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/*
* Copyright (c) 2007, 2008, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Oracle nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This source code is provided to illustrate the usage of a given feature
* or technique and has been deliberately simplified. Additional steps
* required for a production-quality application, such as security checks,
* input validation and proper error handling, might not be present in
* this sample code.
*/
import java.nio.channels.*;
import java.nio.charset.*;
import java.nio.ByteBuffer;
import java.net.*;
import java.io.IOException;
import java.util.*;
public class Reader {
static void usage() {
System.err.println("usage: java Reader group:port@interf [-only source...] [-block source...]");
System.exit(-1);
}
static void printDatagram(SocketAddress sa, ByteBuffer buf) {
System.out.format("-- datagram from %s --\n",
((InetSocketAddress)sa).getAddress().getHostAddress());
System.out.println(Charset.defaultCharset().decode(buf));
}
static void parseAddessList(String s, List<InetAddress> list)
throws UnknownHostException
{
String[] sources = s.split(",");
for (int i=0; i<sources.length; i++) {
list.add(InetAddress.getByName(sources[i]));
}
}
public static void main(String[] args) throws IOException {
if (args.length == 0)
usage();
// first parameter is the multicast address (interface required)
MulticastAddress target = MulticastAddress.parse(args[0]);
if (target.interf() == null)
usage();
// addition arguments are source addresses to include or exclude
List<InetAddress> includeList = new ArrayList<InetAddress>();
List<InetAddress> excludeList = new ArrayList<InetAddress>();
int argc = 1;
while (argc < args.length) {
String option = args[argc++];
if (argc >= args.length)
usage();
String value = args[argc++];
if (option.equals("-only")) {
parseAddessList(value, includeList);
continue;
}
if (option.equals("-block")) {
parseAddessList(value, excludeList);
continue;
}
usage();
}
if (!includeList.isEmpty() && !excludeList.isEmpty()) {
usage();
}
// create and bind socket
ProtocolFamily family = StandardProtocolFamily.INET;
if (target.group() instanceof Inet6Address) {
family = StandardProtocolFamily.INET6;
}
DatagramChannel dc = DatagramChannel.open(family)
.setOption(StandardSocketOptions.SO_REUSEADDR, true)
.bind(new InetSocketAddress(target.port()));
if (includeList.isEmpty()) {
// join group and block addresses on the exclude list
MembershipKey key = dc.join(target.group(), target.interf());
for (InetAddress source: excludeList) {
key.block(source);
}
} else {
// join with source-specific membership for each source
for (InetAddress source: includeList) {
dc.join(target.group(), target.interf(), source);
}
}
// register socket with Selector
Selector sel = Selector.open();
dc.configureBlocking(false);
dc.register(sel, SelectionKey.OP_READ);
// print out each datagram that we receive
ByteBuffer buf = ByteBuffer.allocateDirect(4096);
for (;;) {
int updated = sel.select();
if (updated > 0) {
Iterator<SelectionKey> iter = sel.selectedKeys().iterator();
while (iter.hasNext()) {
SelectionKey sk = iter.next();
iter.remove();
DatagramChannel ch = (DatagramChannel)sk.channel();
SocketAddress sa = ch.receive(buf);
if (sa != null) {
buf.flip();
printDatagram(sa, buf);
buf.rewind();
buf.limit(buf.capacity());
}
}
}
}
}
}
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