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 * https://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 io.netty.example.qotm;
17
18 import io.netty.bootstrap.Bootstrap;
19 import io.netty.buffer.Unpooled;
20 import io.netty.channel.Channel;
21 import io.netty.channel.ChannelOption;
22 import io.netty.channel.EventLoopGroup;
23 import io.netty.channel.MultiThreadIoEventLoopGroup;
24 import io.netty.channel.nio.NioIoHandler;
25 import io.netty.channel.socket.DatagramPacket;
26 import io.netty.channel.socket.nio.NioDatagramChannel;
27 import io.netty.util.CharsetUtil;
28 import io.netty.util.internal.SocketUtils;
29
30 /**
31 * A UDP broadcast client that asks for a quote of the moment (QOTM) to {@link QuoteOfTheMomentServer}.
32 *
33 * Inspired by <a href="https://docs.oracle.com/javase/tutorial/networking/datagrams/clientServer.html">the official
34 * Java tutorial</a>.
35 */
36 public final class QuoteOfTheMomentClient {
37
38 static final int PORT = Integer.parseInt(System.getProperty("port", "7686"));
39
40 public static void main(String[] args) throws Exception {
41
42 EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
43 try {
44 Bootstrap b = new Bootstrap();
45 b.group(group)
46 .channel(NioDatagramChannel.class)
47 .option(ChannelOption.SO_BROADCAST, true)
48 .handler(new QuoteOfTheMomentClientHandler());
49
50 Channel ch = b.bind(0).sync().channel();
51
52 // Broadcast the QOTM request to port 8080.
53 ch.writeAndFlush(new DatagramPacket(
54 Unpooled.copiedBuffer("QOTM?", CharsetUtil.UTF_8),
55 SocketUtils.socketAddress("255.255.255.255", PORT))).sync();
56
57 // QuoteOfTheMomentClientHandler will close the DatagramChannel when a
58 // response is received. If the channel is not closed within 5 seconds,
59 // print an error message and quit.
60 if (!ch.closeFuture().await(5000)) {
61 System.err.println("QOTM request timed out.");
62 }
63 } finally {
64 group.shutdownGracefully();
65 }
66 }
67 }