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