org.diorite.utils.concurrent.ParallelUtils.java Source code

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/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2016. Diorite (by Bartomiej Mazur (aka GotoFinal))
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package org.diorite.utils.concurrent;

import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinPool.ForkJoinWorkerThreadFactory;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.ForkJoinWorkerThread;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Supplier;

import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;

public final class ParallelUtils {
    private static final Runtime runtime = Runtime.getRuntime();

    private ParallelUtils() {
    }

    public static int getCores() {
        return runtime.availableProcessors();
    }

    public static void realParallelStream(final Runnable streamAction, final int parallelism) {
        realParallelStream(streamAction, parallelism, true);
    }

    public static void realParallelStream(final Runnable streamAction) {
        realParallelStream(streamAction, runtime.availableProcessors(), true);
    }

    public static void realParallelStream(final Runnable streamAction, final int parallelism, final boolean await) {
        final ForkJoinPool pool = new ForkJoinPool(parallelism);
        if (await) {
            pool.invoke(createSimpleTask(streamAction));
        } else {
            pool.submit(streamAction);
        }
    }

    public static void realParallelStream(final Runnable streamAction, final boolean await) {
        realParallelStream(streamAction, runtime.availableProcessors(), await);
    }

    public static <T> T realParallelStream(final Supplier<T> streamAction, final int parallelism) {
        final ForkJoinPool pool = new ForkJoinPool(parallelism);
        return pool.invoke(createTask(streamAction));
    }

    public static <T> T realParallelStream(final Supplier<T> streamAction) {
        return realParallelStream(streamAction, runtime.availableProcessors());
    }

    public static void realParallelStream(final Runnable streamAction, final int parallelism, final String name) {
        realParallelStream(streamAction, parallelism, true, name);
    }

    public static void realParallelStream(final Runnable streamAction, final String name) {
        realParallelStream(streamAction, runtime.availableProcessors(), true, name);
    }

    public static void realParallelStream(final Runnable streamAction, final int parallelism, final boolean await,
            final String name) {
        final ForkJoinPool pool = new ForkJoinPool(parallelism, new NamedForkJoinWorkerFactory(name), null, false);
        if (await) {
            pool.invoke(createSimpleTask(streamAction));
        } else {
            pool.submit(streamAction);
        }
    }

    public static void realParallelStream(final Runnable streamAction, final boolean await, final String name) {
        realParallelStream(streamAction, runtime.availableProcessors(), await, name);
    }

    public static <T> T realParallelStream(final Supplier<T> streamAction, final int parallelism,
            final String name) {
        final ForkJoinPool pool = new ForkJoinPool(parallelism, new NamedForkJoinWorkerFactory(name), null, false);
        return pool.invoke(createTask(streamAction));
    }

    public static <T> T realParallelStream(final Supplier<T> streamAction, final String name) {
        return realParallelStream(streamAction, runtime.availableProcessors(), name);
    }

    public static ForkJoinTask<Void> createSimpleTask(final Runnable runnable) {
        return new ForkJoinTask<Void>() {
            @Override
            public Void getRawResult() {
                return null;
            }

            @Override
            protected void setRawResult(final Void value) {
            }

            @Override
            protected boolean exec() {
                runnable.run();
                return true;
            }
        };
    }

    public static ForkJoinTask<Void> createSimpleTask(final Supplier<Boolean> runnable) {
        return new ForkJoinTask<Void>() {
            @Override
            public Void getRawResult() {
                return null;
            }

            @Override
            protected void setRawResult(final Void value) {
            }

            @Override
            protected boolean exec() {
                return runnable.get();
            }
        };
    }

    public static <T> ForkJoinTask<T> createTask(final Supplier<T> runnable) {
        return new ForkJoinTask<T>() {
            private T result;

            @Override
            public T getRawResult() {
                return this.result;
            }

            @Override
            protected void setRawResult(final T value) {
                this.result = value;
            }

            @Override
            protected boolean exec() {
                this.result = runnable.get();
                return true;
            }
        };
    }

    private static class NamedForkJoinWorkerThread extends ForkJoinWorkerThread {
        private NamedForkJoinWorkerThread(final ForkJoinPool pool, final String name) {
            super(pool);
            this.setName(name);
        }
    }

    public static class NamedForkJoinWorkerFactory implements ForkJoinWorkerThreadFactory {
        private final String baseName;
        private final AtomicInteger i = new AtomicInteger(0);

        public NamedForkJoinWorkerFactory(final String baseName) {
            this.baseName = baseName;
        }

        @Override
        public final ForkJoinWorkerThread newThread(final ForkJoinPool pool) {
            return new NamedForkJoinWorkerThread(pool, this.baseName + "-" + this.i.getAndIncrement());
        }

        @Override
        public String toString() {
            return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE).appendSuper(super.toString())
                    .append("baseName", this.baseName).append("i", this.i).toString();
        }
    }
}