/*

 * Copyright (c) 2014 Oracle and/or its affiliates. All rights reserved.

 * 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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 */

package org.openjdk.bench.java.util.stream;

import org.openjdk.jmh.annotations.Benchmark;

import org.openjdk.jmh.annotations.BenchmarkMode;

import org.openjdk.jmh.annotations.Mode;

import org.openjdk.jmh.annotations.OutputTimeUnit;

import org.openjdk.jmh.annotations.Param;

import org.openjdk.jmh.annotations.Scope;

import org.openjdk.jmh.annotations.Setup;

import org.openjdk.jmh.annotations.State;

import java.util.concurrent.TimeUnit;

import java.util.function.LongBinaryOperator;

import java.util.stream.LongStream;

/**

 * Benchmark for checking different reduce schemes.

 */

@BenchmarkMode(Mode.Throughput)

@OutputTimeUnit(TimeUnit.SECONDS)

@State(Scope.Thread)

public class Reducers {

    /**

     * Implementation notes:

     *   - parallel version requires thread-safe sink, we use the same for sequential version for better comparison

     *   - operations are explicit inner classes to untangle unwanted lambda effects

     *   - the result of applying consecutive operations is the same, in order to have the same number of elements in sink

     */

    @Param("100000")

    private int size;

    private LongBinaryOperator op;

    @Setup

    public void setup() {

        op = new LongBinaryOperator() {

            @Override

            public long applyAsLong(long l, long r) {

                return (l > r) ? l : r;

            }

        };

    }

    @Benchmark

    public long seq_reduce() {

        return LongStream.range(0, size).reduce(op).getAsLong();

    }

    @Benchmark

    public long par_reduce() {

        return LongStream.range(0, size).parallel().reduce(op).getAsLong();

    }

    @Benchmark

    public long seq_reduce_base() {

        return LongStream.range(0, size).reduce(0L, op);

    }

    @Benchmark

    public long par_reduce_base() {

        return LongStream.range(0, size).parallel().reduce(0L, op);

    }

}