net.sf.jinsim.UDPChannel.java Source code

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Here is the source code for net.sf.jinsim.UDPChannel.java

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/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the JInSim Library.
 *
 * The Initial Developer of the Original Code is Rob Heiser.
 *
 * Portions created by the Initial Developer are Copyright (C) 2006
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 *   Rob Heiser <jinsim@kerf.org>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

package net.sf.jinsim;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.MulticastSocket;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Thread that waits for responses from the LFS server, and routes them to any objects that are listening for them.
 * 
 * @author Rob Heiser (jinsim@kerf.org)
 * @since 0.001
 * @see net.sf.jinsim.UDPClient
 * @see net.sf.jinsim.InSimResponse
 * 
 */
public class UDPChannel extends AbstractChannel {

    private ByteBuffer cacheBuffer = ByteBuffer.allocate(1024);

    static Log log = LogFactory.getLog(UDPChannel.class);

    protected DatagramChannel datagramChannel;
    private MulticastSocket multicastSocket;

    protected InetSocketAddress address;

    public UDPChannel(String host, int port, boolean multicast) throws IOException {
        this(new InetSocketAddress(host, port), multicast);
    }

    public UDPChannel(String host, int port) throws IOException {
        this(host, port, false);
    }

    /**
     * Construct a Receiver that is ready to communicate with a LFS server at a particular address.
     * 
     * @param channel
     *            The DatagramChannel that the communication will take place on.
     * @param address
     *            A network address to send acknowledgement (ACK) packets to.
     * @param multicast
     *            Receiver will relay the packets received to a multicast address if multicast is true.
     * @throws IOException
     */
    public UDPChannel(InetSocketAddress address, boolean multicast) throws IOException {
        super();

        datagramChannel = DatagramChannel.open();
        datagramChannel.configureBlocking(false);
        datagramChannel.socket().bind(null);
        //datagramChannel.connect(address);
        this.address = address;

        if (multicast) {
            InetAddress group = InetAddress.getByName("223.223.223.223");
            multicastSocket = new MulticastSocket();
            multicastSocket.joinGroup(group);
        }

    }

    public int getPort() {
        return datagramChannel.socket().getLocalPort();
    }

    @Override
    protected synchronized int receive(ByteBuffer buffer) throws IOException {

        if (cacheBuffer.position() > 0 && cacheBuffer.hasRemaining()) {
            buffer.put(cacheBuffer);
            return buffer.position();
        } else {
            byte[] data = new byte[buffer.limit()];
            cacheBuffer.clear();
            SocketAddress address = datagramChannel.receive(cacheBuffer);
            int size = cacheBuffer.position();
            if (address != null) {
                cacheBuffer.flip();
                int remaining = cacheBuffer.remaining();
                if (remaining > data.length) {
                    remaining = data.length;
                }
                cacheBuffer.get(data, 0, remaining);
                buffer.put(data, 0, remaining);
                return data.length;
            }
            return size;
        }
        /*
        SocketAddress address = datagramChannel.receive(buffer);
        if (address != null) {
           System.out.println("has data: " + buffer.position());
           return buffer.position();
        }
        return 0;
        */
        /*
        DatagramSocket socket = datagramChannel.socket();
            
        receive(DatagramPacket p) 
        */
    }

    @Override
    public synchronized void close() throws IOException {
        super.close();
        datagramChannel.close();
    }

    @Override
    protected synchronized void send(ByteBuffer sendBuffer) throws IOException {
        datagramChannel.send(sendBuffer, address);
    }

}