taskvent.java

package guide;

import java.util.Random;

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

//
//  Task ventilator in Java
//  Binds PUSH socket to tcp://localhost:5557
//  Sends batch of tasks to workers via that socket
//
public class taskvent
{
    public static void main(String[] args) throws Exception
    {
        try (ZContext context = new ZContext()) {
            //  Socket to send messages on
            ZMQ.Socket sender = context.createSocket(SocketType.PUSH);
            sender.bind("tcp://*:5557");

            //  Socket to send messages on
            ZMQ.Socket sink = context.createSocket(SocketType.PUSH);
            sink.connect("tcp://localhost:5558");

            System.out.println("Press Enter when the workers are ready: ");
            System.in.read();
            System.out.println("Sending tasks to workers\n");

            //  The first message is "0" and signals start of batch
            sink.send("0", 0);

            //  Initialize random number generator
            Random srandom = new Random(System.currentTimeMillis());

            //  Send 100 tasks
            int task_nbr;
            int total_msec = 0; //  Total expected cost in msecs
            for (task_nbr = 0; task_nbr < 100; task_nbr++) {
                int workload;
                //  Random workload from 1 to 100msecs
                workload = srandom.nextInt(100) + 1;
                total_msec += workload;
                System.out.print(workload + ".");
                String string = String.format("%d", workload);
                sender.send(string, 0);
            }
            System.out.println("Total expected cost: " + total_msec + " msec");
            Thread.sleep(1000); //  Give 0MQ time to deliver
        }
    }
}