MapBenchmark.java
package benchmark;
import com.google.common.collect.ImmutableMap;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
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 org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Random;
@State(Scope.Benchmark)
@Warmup(iterations = 2, time = 1)
@Measurement(iterations = 3, time = 1, batchSize = 1000)
@Fork(2)
public class MapBenchmark {
@Param({"10", "50", "300"})
int numberEntries = 300;
Map<String, Integer> hashMap;
Map<String, Integer> linkedHashMap;
Map<String, Integer> immutableMap;
Random random;
@Setup(Level.Trial)
public void setUp() {
random = new Random();
linkedHashMap = new LinkedHashMap<>();
for (int i = 0; i < numberEntries; i++) {
linkedHashMap.put("string" + i, i);
}
hashMap = new HashMap<>();
for (int i = 0; i < numberEntries; i++) {
hashMap.put("string" + i, i);
}
ImmutableMap.Builder<String, Integer> builder = ImmutableMap.builder();
for (int i = 0; i < numberEntries; i++) {
builder.put("string" + i, i);
}
immutableMap = builder.build();
}
@Benchmark
@BenchmarkMode(Mode.Throughput)
public void benchmarkLinkedHashMap(Blackhole blackhole) {
mapGet(blackhole, linkedHashMap);
}
@Benchmark
@BenchmarkMode(Mode.Throughput)
public void benchmarkHashMap(Blackhole blackhole) {
mapGet(blackhole, hashMap);
}
@Benchmark
@BenchmarkMode(Mode.Throughput)
public void benchmarkImmutableMap(Blackhole blackhole) {
mapGet(blackhole, immutableMap);
}
private void mapGet(Blackhole blackhole, Map<String, Integer> mapp) {
int index = rand(0, numberEntries);
blackhole.consume(mapp.get("string" + index));
}
private int rand(int loInc, int hiExc) {
return random.nextInt(hiExc - loInc) + loInc;
}
public static void main(String[] args) throws Exception {
Options opt = new OptionsBuilder()
.include("benchmark.MapBenchmark")
.build();
new Runner(opt).run();
}
}