/** 
 * This program is an example from the book "Internet 
 * programming with Java" by Svetlin Nakov. It is freeware. 
 * For more information: http://www.nakov.com/books/inetjava/ 
 */ 
import java.net.*; 
 
public class UDPDateClient { 
    public static final String DATE_SERVER = "localhost"; 
    public static final int DATE_PORT = 12345; 
    public static final String DATE_REQUEST = "GET DATE"; 
    public static final int TIMEOUT_IN_SECONDS = 5; 
 
    public static void main(String[] args) throws Exception { 
        // Send request to the UDP Date Server 
        DatagramSocket datagramSocket = new DatagramSocket(); 
        String request = DATE_REQUEST; 
        byte[] requestBuf = request.getBytes(); 
        DatagramPacket packetOut = new DatagramPacket( 
            requestBuf, requestBuf.length, 
            InetAddress.getByName(DATE_SERVER), DATE_PORT); 
        datagramSocket.send(packetOut); 
        System.out.println("Sent date request to the server."); 
 
        // Receive the server response 
        byte[] responseBuf = new byte[256]; 
        DatagramPacket packetIn = 
            new DatagramPacket(responseBuf, responseBuf.length); 
        datagramSocket.setSoTimeout(TIMEOUT_IN_SECONDS * 1000); 
        try { 
            datagramSocket.receive(packetIn); 
            String response = new String( 
                responseBuf, 0, packetIn.getLength()); 
            System.out.println("Server response: " + response); 
        } catch (SocketTimeoutException ste) { 
            System.err.println("Timeout! No response received" + 
                " in " + TIMEOUT_IN_SECONDS + " seconds."); 
        } 
        datagramSocket.close(); 
    } 
}