/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Written by Doug Lea with assistance from members of JCP JSR-166

 * Expert Group and released to the public domain, as explained at

 */

/*

 * @test

 * @bug 4486658

 * @compile -source 1.5 LockOncePerThreadLoops.java

 * @run main/timeout=15000 LockOncePerThreadLoops

 * @summary Checks for missed signals by locking and unlocking each of an array of locks once per thread

 */

import java.util.concurrent.*;

import java.util.concurrent.locks.*;

import java.util.*;

public final class LockOncePerThreadLoops {

    static final ExecutorService pool = Executors.newCachedThreadPool();

    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();

    static boolean print = false;

    static int nlocks = 50000;

    static int nthreads = 100;

    static int replications = 5;

    public static void main(String[] args) throws Exception {

        if (args.length > 0)

            replications = Integer.parseInt(args[0]);

        if (args.length > 1)

            nlocks = Integer.parseInt(args[1]);

        print = true;

        for (int i = 0; i < replications; ++i) {

            System.out.print("Iteration: " + i);

            new ReentrantLockLoop().test();

            Thread.sleep(100);

        }

        pool.shutdown();

        if (! pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS))

            throw new Error();

    }

    static final class ReentrantLockLoop implements Runnable {

        private int v = rng.next();

        private volatile int result = 17;

        final ReentrantLock[]locks = new ReentrantLock[nlocks];

        private final ReentrantLock lock = new ReentrantLock();

        private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();

        private final CyclicBarrier barrier;

        ReentrantLockLoop() {

            barrier = new CyclicBarrier(nthreads+1, timer);

            for (int i = 0; i < nlocks; ++i)

                locks[i] = new ReentrantLock();

        }

        final void test() throws Exception {

            for (int i = 0; i < nthreads; ++i)

                pool.execute(this);

            barrier.await();

            barrier.await();

            if (print) {

                long time = timer.getTime();

                double secs = (double)(time) / 1000000000.0;

                System.out.println("\t " + secs + "s run time");

            }

            int r = result;

            if (r == 0) // avoid overoptimization

                System.out.println("useless result: " + r);

        }

        public final void run() {

            try {

                barrier.await();

                int sum = v;

                int x = 0;

                for (int i = 0; i < locks.length; ++i) {

                    locks[i].lock();

                    try {

                            v = x += ~(v - i);

                    }

                    finally {

                        locks[i].unlock();

                    }

                    // Once in a while, do something more expensive

                    if ((~i & 255) == 0) {

                        sum += LoopHelpers.compute1(LoopHelpers.compute2(x));

                    }

                    else

                        sum += sum ^ x;

                }

                barrier.await();

                result += sum;

            }

            catch (Exception ie) {

                return;

            }

        }

    }

}