Example usage for java.net MulticastSocket setTimeToLive

Introduction

In this page you can find the example usage for java.net MulticastSocket setTimeToLive.

Prototype

public void setTimeToLive(int ttl) throws IOException 

Source Link

Document

Set the default time-to-live for multicast packets sent out on this MulticastSocket in order to control the scope of the multicasts.

Usage

From source file:org.openhab.binding.wemo.internal.WemoBinding.java

public void wemoDiscovery() {
    logger.debug("wemoDiscovery() is called!");
    try {//from   w ww .j a v  a 2s  .  co m
        final int SSDP_PORT = 1900;
        final int SSDP_SEARCH_PORT = 1901;

        // Broadcast address
        final String SSDP_IP = "239.255.255.250";

        // Connection timeout
        int TIMEOUT = 1000;

        // Send from localhost:1901
        InetAddress localhost = InetAddress.getLocalHost();
        InetSocketAddress srcAddress = new InetSocketAddress(localhost, SSDP_SEARCH_PORT);

        // Send to 239.255.255.250:1900
        InetSocketAddress dstAddress = new InetSocketAddress(InetAddress.getByName(SSDP_IP), SSDP_PORT);

        // Request-Packet-Constructor
        StringBuffer discoveryMessage = new StringBuffer();
        discoveryMessage.append("M-SEARCH * HTTP/1.1\r\n");
        discoveryMessage.append("HOST: " + SSDP_IP + ":" + SSDP_PORT + "\r\n");
        discoveryMessage.append("MAN: \"ssdp:discover\"\r\n");
        discoveryMessage.append("MX: 5\r\n");
        discoveryMessage.append("ST: urn:Belkin:service:basicevent:1\r\n");
        discoveryMessage.append("\r\n");
        logger.trace("Request: {}", discoveryMessage.toString());
        byte[] discoveryMessageBytes = discoveryMessage.toString().getBytes();
        DatagramPacket discoveryPacket = new DatagramPacket(discoveryMessageBytes, discoveryMessageBytes.length,
                dstAddress);

        // Send multi-cast packet
        MulticastSocket multicast = null;
        try {
            multicast = new MulticastSocket(null);
            multicast.bind(srcAddress);
            logger.trace("Source-Address = '{}'", srcAddress);
            multicast.setTimeToLive(5);
            logger.trace("Send multicast request.");
            multicast.send(discoveryPacket);
        } finally {
            logger.trace("Multicast ends. Close connection.");
            multicast.disconnect();
            multicast.close();
        }

        // Response-Listener
        MulticastSocket wemoReceiveSocket = null;
        DatagramPacket receivePacket = null;
        try {
            wemoReceiveSocket = new MulticastSocket(SSDP_SEARCH_PORT);
            wemoReceiveSocket.setTimeToLive(10);
            wemoReceiveSocket.setSoTimeout(TIMEOUT);
            logger.debug("Send datagram packet.");
            wemoReceiveSocket.send(discoveryPacket);

            while (true) {
                try {
                    logger.debug("Receive SSDP Message.");
                    receivePacket = new DatagramPacket(new byte[2048], 2048);
                    wemoReceiveSocket.receive(receivePacket);
                    final String message = new String(receivePacket.getData());
                    if (message.contains("Belkin")) {
                        logger.trace("Received message: {}", message);
                    }

                    new Thread(new Runnable() {
                        @Override
                        public void run() {
                            if (message != null) {
                                String location = StringUtils.substringBetween(message, "LOCATION: ",
                                        "/setup.xml");
                                String udn = StringUtils.substringBetween(message, "USN: uuid:",
                                        "::urn:Belkin");
                                if (udn != null) {
                                    logger.trace("Save location '{}' for WeMo device with UDN '{}'", location,
                                            udn);
                                    wemoConfigMap.put(udn, location);
                                    logger.info("Wemo Device with UDN '{}' discovered", udn);
                                }
                            }
                        }
                    }).start();

                } catch (SocketTimeoutException e) {
                    logger.debug("Message receive timed out.");
                    for (String name : wemoConfigMap.keySet()) {
                        logger.trace(name + ":" + wemoConfigMap.get(name));
                    }
                    break;
                }
            }
        } finally {
            if (wemoReceiveSocket != null) {
                wemoReceiveSocket.disconnect();
                wemoReceiveSocket.close();
            }
        }

    } catch (Exception e) {
        logger.error("Could not start wemo device discovery", e);
    }

}

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