Synchronized subscriber in Java

package guide;

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

/**

  • Synchronized subscriber.

*/
public class syncsub
{

public static void main(String[] args)
{
try (ZContext context = new ZContext()) {
// First, connect our subscriber socket
Socket subscriber = context.createSocket(SocketType.SUB);
subscriber.connect("tcp://localhost:5561");
subscriber.subscribe(ZMQ.SUBSCRIPTION_ALL);

// Second, synchronize with publisher
Socket syncclient = context.createSocket(SocketType.REQ);
syncclient.connect("tcp://localhost:5562");

// - send a synchronization request
syncclient.send(ZMQ.MESSAGE_SEPARATOR, 0);

// - wait for synchronization reply
syncclient.recv(0);

// Third, get our updates and report how many we got
int update_nbr = 0;
while (true) {
String string = subscriber.recvStr(0);
if (string.equals("END")) {
break;
}
update_nbr++;
}
System.out.println("Received " + update_nbr + " updates.");
}
}
}