Synchronized publisher in Java

package guide;

import org.zeromq.SocketType;
import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Socket;
import org.zeromq.ZContext;

/**

  • Synchronized publisher.

*/
public class syncpub
{
/**
* We wait for 10 subscribers
*/

protected static int SUBSCRIBERS_EXPECTED = 10;

public static void main(String[] args)
{
try (ZContext context = new ZContext()) {
// Socket to talk to clients
Socket publisher = context.createSocket(SocketType.PUB);
publisher.setLinger(5000);
// In 0MQ 3.x pub socket could drop messages if sub can follow the
// generation of pub messages
publisher.setSndHWM(0);
publisher.bind("tcp://*:5561");

// Socket to receive signals
Socket syncservice = context.createSocket(SocketType.REP);
syncservice.bind("tcp://*:5562");

System.out.println("Waiting for subscribers");
// Get synchronization from subscribers
int subscribers = 0;
while (subscribers < SUBSCRIBERS_EXPECTED) {
// - wait for synchronization request
syncservice.recv(0);

// - send synchronization reply
syncservice.send("", 0);
subscribers++;
}
// Now broadcast exactly 1M updates followed by END
System.out.println("Broadcasting messages");

int update_nbr;
for (update_nbr = 0; update_nbr < 1000000; update_nbr++) {
publisher.send("Rhubarb", 0);
}

publisher.send("END", 0);
}
}
}