FJPool.java

/*
 * Apache License
 * Version 2.0, January 2004
 * http://www.apache.org/licenses/
 *
 *    Copyright 2013 Aurelian Tutuianu
 *    Copyright 2014 Aurelian Tutuianu
 *    Copyright 2015 Aurelian Tutuianu
 *    Copyright 2016 Aurelian Tutuianu
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 *
 */

package rapaio.util;

import java.util.Optional;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.function.Consumer;
import java.util.stream.IntStream;

/**
 * fork join pool utility
 * <p>
 * Created by <a href="mailto:padreati@yahoo.com">Aurelian Tutuianu</a> on 9/23/15.
 */
public class FJPool {

    public static void runRangeParallel(int start, int end, Consumer<Integer> r) {
        ForkJoinPool pool = new ForkJoinPool(Runtime.getRuntime().availableProcessors());
        Optional.of(pool.submit(() -> IntStream.range(start, end).parallel().forEach(r::accept)));
    }

    public static <T> Optional<T> compute(int threads, Callable<T> r) {
        ForkJoinPool pool = new ForkJoinPool(threads);
        try {
            return Optional.of(pool.submit(r::call).get());
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
            return Optional.empty();
        }
    }

    public static void run(int threads, Runnable r) {
        ForkJoinPool pool = new ForkJoinPool(threads);
        try {
            pool.submit(r).get();
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        }
    }
}