org.squidy.manager.protocol.multicast.MulticastServer.java Source code

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Here is the source code for org.squidy.manager.protocol.multicast.MulticastServer.java

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/**
 * Squidy Interaction Library is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 * 
 * Squidy Interaction Library is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with Squidy Interaction Library. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * 2009 Human-Computer Interaction Group, University of Konstanz.
 * <http://hci.uni-konstanz.de>
 * 
 * Please contact info@squidy-lib.de or visit our website
 * <http://www.squidy-lib.de> for further information.
 */

package org.squidy.manager.protocol.multicast;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.squidy.manager.protocol.udp.UDPListener;
import org.squidy.manager.protocol.udp.UDPServer;

/**
 * <code>MuliticastServer</code>.
 *
 * <pre>
 * Date: Oct 17, 2008
 * Time: 7:56:58 PM
 * </pre>
 * 
 * @author Roman R&auml;dle, <a
 *         href="mailto:Roman.Raedle@uni-konstanz.de">Roman.Raedle@uni-konstanz.de</a>,
 *         University of Konstanz
 * @version $Id: MulticastServer.java 772 2011-09-16 15:39:44Z raedle $
 * @since 1.1.0
 */
// TODO [RR]: Use UDPServer as superclass.
public class MulticastServer extends Thread {

    // Logger to log info, error, debug,... messages.
    private static final Log LOG = LogFactory.getLog(UDPServer.class);

    private MulticastSocket socket;

    private InetAddress group;

    private static final int BUFFER_SIZE = 1024;

    private String data = "";

    protected List<MulticastListener> listeners = Collections.synchronizedList(new ArrayList<MulticastListener>());

    private boolean running = true;

    public MulticastServer(InetAddress group, int port) {
        try {
            this.group = group;

            socket = new MulticastSocket(port);
            socket.joinGroup(group);
            start();
            LOG.info("Multicast server started on port " + port);
        } catch (IOException e) {
            LOG.error("Couldn't start multicast server on port " + port);
        }

    }

    public void addMulticastListener(MulticastListener listener) {
        listeners.add(listener);
    }

    public void removeMulticastListener(MulticastListener listener) {
        listeners.remove(listener);
    }

    public void close() {
        running = false;
        listeners.clear();

        try {
            socket.leaveGroup(group);
        } catch (IOException e) {
            if (LOG.isErrorEnabled()) {
                LOG.error(e.getMessage(), e);
            }
        }

        socket.close();
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Thread#run()
     */
    @Override
    public void run() {
        while (running) {
            try {
                byte[] buffer = new byte[BUFFER_SIZE];
                DatagramPacket packet = new DatagramPacket(buffer, BUFFER_SIZE);
                socket.receive(packet);
                data = new String(packet.getData());
                int last = 0;
                while (last < BUFFER_SIZE) {
                    if (buffer[last] == 0)
                        break;
                    last++;
                }
                data = data.substring(0, last);
                if (last == BUFFER_SIZE) {
                    LOG.error("Input buffer overflow");
                } else {
                    for (MulticastListener listener : listeners) {
                        listener.parseData(data);
                    }
                }

                for (MulticastListener listener : listeners) {
                    listener.parseData(packet.getData());
                }
            } catch (IOException e) {
                if (LOG.isErrorEnabled()) {
                    LOG.error("Connection error occured.");
                }
            }
        }
        socket.close();
    }
}