Connection.java

package iax.protocol.connection;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

import iax.protocol.peer.Peer;

/**
 * Makes the udp connection with the asterisk host for sending and receiving frames
 */
public class Connection implements Runnable {

    // Maximun length of the udp buffer for receiving frames
    private static final int BUFFER_LENGTH = 4096;
    // Port udp of the asterisk host
    private static final int IAX_PORT = 4569;
    // Flag to determine if the thread is running or not
    private boolean running = true;
    // Peer that handle the received frames (and send the sending frames)
    private Peer peer;
    // Inet addres of the asterisk host
    private InetAddress hostIAddr;
    // Socket udp to send and receive frames
    private DatagramSocket socket;

    /**
     * Constructor. Initializes the socket and the inet addres of the asterisk host
     * @param peer peer that handle the received frames (and send the sending frames)
     * @param host ip of the asterisk host
     */
    public Connection(Peer peer, String host) {
        this.peer = peer;
        try {
            hostIAddr = InetAddress.getByName(host);
            socket = new DatagramSocket();
            //socket = new DatagramSocket(IAX_PORT);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Starts the thread for receiving frames
     */
    public void start() {
        Thread t = new Thread(this);
        t.start();
    }

    /**
     * Stops the thread for receiving frames
     */
    public synchronized void stop() {
        this.running = false;
    }

    public void run() {
        while (running) {
            try {
                // Create a packet for receiving the data of a frame
                DatagramPacket packet = new DatagramPacket(new byte[
                        BUFFER_LENGTH], BUFFER_LENGTH);
                // Wait until receiving the data of a packet
                socket.receive(packet);
                recv(packet);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /*
     * Handles the packets received by delegating in the peer
     */
    private void recv(DatagramPacket packet) {
        // Data length received (is less or equal than the total length of the packet used for receiving data)
        int length = packet.getLength();
        byte[] buffer = new byte[length];
        System.arraycopy(packet.getData(), 0, buffer, 0, length);
        peer.handleRecvFrame(buffer);
    }

    /**
     * Sends a packet udp from an array of bytes
     * @param data the data to send
     */
    public void send(byte data[]) {
        try {
            DatagramPacket packet = new DatagramPacket(data, data.length,
                    hostIAddr, IAX_PORT);
            socket.send(packet);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}