import java.net.DatagramSocket;
import java.net.DatagramPacket;
import java.util.Date;
import java.util.Random;
import java.io.IOException;

public class TimeReceiverDG {
    public static void main (String[] args) {
	Random r = new Random();
	try {
	    DatagramSocket sock = new DatagramSocket (port);

	    DatagramPacket t_packet = new DatagramPacket (new byte[cargo_size], cargo_size);
	    while (true) {
		sock.receive (t_packet);  // blocks
		System.out.println ("Server time: " + 
				    new String (t_packet.getData()) +
				    " from " + t_packet.getAddress().toString() +
				    ":" + t_packet.getPort());
		Thread.sleep (Math.abs(r.nextInt()) % 12 * 1000);
	    }
	}
	catch (IOException e) { System.err.println (e); }
	catch (InterruptedException e) { System.err.println (e); }
    }

    private static final int port = 10001;
    private static final int cargo_size = 10;
}