Java Code Examples for java.nio.channels.DatagramChannel#write()

public void run() {
    try {
        DatagramChannel dc = DatagramChannel.open();
        ByteBuffer bb = ByteBuffer.allocateDirect(12);
        bb.order(ByteOrder.BIG_ENDIAN);
        bb.putInt(1).putLong(1);
        bb.flip();
        InetAddress address = InetAddress.getLocalHost();
        InetSocketAddress isa = new InetSocketAddress(address, port);
        dc.connect(isa);
        clientISA = dc.getLocalAddress();
        dc.write(bb);
    } catch (Exception ex) {
        e = ex;
    }
}
 

@Test
public void test() throws Exception {
    DatagramChannel channel = DatagramChannel.open();
    channel.configureBlocking(true);
    channel.connect(new InetSocketAddress(HOSTNAME, PORT_CRUSHER));

    try {
        ByteBuffer bb = ByteBuffer.allocate(1024);
        bb.limit(800);
        bb.position(0);

        channel.write(bb);

        Thread.sleep(1001);
    } finally {
        NioUtils.close(channel);
    }
}
 

@Test
public void test() throws Exception {
    DatagramChannel channel = DatagramChannel.open();
    channel.configureBlocking(true);
    channel.connect(new InetSocketAddress(HOSTNAME_BIND, PORT_CRUSHER));

    try {
        ByteBuffer bb = ByteBuffer.allocate(1024);
        bb.limit(800);
        bb.position(0);

        channel.write(bb);

        Thread.sleep(1002);
    } finally {
        NioUtils.close(channel);
    }
}
 

private static void test() throws Exception {
    DatagramChannel dc = DatagramChannel.open();
    InetAddress localHost = InetAddress.getLocalHost();
    dc.bind(new InetSocketAddress(localHost, 0));

    Server server = new Server(dc.getLocalAddress());
    Thread serverThread = new Thread(server);
    serverThread.start();

    try {
        InetSocketAddress isa = new InetSocketAddress(localHost, server.port());
        dc.connect(isa);

        ByteBuffer bb = ByteBuffer.allocateDirect(12);
        bb.order(ByteOrder.BIG_ENDIAN);
        bb.putInt(1).putLong(1);
        bb.flip();

        dc.write(bb);
        bb.rewind();
        dc.write(bb);
        bb.rewind();
        dc.write(bb);

        Thread.sleep(2000);

        serverThread.interrupt();
        server.throwException();
    } finally {
        dc.close();
    }
}
 

private void handshake(DatagramChannel tunnel) throws Exception {
    // To build a secured tunnel, we should perform mutual authentication
    // and exchange session keys for encryption. To keep things simple in
    // this demo, we just send the shared secret in plaintext and wait
    // for the server to send the parameters.

    // Allocate the buffer for handshaking.
    ByteBuffer packet = ByteBuffer.allocate(1024);

    // Control messages always start with zero.
    packet.put((byte) 0).put(mSharedSecret).flip();

    // Send the secret several times in case of packet loss.
    for (int i = 0; i < 3; ++i) {
        packet.position(0);
        tunnel.write(packet);
    }
    packet.clear();

    // Wait for the parameters within a limited time.
    for (int i = 0; i < 50; ++i) {
        Thread.sleep(100);

        // Normally we should not receive random packets.
        int length = tunnel.read(packet);
        if (length > 0 && packet.get(0) == 0) {
            configure(new String(packet.array(), 1, length - 1).trim());
            return;
        }
    }
    throw new IllegalStateException("Timed out");
}
 

private int __doChannelWrite(DatagramChannel channel, ByteBuffer buffer) throws IOException {
    if (channel != null) {
        return channel.write(buffer);
    }
    buffer.reset();
    return 0;
}
 

private void handshake(DatagramChannel tunnel) throws Exception {
    // To build a secured tunnel, we should perform mutual authentication
    // and exchange session keys for encryption. To keep things simple in
    // this demo, we just send the shared secret in plaintext and wait
    // for the server to send the parameters.
    // Allocate the buffer for handshaking.
    ByteBuffer packet = ByteBuffer.allocate(1024);
    if (false){
        // Control messages always start with zero.
        packet.put((byte) 0).put(mSharedSecret).flip();
        // Send the secret several times in case of packet loss.
        for (int i = 0; i < 3; ++i) {
            packet.position(0);
            tunnel.write(packet);
        }
        packet.clear();
    }

