/*
  UDPEchoClient.java
  A simple echo client with no error handling
*/

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketAddress;

public class UDPEchoClient {
    public static final int BUFSIZE= 1024;
    public static final int MYPORT= 0;
    public static final String MSG= "An Echo Message!";

    public static void main(String[] args) throws IOException {
    byte[] buf= new byte[BUFSIZE];
    if (args.length != 2) {
        System.err.printf("usage: %s server_name port\n", args[1]);
        System.exit(1);
    }

    /* Create socket */
    DatagramSocket socket= new DatagramSocket(null);

    /* Create local endpoint using bind() */
    SocketAddress localBindPoint= new InetSocketAddress(MYPORT);
    socket.bind(localBindPoint);

    /* Create remote endpoint */
    SocketAddress remoteBindPoint=
        new InetSocketAddress(args[0],
                  Integer.valueOf(args[1]));

    /* Create datagram packet for sending message */
    DatagramPacket sendPacket=
        new DatagramPacket(MSG.getBytes(),
                   MSG.length(),
                   remoteBindPoint);

    /* Create datagram packet for receiving echoed message */
    DatagramPacket receivePacket= new DatagramPacket(buf, buf.length);

    /* Send and receive message*/
    socket.send(sendPacket);
    socket.receive(receivePacket);

    /* Compare sent and received message */
    String receivedString=
        new String(receivePacket.getData(),
               receivePacket.getOffset(),
               receivePacket.getLength());
    if (receivedString.compareTo(MSG) == 0)
        System.out.printf("%d bytes sent and received\n", receivePacket.getLength());
    else
        System.out.printf("Sent and received msg not equal!\n");
    socket.close();
    }
}