/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

import java.util.*;
import java.util.concurrent.*;

/**
 * One FJ publisher, many subscribers
 */
public class SubmissionPublisherLoops2 {
    static final int ITEMS = 1 << 22;
    static final int CONSUMERS  = 64;
    static final int CAP        = Flow.defaultBufferSize();
    static final int REPS = 9;

    static final Phaser phaser = new Phaser(CONSUMERS + 1);
    static final ExecutorService exec = ForkJoinPool.commonPool();
    //    static final ExecutorService exec = Executors.newFixedThreadPool(2);
    //    static final ExecutorService exec = new ForkJoinPool(4);

    static final class Sub implements Flow.Subscriber<Boolean> {
        Flow.Subscription sn;
        int count;
        public void onSubscribe(Flow.Subscription s) {
            (sn = s).request(CAP);
        }
        public void onNext(Boolean t) {
            if ((++count & (CAP - 1)) == (CAP >>> 1))
                sn.request(CAP);
        }
        public void onError(Throwable t) { t.printStackTrace(); }
        public void onComplete() {
            if (count != ITEMS)
                System.out.println("Error: remaining " + (ITEMS - count));
            phaser.arrive();
        }
    }

    static final class Pub extends RecursiveAction implements Runnable {
        final SubmissionPublisher<Boolean> pub =
            new SubmissionPublisher<Boolean>(exec, CAP);
        public void compute() {
            SubmissionPublisher<Boolean> p = pub;
            for (int i = 0; i < CONSUMERS; ++i)
                p.subscribe(new Sub());
            for (int i = 0; i < ITEMS; ++i)
                p.submit(Boolean.TRUE);
            p.close();
        }
        public void run() { compute(); }
    }

    static final long NPS = (1000L * 1000 * 1000);

    public static void main(String[] args) throws Exception {
        int reps = REPS;
        if (args.length > 0)
            reps = Integer.parseInt(args[0]);

        System.out.println("ITEMS: " + ITEMS +
                           " CONSUMERS: " + CONSUMERS +
                           " CAP: " + CAP);
        for (int rep = 0; rep < reps; ++rep) {
            oneRun();
            System.out.println(exec);
            Thread.sleep(1000);
        }
        if (exec != ForkJoinPool.commonPool())
            exec.shutdown();
    }

    static void oneRun() throws Exception {
        long startTime = System.nanoTime();
        exec.execute(new Pub());
        phaser.arriveAndAwaitAdvance();
        long elapsed = System.nanoTime() - startTime;
        double secs = ((double)elapsed) / NPS;
        System.out.printf("\tTime: %7.3f\n", secs);
    }

}