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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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,
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package org.openjdk.bench.java.util.stream.tasks.IntegerDuplicate;

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.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;

import java.util.Arrays;
import java.util.Collections;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.LongAdder;

/**
 * This benchmark assesses flatMap() performance.
 */
@BenchmarkMode(Mode.Throughput)
@OutputTimeUnit(TimeUnit.SECONDS)
@State(Scope.Thread)
public class Lambda {

    /**
     * Implementation notes:
     *   - parallel versions need to use special sink to get the values
     */

    private IntegerDuplicateProblem problem;

    @Setup
    public void setup() {
        problem = new IntegerDuplicateProblem();
    }

    @Benchmark
    public long lambda_seq_inner() {
        return Arrays.stream(problem.get()).flatMap(k -> Collections.nCopies(2, k).stream())
                .collect(LongAdder::new, LongAdder::add, (la1, la2) -> la1.add(la2.sum())).sum();
    }

    @Benchmark
    public long lambda_par_inner() {
        return Arrays.stream(problem.get()).parallel().flatMap(k -> Collections.nCopies(2, k).stream())
                .collect(LongAdder::new, LongAdder::add, (la1, la2) -> la1.add(la2.sum())).sum();
    }

}