server.java

DSr project for the java applications

package dsr;



import java.net.*;
import java.io.*;

//this implements the server that listens for the DSR packets and inserts them into the
//event queue which then handles the packets.
public class Server implements Runnable {
  private DatagramSocket socket;
  private DatagramPacket packet;
  static final int MAXLEN = 1000;

  //the function that creates the socket an listens for the packets to be received
  public static void startServ(int port) throws IOException {
    if (!RouteTable.routingTable.isEmpty()){
      RouteTableEntry tmpRoute =
          new RouteTableEntry((RouteTableEntry)RouteTable.routingTable.lastElement());
      InetAddress tmpAd = tmpRoute.dstIP;

      //create a socket to receive datagrams on specified ports.
      System.out.println("the tmpAd is " + tmpAd.toString());
      DatagramSocket socket = new DatagramSocket(port, tmpAd);

      //DatagramSocket socket = new DatagramSocket(port);
      DatagramPacket packet = new DatagramPacket(new byte[MAXLEN], MAXLEN);

      //for(int threadCT = 0; threadCT < 10; threadCT++) {
      Server agent = new Server(socket, packet);
      Thread thread = new Thread(agent);
      thread.start();
      System.out.println("Created thread = " + thread.getName());
      //}
    }
    else {
      System.out.println("there is no available network interface");
    }
  }

  //constructor
  public Server (DatagramSocket socket, DatagramPacket packet) {
    this.socket = socket;
    this.packet = packet;
  }

  //the run function to handle the threads.
  //it receives the packet it calls handleConnection() to handle that.
  public void run() {
    for (;;) {
      try {
        RouteTable.PrintRouteTable();
        System.out.println("waiting for next packet");
        socket.receive(packet);
        handleConnection(socket, packet);
      } catch (IOException e) {
        System.out.println("Exception in run = " + e.getMessage());
      }
    }
  }

  //the function that inserts the packet received into the event queue
  public void handleConnection(DatagramSocket socket,
                               DatagramPacket packet) throws IOException {
      //the packet that has been received has to be appended to the event queue.
      //InterfaceList.findInterface()
      InetAddress srcIP = packet.getAddress();
      InetAddress dstIP = socket.getLocalAddress();
      System.out.println("the packet was received from" + srcIP.toString());

      if (EventQueue.insertEventQueueEntry(packet, srcIP, dstIP));
  }
}