83 lines
2.4 KiB
Java
83 lines
2.4 KiB
Java
// collectionsindepth/MapPerformance.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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// Demonstrates performance differences in Maps
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// Small to keep build testing short:
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// {Args: 100 5000}
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import java.util.*;
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public class MapPerformance {
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static List<Test<Map<Integer,Integer>>> tests =
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new ArrayList<>();
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static {
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tests.add(new Test<Map<Integer,Integer>>("put") {
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@Override
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int test(Map<Integer,Integer> map, TestParam tp) {
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int loops = tp.loops;
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int size = tp.size;
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for(int i = 0; i < loops; i++) {
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map.clear();
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for(int j = 0; j < size; j++)
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map.put(j, j);
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}
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return loops * size;
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}
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});
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tests.add(new Test<Map<Integer,Integer>>("get") {
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@Override
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int test(Map<Integer,Integer> map, TestParam tp) {
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int loops = tp.loops;
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int span = tp.size * 2;
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for(int i = 0; i < loops; i++)
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for(int j = 0; j < span; j++)
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map.get(j);
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return loops * span;
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}
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});
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tests.add(new Test<Map<Integer,Integer>>("iterate") {
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@Override
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int test(Map<Integer,Integer> map, TestParam tp) {
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int loops = tp.loops * 10;
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for(int i = 0; i < loops; i ++) {
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Iterator it = map.entrySet().iterator();
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while(it.hasNext())
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it.next();
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}
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return loops * map.size();
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}
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});
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}
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public static void main(String[] args) {
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if(args.length > 0)
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Tester.defaultParams = TestParam.array(args);
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Tester.run(new TreeMap<>(), tests);
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Tester.run(new HashMap<>(), tests);
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Tester.run(new LinkedHashMap<>(),tests);
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Tester.run(
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new IdentityHashMap<>(), tests);
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Tester.run(new WeakHashMap<>(), tests);
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Tester.run(new Hashtable<>(), tests);
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}
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}
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/* Output:
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---------- TreeMap ----------
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size put get iterate
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100 86 47 9
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---------- HashMap ----------
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size put get iterate
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100 25 10 12
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------- LinkedHashMap -------
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size put get iterate
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100 27 8 6
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------ IdentityHashMap ------
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size put get iterate
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100 51 47 13
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-------- WeakHashMap --------
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size put get iterate
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100 28 11 12
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--------- Hashtable ---------
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size put get iterate
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100 31 21 13
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*/
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