/******************************************************************************/
/*                                                                            */
/*                                                  FILE: DatagramServer.java */
/*                                                                            */
/*  Demonstrates a simple datagram server                                     */
/*  =====================================                                     */
/*                                                                            */
/*  V1.01   16-DEC-1998 Te                                                    */
/*  V1.10   12-OCT-2009 Te Cleaned up and extended                            */
/*                                                                            */
/******************************************************************************/

import java.net.* ;
import java.awt.* ;
import java.applet.* ;

/**
 *  A simple datagram server
 *  Shows how to send and receive UDP packets in Java
 *
 *  @author  P. Tellenbach, http://www.heimetli.ch
 *  @version V1.01
 */
public class DatagramServer
{
   private final static int PACKETSIZE = 100 ;

   public static void main( String args[] )
   {
      // Check the arguments
      if( args.length != 1 )
      {
         System.out.println( "usage: DatagramServer port" ) ;
         return ;
      }

      try
      {
         // Convert the argument to ensure that is it valid
         int port = Integer.parseInt( args[0] ) ;

         // Construct the socket
         DatagramSocket socket = new DatagramSocket( port ) ;

         System.out.println( "The server is ready..." ) ;


         for( ;; )
         {
            // Create a packet
            DatagramPacket packet = new DatagramPacket( new byte[PACKETSIZE], PACKETSIZE ) ;

            // Receive a packet (blocking)
            socket.receive( packet ) ;

            // Print the packet
            System.out.println( packet.getAddress() + " " + packet.getPort() + ": " + new String(packet.getData()) ) ;

            // Return the packet to the sender
            socket.send( packet ) ;
        }  
     }
     catch( Exception e )
     {
        System.out.println( e ) ;
     }
  }
}