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

public class UdpDaytime {

   public static void main(String[] args) {
      String         host;
      InetAddress    hostAddress;
      byte[]         outBuffer = new byte[1];
      byte[]         inBuffer = new byte[512];
      DatagramPacket request;
      DatagramPacket reply;
      DatagramSocket timeSocket;

      // If number of args < 1, print usage.

      if (args.length < 1) {
         System.out.println("Usage: Daytime <host>");
      } else {
         try {
            // Get the host.

            host = args[0];
            hostAddress = InetAddress.getByName(host);

            System.out.println("Getting daytime from " + hostAddress.toString() + " ...");

            // Create the datagram socket.

            timeSocket = new DatagramSocket();

            // Build the request and the reply buffer.

            request = new DatagramPacket(outBuffer, outBuffer.length, hostAddress, 13);
            reply = new DatagramPacket(inBuffer, inBuffer.length);

            // Send the requests and read the replies.

            try {
               // Set the socket timeout to 5 seconds.

               timeSocket.setSoTimeout(5 * 1000);

               // Send the request and get the reply.

               timeSocket.send(request);
               timeSocket.receive(reply);

               System.out.print("Reply received: " +
                  new String(inBuffer, 0, reply.getLength()));
            } finally {
               timeSocket.close();
            }
         } catch(Exception ex) {
            System.out.println(ex);
         }
      }

      System.exit(0);
   }
}