Synchronized publisher in Java

import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Context;
import org.zeromq.ZMQ.Socket;

/**

  • Synchronized publisher.

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

protected static int SUBSCRIBERS_EXPECTED = 10;

public static void main (String[] args) {
Context context = ZMQ.context(1);

// Socket to talk to clients
Socket publisher = context.socket(ZMQ.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.socket(ZMQ.REP);
syncservice.bind("tcp://*:5562");

System.out.println("Waiting 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);

// clean up
publisher.close();
syncservice.close();
context.term();
}
}