77 lines
1.9 KiB
Java
77 lines
1.9 KiB
Java
// understandingcollections/jmh/Maps.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
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// Performance differences between Maps
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package understandingcollections.jmh;
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import org.openjdk.jmh.annotations.*;
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import org.openjdk.jmh.infra.Blackhole;
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import java.util.*;
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import static java.util.concurrent.TimeUnit.*;
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@State(Scope.Thread)
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@Warmup(iterations = 5, time = 1, timeUnit = SECONDS)
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@Measurement(iterations = 5, time = 1, timeUnit = SECONDS)
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@Fork(1)
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(MICROSECONDS)
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public class Maps {
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private Map<Integer, Integer> map;
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@Param({"HashMap", "TreeMap", "LinkedHashMap",
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"IdentityHashMap", "WeakHashMap", "Hashtable",})
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private String type;
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private int begin;
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private int end;
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@Setup
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public void setup() {
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switch(type) {
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case "HashMap":
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map = new HashMap<>();
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break;
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case "TreeMap":
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map = new TreeMap<>();
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break;
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case "LinkedHashMap":
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map = new LinkedHashMap<>();
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break;
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case "IdentityHashMap":
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map = new IdentityHashMap<>();
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break;
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case "WeakHashMap":
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map = new WeakHashMap<>();
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break;
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case "Hashtable":
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map = new Hashtable<>();
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break;
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default:
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throw new IllegalStateException("Unknown " + type);
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}
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begin = 1;
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end = 256;
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for (int i = begin; i < end; i++) {
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map.put(i, i);
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}
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}
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@Benchmark
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public void get(Blackhole bh) {
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for (int i = begin; i < end; i++) {
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bh.consume(map.get(i));
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}
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}
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@Benchmark
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public void put() {
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for (int i = begin; i < end; i++) {
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map.put(i, i);
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}
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}
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@Benchmark
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public void iterate(Blackhole bh) {
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Iterator it = map.entrySet().iterator();
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while(it.hasNext())
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bh.consume(it.next());
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}
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}
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