    // Wait for the parameters within a limited time.
    for (int i = 0; i < 50; ++i) {
        Thread.sleep(100);
        // Normally we should not receive random packets.
        int length = tunnel.read(packet);
        if (length > 0 && packet.get(0) == 0) {
            configure(new String(packet.array(), 1, length - 1).trim());
            return;
        }
    }
    throw new IllegalStateException("Timed out");
}
 

private static void measureRoundTrip(
    final Histogram histogram,
    final ByteBuffer buffer,
    final DatagramChannel[] receiveChannels,
    final DatagramChannel writeChannel,
    final AtomicBoolean running)
    throws IOException
{
    for (int sequenceNumber = 0; sequenceNumber < Common.NUM_MESSAGES; sequenceNumber++)
    {
        final long timestampNs = System.nanoTime();

        buffer.clear();
        buffer.putLong(sequenceNumber);
        buffer.putLong(timestampNs);
        buffer.flip();

        writeChannel.write(buffer);

        buffer.clear();
        boolean available = false;
        while (!available)
        {
            if (!running.get())
            {
                return;
            }

            for (int i = receiveChannels.length - 1; i >= 0; i--)
            {
                if (null != receiveChannels[i].receive(buffer))
                {
                    available = true;
                    break;
                }
            }
        }

        final long receivedSequenceNumber = buffer.getLong(0);
        if (receivedSequenceNumber != sequenceNumber)
        {
            throw new IllegalStateException("Data Loss:" + sequenceNumber + " to " + receivedSequenceNumber);
        }

        final long durationNs = System.nanoTime() - buffer.getLong(SIZE_OF_LONG);
        histogram.recordValue(durationNs);
    }

    histogram.outputPercentileDistribution(System.out, 1000.0);
}
 

public static void main(final String[] args) throws IOException
{
    int numChannels = 1;
    if (1 == args.length)
    {
        numChannels = Integer.parseInt(args[0]);
    }

    final ByteBuffer buffer = ByteBuffer.allocateDirect(MTU_LENGTH_DEFAULT);

    final DatagramChannel[] receiveChannels = new DatagramChannel[numChannels];
    for (int i = 0; i < receiveChannels.length; i++)
    {
        receiveChannels[i] = DatagramChannel.open();
        Common.init(receiveChannels[i]);
        receiveChannels[i].bind(new InetSocketAddress("localhost", Common.PING_PORT + i));
    }

    final InetSocketAddress writeAddress = new InetSocketAddress("localhost", Common.PONG_PORT);
    final DatagramChannel writeChannel = DatagramChannel.open();
    Common.init(writeChannel, writeAddress);

    final AtomicBoolean running = new AtomicBoolean(true);
    SigInt.register(() -> running.set(false));

    while (true)
    {
        buffer.clear();

        boolean available = false;
        while (!available)
        {
            if (!running.get())
            {
                return;
            }

            for (int i = receiveChannels.length - 1; i >= 0; i--)
            {
                if (null != receiveChannels[i].receive(buffer))
                {
                    available = true;
                    break;
                }
            }
        }

        final long receivedSequenceNumber = buffer.getLong(0);
        final long receivedTimestamp = buffer.getLong(SIZE_OF_LONG);

        buffer.clear();
        buffer.putLong(receivedSequenceNumber);
        buffer.putLong(receivedTimestamp);
        buffer.flip();

        writeChannel.write(buffer);
    }
}