// network/ChatterServer.java

// (c)2016 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://mindviewinc.com/Books/OnJava/ for more book information.

// {ValidateByHand}

// A server that echoes datagrams

import java.net.*;

import java.io.*;

import onjava.*;

public class ChatterServer {

static final int INPORT = 1711;

private byte[] buf = new byte[1000];

private DatagramPacket dp =

new DatagramPacket(buf, buf.length);

// Can listen & send on the same socket:

private DatagramSocket socket;

public ChatterServer() {

try {

socket = new DatagramSocket(INPORT);

System.out.println("Server started");

while(true) {

// Block until a datagram appears:

socket.receive(dp);

String rcvd = Dgram.toString(dp) +

", from address: " + dp.getAddress() +

", port: " + dp.getPort();

System.out.println(rcvd);

String echoString =

"Echoed: " + rcvd;

// Extract the address and port from the

// received datagram to find out where to

// send it back to:

DatagramPacket echo =

Dgram.toDatagram(echoString,

dp.getAddress(), dp.getPort());

socket.send(echo);

}

} catch(SocketException e) {

System.err.println("Can't open socket");

System.exit(1);

} catch(IOException e) {

System.out.println("Communication error");

throw new RuntimeException(e);

}

}

public static void main(String[] args) {

new TimedAbort(5); // Terminate after 5 seconds

new ChatterServer();

}

}