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import java.net.*;

public final class MultiCastSender
    implements Runnable
{
    private static volatile long messageCounter = 0L;
    private static long lastMessageCounter = 0L;
    private static long lastTimestamp = System.currentTimeMillis();

    public static void main(final String[] args)
        throws Exception
    {
        init(args);

        final byte[] buffer = "This is a string with sufficient data to test a packet sending".getBytes("ASCII");

        final int multiCastPort = 4447;
        final String address = args[0];
        final NetworkInterface networkInterface = NetworkInterface.getByName(args[1]);
        final int count = Integer.parseInt(args[2]);

        final InetAddress interfaceAddress = networkInterface.getInterfaceAddresses().get(0).getAddress();
        final MulticastSocket sendSocket = new MulticastSocket(new InetSocketAddress(interfaceAddress, multiCastPort));
        final InetAddress group = InetAddress.getByName(address);
        final DatagramPacket packet = new DatagramPacket(buffer, buffer.length, group, multiCastPort);

        final Thread t = new Thread(new MultiCastSender());
        t.start();

        while (messageCounter++ < count)
        {
            packet.setData(buffer);
            sendSocket.send(packet);
        }

        sendSocket.close();
        t.interrupt();
        t.join();
    }

    private static void init(final String[] args)
    {
        System.setProperty("java.net.preferIPv4Stack", "true");

        if (3 != args.length)
        {
            System.out.println("Usage: java MultiCastSender <multicast address> <interface name> <# messages>");
            System.exit(1);
        }
    }

    public void run()
    {
        while (!Thread.currentThread().isInterrupted())
        {
            try
            {
                Thread.sleep(1000L);
            }
            catch (InterruptedException ex)
            {
                break;
            }

            final long newTimestamp = System.currentTimeMillis();
            final long duration = newTimestamp - lastTimestamp;
            final long newMessageCounter = messageCounter;
            final long numberOfMessages = newMessageCounter - lastMessageCounter;

            System.out.format("Sent %d messages in %dms\n",
                              Long.valueOf(numberOfMessages),
                              Long.valueOf(duration));

            lastTimestamp = newTimestamp;
            lastMessageCounter = newMessageCounter;
        }
    }
}