1 /* 2 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * - Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 11 * - Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * - Neither the name of Oracle nor the names of its 16 * contributors may be used to endorse or promote products derived 17 * from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * This source code is provided to illustrate the usage of a given feature 34 * or technique and has been deliberately simplified. Additional steps 35 * required for a production-quality application, such as security checks, 36 * input validation and proper error handling, might not be present in 37 * this sample code. 38 */ 39 40 41 import java.nio.channels.*; 42 import java.nio.charset.*; 43 import java.nio.ByteBuffer; 44 import java.net.*; 45 import java.io.IOException; 46 import java.util.*; 47 48 public class Reader { 49 usage()50 static void usage() { 51 System.err.println("usage: java Reader group:port@interf [-only source...] [-block source...]"); 52 System.exit(-1); 53 } 54 printDatagram(SocketAddress sa, ByteBuffer buf)55 static void printDatagram(SocketAddress sa, ByteBuffer buf) { 56 System.out.format("-- datagram from %s --\n", 57 ((InetSocketAddress)sa).getAddress().getHostAddress()); 58 System.out.println(Charset.defaultCharset().decode(buf)); 59 } 60 parseAddessList(String s, List<InetAddress> list)61 static void parseAddessList(String s, List<InetAddress> list) 62 throws UnknownHostException 63 { 64 String[] sources = s.split(","); 65 for (int i=0; i<sources.length; i++) { 66 list.add(InetAddress.getByName(sources[i])); 67 } 68 } 69 main(String[] args)70 public static void main(String[] args) throws IOException { 71 if (args.length == 0) 72 usage(); 73 74 // first parameter is the multicast address (interface required) 75 MulticastAddress target = MulticastAddress.parse(args[0]); 76 if (target.interf() == null) 77 usage(); 78 79 // addition arguments are source addresses to include or exclude 80 List<InetAddress> includeList = new ArrayList<InetAddress>(); 81 List<InetAddress> excludeList = new ArrayList<InetAddress>(); 82 int argc = 1; 83 while (argc < args.length) { 84 String option = args[argc++]; 85 if (argc >= args.length) 86 usage(); 87 String value = args[argc++]; 88 if (option.equals("-only")) { 89 parseAddessList(value, includeList); 90 continue; 91 } 92 if (option.equals("-block")) { 93 parseAddessList(value, excludeList); 94 continue; 95 } 96 usage(); 97 } 98 if (!includeList.isEmpty() && !excludeList.isEmpty()) { 99 usage(); 100 } 101 102 // create and bind socket 103 ProtocolFamily family = StandardProtocolFamily.INET; 104 if (target.group() instanceof Inet6Address) { 105 family = StandardProtocolFamily.INET6; 106 } 107 DatagramChannel dc = DatagramChannel.open(family) 108 .setOption(StandardSocketOptions.SO_REUSEADDR, true) 109 .bind(new InetSocketAddress(target.port())); 110 111 if (includeList.isEmpty()) { 112 // join group and block addresses on the exclude list 113 MembershipKey key = dc.join(target.group(), target.interf()); 114 for (InetAddress source: excludeList) { 115 key.block(source); 116 } 117 } else { 118 // join with source-specific membership for each source 119 for (InetAddress source: includeList) { 120 dc.join(target.group(), target.interf(), source); 121 } 122 } 123 124 // register socket with Selector 125 Selector sel = Selector.open(); 126 dc.configureBlocking(false); 127 dc.register(sel, SelectionKey.OP_READ); 128 129 // print out each datagram that we receive 130 ByteBuffer buf = ByteBuffer.allocateDirect(4096); 131 for (;;) { 132 int updated = sel.select(); 133 if (updated > 0) { 134 Iterator<SelectionKey> iter = sel.selectedKeys().iterator(); 135 while (iter.hasNext()) { 136 SelectionKey sk = iter.next(); 137 iter.remove(); 138 139 DatagramChannel ch = (DatagramChannel)sk.channel(); 140 SocketAddress sa = ch.receive(buf); 141 if (sa != null) { 142 buf.flip(); 143 printDatagram(sa, buf); 144 buf.rewind(); 145 buf.limit(buf.capacity()); 146 } 147 } 148 } 149 } 150 } 151 } 152