--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/sample/nio/multicast/Reader.java	Sun Aug 31 18:39:01 2008 +0100
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2007-2008 Sun Microsystems, Inc.  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 Sun Microsystems 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.
+ */
+
+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(StandardSocketOption.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());
+                    }
+                }
+            }
+        }
+    }
+}