NullCheck.java

package org.jooq.test.benchmark;

import java.util.ArrayList;
import java.util.List;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;

@Fork(value = 3, jvmArgsAppend = "-Djmh.stack.lines=3")
@Warmup(iterations = 5)
@Measurement(iterations = 7)
public class NullCheck {

    @State(Scope.Benchmark)
    public static class BenchmarkState {

        List<Integer> list = new ArrayList<Integer>();

        @Setup(Level.Trial)
        public void setup() throws Exception {
            for (int i = 0; i < 100; i++)
                list.add(i);
        }

        @TearDown(Level.Trial)
        public void teardown() throws Exception {
            list = null;
        }
    }

    @Benchmark
    public void testNullAndEmptyCheck(Blackhole blackhole, BenchmarkState state) {
        if (state.list == null || state.list.isEmpty())
            return;

        for (Integer i : state.list)
            blackhole.consume(i);
    }

    @Benchmark
    public void testNoEmptyCheck(Blackhole blackhole, BenchmarkState state) {
        if (state.list == null)
            return;

        for (Integer i : state.list)
            blackhole.consume(i);
    }

    @Benchmark
    public void testNoCheck(Blackhole blackhole, BenchmarkState state) {
        for (Integer i : state.list)
            blackhole.consume(i);
    }
}