception {
    97          int port;
    98          if (args.length > 0) {
    99              port = Integer.parseInt(args[0]);
    100         } else {
    101             port = 8080;
    102         }
    103         new QuoteOfTheMomentClient(port).run();
    104     }
    105 }