void timerExpired() {
// should not happen, but if it does,
// fabricate a permanent error and forward up
DatagramRejectedMessage msg =
new DatagramRejectedMessage(message.getDestNodeID(), message.getSourceNodeID(), 0x0100);
System.out.println(
"Never received reply for datagram "
+ (message != null ? message.toString() : " == null"));
handleDatagramRejected(msg, null);
}
/** Handle "Datagram Acknowledged" message */
@Override
public void handleDatagramAcknowledged(DatagramAcknowledgedMessage msg, Connection sender) {
// check if this is from right source & to us
if (!(msg.getDestNodeID() != null
&& msg.getSourceNodeID() != null
&& msg.getDestNodeID().equals(message.getSourceNodeID())
&& message.getDestNodeID().equals(msg.getSourceNodeID()))) {
// not for us, just forward
toUpstream.put(msg, toUpstream);
return;
}
endTimeout();
// forward message upstream
toUpstream.put(msg, toUpstream);
// and allow sending another
new Thread(new Consumer(queue)).start();
}
/** Handle "Datagram Rejected" message */
@Override
public void handleDatagramRejected(DatagramRejectedMessage msg, Connection sender) {
// check if this is from right source & to us
if (!(msg.getDestNodeID() != null
&& msg.getSourceNodeID() != null
&& msg.getDestNodeID().equals(message.getSourceNodeID())
&& message.getDestNodeID().equals(msg.getSourceNodeID()))) {
// not for us, just forward
toUpstream.put(msg, toUpstream);
return;
}
endTimeout();
// check if resend permitted
if (msg.canResend()) {
forwardDownstream();
} else {
// forward upstream to originator and let them sort it out
toUpstream.put(msg, toUpstream);
// and allow sending another
new Thread(new Consumer(queue)).start();
}
}
public static void main(String[] args) {
int serverPort = 13; // default port
if (args.length == 1) serverPort = Integer.parseInt(args[0]);
try {
// instantiates a datagram socket for both sending
// and receiving data
MyServerDatagramSocket mySocket = new MyServerDatagramSocket(serverPort);
System.out.println("Daytime server ready.");
while (true) { // forever loop
DatagramMessage request = mySocket.receiveMessageAndSender();
System.out.println("Request received");
// The message received is unimportant; it is the sender's
// address that we need in order to reply.
// Now obtain the timestamp from the local system.
Date timestamp = new Date();
System.out.println("timestamp sent: " + timestamp.toString());
// Now send the reply to the requestor
mySocket.sendMessage(request.getAddress(), request.getPort(), timestamp.toString());
} // end while
} // end try
catch (Exception ex) {
System.out.println("There is a problem: " + ex);
} // end catch
} // end main
void endTimeout() {
if (timer != null) timer.cancel();
else
System.out.println(
"Found timer null for datagram " + (message != null ? message.toString() : " == null"));
}