BenchmarkStreams.java

package com.mmimica;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.stream.Stream;
import org.openjdk.jmh.annotations.*;
 
@State(Scope.Benchmark)
@BenchmarkMode(Mode.Throughput)
@Warmup(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(1)
public class BenchmarkStreams {
    List<Integer> list = new ArrayList<>();
    
    @Param({ "1", "1000", "10000", "100000" })
    int size;
    
    @Setup
    public void setup() {
        for (int i = 0; i < size; i++)
            list.add(i);
    }
    
    private int find(Stream<Integer> stream) {
        return stream
                .filter(i -> i == -1)
                .findAny()
                .orElse(0);
    }
    
    @Benchmark
    public int parallel_stream() {
        return find(list.parallelStream());
    }
    
    @Benchmark
    public int stream() {
        return find(list.stream());
    }
    
    @Benchmark
    public int loop() {
        for (Integer i : list) {
            if (i == -1)
                return i;
        }
        return 0;
    }
}