Subversion Repositories programming

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

public class P2_Client
{
    private static int soTimeout = 3000; // 3000 ms timeout = 3 sec
    private static DatagramSocket socket;
    private static DatagramPacket packet;
    private static int portNumber = 1337;

    public static String readPacket (int maxlen)
    {
        byte[] buf = new byte[maxlen];
        packet = new DatagramPacket (buf, buf.length);

        try {
            socket.receive (packet);
        } catch (SocketTimeoutException e) {
            System.out.println ("Read timed out, requesting retransmit");
            return null;
        } catch (PortUnreachableException e) {
            System.out.println ("Caught PortUnreachableException, are you" +
                                " sure the server is running?");
            System.exit(1);
        } catch (IOException e) {
            System.out.println ("Caught exception in readPacket()");
            e.printStackTrace();
            return null;
        }

        return new String (buf, 0, packet.getLength()/*- 1*/);
    }
    public static boolean writePacket (String msg) throws Exception
    {
        InetAddress address = InetAddress.getLocalHost();
        int port = portNumber;

        byte[] buf = msg.getBytes();
        packet = new DatagramPacket (buf, buf.length, address, port);

        try {
            socket.send (packet);
        } catch (PortUnreachableException e) {
            System.out.println ("Caught PortUnreachableException, are " +
                                "you sure the server is running?");
            System.exit(1);
        } catch (IOException e) {
            System.out.println ("Caught exception in writePacket()");
            e.printStackTrace();
            return false;
        }

        return true;
    }

    public static void main (String[] args) throws Exception
    {
        int dropHowMany = 0;
        socket = new DatagramSocket();
        socket.connect (InetAddress.getLocalHost(), portNumber);
        socket.setSoTimeout (soTimeout);

        BufferedReader kbd = new BufferedReader (
                                 new InputStreamReader (
                                     System.in));

        try {
            dropHowMany = Integer.parseInt(args[0]);
        } catch (ArrayIndexOutOfBoundsException e) {
            System.err.println ("You need to call the program with \'java P2_Client <num>\'");
            System.exit(1);
        }

        writePacket ("DROP" + dropHowMany);

        System.out.print ("% decode: ");
        String msg = kbd.readLine();
        String reply;
        boolean done = false;

        while (!done)
        {
            writePacket (msg);
            reply = readPacket(5);

            while (reply == null)
            {
                System.out.println ("Packet lost, retransmitting...");
                writePacket (msg);
                reply = readPacket(5);
            }

            if (reply.equals("QUIT"))
            {
                done = true;
                continue;
            }

            System.out.println ("-> reply: " + reply);
            System.out.print ("% decode: ");
            msg = kbd.readLine();
        }
    }
}