// Suicidal Snail
import java.util.Random;
import org.zeromq.ZContext;
import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Socket;
import org.zeromq.ZThread;
import org.zeromq.ZThread.IAttachedRunnable;
/**
* Suicidal Snail
*
* @author Mariusz Ryndzionek <mryndzionek@gmail.com>
*
*/
public class suisnail
{
private static final long MAX_ALLOWED_DELAY = 1000; // msecs
private static Random rand = new Random(System.currentTimeMillis());
// This is our subscriber. It connects to the publisher and subscribes
// to everything. It sleeps for a short time between messages to
// simulate doing too much work. If a message is more than one second
// late, it croaks.
private static class Subscriber implements IAttachedRunnable
{
@Override
public void run(Object[] args, ZContext ctx, Socket pipe)
{
// Subscribe to everything
Socket subscriber = ctx.createSocket(ZMQ.SUB);
subscriber.subscribe("".getBytes());
subscriber.connect("tcp://localhost:5556");
// Get and process messages
while (true) {
String string = subscriber.recvStr();
System.out.printf("%s\n", string);
long clock = Long.parseLong(string);
// Suicide snail logic
if (System.currentTimeMillis() - clock > MAX_ALLOWED_DELAY) {
System.err.println("E: subscriber cannot keep up, aborting");
break;
}
// Work for 1 msec plus some random additional time
try {
Thread.sleep(1000 + rand.nextInt(2000));
} catch (InterruptedException e) {
break;
}
}
pipe.send("gone and died");
}
}
// .split publisher task
// This is our publisher task. It publishes a time-stamped message to its
// PUB socket every millisecond:
private static class Publisher implements IAttachedRunnable
{
@Override
public void run(Object[] args, ZContext ctx, Socket pipe)
{
// Prepare publisher
Socket publisher = ctx.createSocket(ZMQ.PUB);
publisher.bind("tcp://*:5556");
while (true) {
// Send current clock (msecs) to subscribers
String string = String.format("%d", System.currentTimeMillis());
publisher.send(string);
String signal = pipe.recvStr(ZMQ.DONTWAIT);
if (signal != null) {
break;
}
try {
Thread.sleep(1);
} catch (InterruptedException e) {
}
}
}
}
// .split main task
// The main task simply starts a client and a server, and then
// waits for the client to signal that it has died:
public static void main (String[] args) throws Exception
{
ZContext ctx = new ZContext();
Socket pubpipe = ZThread.fork(ctx, new Publisher());
Socket subpipe = ZThread.fork(ctx, new Subscriber());
subpipe.recvStr();
pubpipe.send("break");
Thread.sleep(100);
ctx.destroy();
}
}