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

public class DayTimeUDPServer extends Thread {

   DatagramSocket 	socket;
   static String 	hostName = "yps";
   int			port     = 4242;


   public DayTimeUDPServer()	{
   }

   public DayTimeUDPServer(int port)	{
        try { 
            socket = new DatagramSocket(port);
            System.out.println ("Listening on port: "
                + socket.getLocalPort());
        } catch(Exception e) {
            System.out.println(e);
        }
   }

    private void printMessage()	{
	System.out.println("-h		---->	help");
	System.out.println("[-host 		hostName");
	System.out.println(" -port 		port");
	System.out.println(" {-port 		port}");
	System.out.println("or ");
	System.out.println(" no argument");
   }
	
   /**
     * Parse the commandlind arguments and sets variables.
     */
   public void parseArgs(String args[]) {

	for (int i = 0; i < args.length; i ++) {
	   	if (args[i].equals("-h")) 
			printMessage();
	   	else if (args[i].equals("-host")) 
			hostName = args[++i];
	   	else if (args[i].equals("-port")) {
			port = new Integer(args[++i]).intValue();
			new DayTimeUDPServer(port).start();
		}
	}
   }
   
   public void run()	{
        byte[] buf = new byte[256];
        try {
            for(;;) {
		String sendThis = "es schlaegt: " + new Date();
                DatagramPacket packet = new DatagramPacket(buf, buf.length);
		socket.receive(packet);
                InetAddress address = packet.getAddress();
                int port = packet.getPort();
		buf = sendThis.getBytes();
                packet = new DatagramPacket(buf, buf.length, address, port);
		System.out.println("Sending to port: " + port );
		System.out.println("Sending    data: " + new String(buf) );
                socket.send(packet);
            }
        } catch(Exception e) {
            System.out.println(e);
	    e.printStackTrace();
        }
   }

    public static void main(String argv[]) {
	if ( argv.length == 0 )
		new DayTimeUDPServer(0).start();
	else
		new DayTimeUDPServer().parseArgs(argv);
    }
}