_results.txt

Benchmark            (generator)  (length)  (postprocess)  Mode  Cnt  Score   Error  Units
ListIndexOf.indexOf       random   1000000           none  avgt   10  1,243 ± 0,031  ms/op
ListIndexOf.indexOf       random   1000000           sort  avgt   10  6,496 ± 0,456  ms/op
ListIndexOf.indexOf       random   1000000        shuffle  avgt   10  6,485 ± 0,412  ms/op
ListIndexOf.indexOf   sequential   1000000           none  avgt   10  1,249 ± 0,053  ms/op
ListIndexOf.indexOf   sequential   1000000           sort  avgt   10  1,247 ± 0,037  ms/op
ListIndexOf.indexOf   sequential   1000000        shuffle  avgt   10  6,579 ± 0,448  ms/op

ListIndexOf.java

package bench;

import org.openjdk.jmh.annotations.*;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

@State(Scope.Benchmark)
public class ListIndexOf {
    private static final Random random = new Random(0);

    @Param("1000000")
    private int length;

    @Param({"random", "sequential"})
    private String generator;

    @Param({"none", "sort", "shuffle"})
    private String postprocess;

    private List<Double> list;

    @Setup
    public void setup() {
        if ("random".equals(generator)) {
            list = random.doubles(length).boxed().collect(Collectors.toList());
        } else if ("sequential".equals(generator)) {
            list = IntStream.range(0, length).asDoubleStream().boxed().collect(Collectors.toList());
        }

        if ("sort".equals(postprocess)) {
            Collections.sort(list);
        } else if ("shuffle".equals(postprocess)) {
            Collections.shuffle(list);
        }
    }

    @Benchmark
    public int indexOf() {
        int index = random.nextInt(length);
        return list.indexOf(list.get(index));
    }
}