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| 1 | +// understandingcollections/jmhtests/MapPerformance.java |
| 2 | +// (c)2016 MindView LLC: see Copyright.txt |
| 3 | +// We make no guarantees that this code is fit for any purpose. |
| 4 | +// Visit http://mindviewinc.com/Books/OnJava/ for more book information. |
| 5 | +// Performance differences between Maps |
| 6 | +package understandingcollections.jmhtests; |
| 7 | +import org.openjdk.jmh.annotations.*; |
| 8 | +import org.openjdk.jmh.infra.Blackhole; |
| 9 | +import java.util.*; |
| 10 | +import static java.util.concurrent.TimeUnit.*; |
| 11 | + |
| 12 | +@State(Scope.Thread) |
| 13 | +@Warmup(iterations = 5, time = 1, timeUnit = SECONDS) |
| 14 | +@Measurement(iterations = 5, time = 1, timeUnit = SECONDS) |
| 15 | +@Fork(1) |
| 16 | +@BenchmarkMode(Mode.AverageTime) |
| 17 | +@OutputTimeUnit(NANOSECONDS) |
| 18 | +public class MapPerformance { |
| 19 | + private Map<Integer, Integer> map; |
| 20 | + |
| 21 | + @Param({"hashmap", "treemap", "linkedhashmap", |
| 22 | + "identityhashmap", "weakhashmap", "hashtable"}) |
| 23 | + private String type; |
| 24 | + |
| 25 | + private int begin; |
| 26 | + private int end; |
| 27 | + |
| 28 | + @Setup |
| 29 | + public void setup() { |
| 30 | + switch(type) { |
| 31 | + case "hashmap": |
| 32 | + map = new HashMap<>(); |
| 33 | + break; |
| 34 | + case "treemap": |
| 35 | + map = new TreeMap<>(); |
| 36 | + break; |
| 37 | + case "linkedhashmap": |
| 38 | + map = new LinkedHashMap<>(); |
| 39 | + break; |
| 40 | + case "identityhashmap": |
| 41 | + map = new IdentityHashMap<>(); |
| 42 | + break; |
| 43 | + case "weakhashmap": |
| 44 | + map = new WeakHashMap<>(); |
| 45 | + break; |
| 46 | + case "hashtable": |
| 47 | + map = new Hashtable<>(); |
| 48 | + break; |
| 49 | + default: |
| 50 | + throw new IllegalStateException("Unknown " + type); |
| 51 | + } |
| 52 | + |
| 53 | + begin = 1; |
| 54 | + end = 256; |
| 55 | + for (int i = begin; i < end; i++) { |
| 56 | + map.put(i, i); |
| 57 | + } |
| 58 | + } |
| 59 | + |
| 60 | + @Benchmark |
| 61 | + public void get(Blackhole bh) { |
| 62 | + for (int i = begin; i < end; i++) { |
| 63 | + bh.consume(map.get(i)); |
| 64 | + } |
| 65 | + } |
| 66 | + |
| 67 | + @Benchmark |
| 68 | + public void put(Blackhole bh) { |
| 69 | + for (int i = begin; i < end; i++) { |
| 70 | + bh.consume(map.put(i, i)); |
| 71 | + } |
| 72 | + } |
| 73 | + |
| 74 | + @Benchmark |
| 75 | + public void iterate(Blackhole bh) { |
| 76 | + Iterator it = map.entrySet().iterator(); |
| 77 | + while(it.hasNext()) |
| 78 | + bh.consume(it.next()); |
| 79 | + } |
| 80 | + |
| 81 | +} |
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