212 lines
6.8 KiB
Java
212 lines
6.8 KiB
Java
// collectionsindepth/ListPerformance.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 Lists
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// Small to keep build testing short:
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// {java ListPerformance 100 500}
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import java.util.*;
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import onjava.*;
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public class ListPerformance {
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static SplittableRandom rand = new SplittableRandom();
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static int reps = 1000;
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static List<Test<List<Integer>>> tests =
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new ArrayList<>();
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static List<Test<LinkedList<Integer>>> qTests =
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new ArrayList<>();
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static {
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tests.add(new Test<List<Integer>>("add") {
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@Override
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int test(List<Integer> list, TestParam tp) {
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int loops = tp.loops;
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int listSize = tp.size;
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for(int i = 0; i < loops; i++) {
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list.clear();
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for(int j = 0; j < listSize; j++)
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list.add(j);
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}
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return loops * listSize;
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}
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});
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tests.add(new Test<List<Integer>>("get") {
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@Override
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int test(List<Integer> list, TestParam tp) {
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int loops = tp.loops * reps;
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int listSize = list.size();
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for(int i = 0; i < loops; i++)
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list.get(rand.nextInt(listSize));
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return loops;
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}
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});
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tests.add(new Test<List<Integer>>("set") {
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@Override
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int test(List<Integer> list, TestParam tp) {
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int loops = tp.loops * reps;
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int listSize = list.size();
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for(int i = 0; i < loops; i++)
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list.set(rand.nextInt(listSize), 47);
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return loops;
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}
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});
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tests.add(new Test<List<Integer>>("iteradd") {
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@Override
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int test(List<Integer> list, TestParam tp) {
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final int LOOPS = 1000000;
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int half = list.size() / 2;
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ListIterator<Integer> it =
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list.listIterator(half);
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for(int i = 0; i < LOOPS; i++)
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it.add(47);
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return LOOPS;
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}
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});
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tests.add(new Test<List<Integer>>("insert") {
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@Override
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int test(List<Integer> list, TestParam tp) {
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int loops = tp.loops;
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for(int i = 0; i < loops; i++)
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list.add(5, 47); // Minimize random-access cost
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return loops;
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}
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});
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tests.add(new Test<List<Integer>>("remove") {
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@Override
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int test(List<Integer> list, 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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list.clear();
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list.addAll(new CountingIntegerList(size));
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while(list.size() > 5)
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list.remove(5); // Minimize random-access cost
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}
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return loops * size;
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}
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});
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// Tests for queue behavior:
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qTests.add(new Test<LinkedList<Integer>>("addFirst") {
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@Override
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int test(LinkedList<Integer> list, 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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list.clear();
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for(int j = 0; j < size; j++)
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list.addFirst(47);
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}
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return loops * size;
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}
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});
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qTests.add(new Test<LinkedList<Integer>>("addLast") {
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@Override
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int test(LinkedList<Integer> list, 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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list.clear();
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for(int j = 0; j < size; j++)
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list.addLast(47);
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}
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return loops * size;
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}
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});
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qTests.add(
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new Test<LinkedList<Integer>>("rmFirst") {
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@Override
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int test(LinkedList<Integer> list, 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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list.clear();
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list.addAll(new CountingIntegerList(size));
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while(list.size() > 0)
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list.removeFirst();
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}
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return loops * size;
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}
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});
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qTests.add(new Test<LinkedList<Integer>>("rmLast") {
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@Override
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int test(LinkedList<Integer> list, 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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list.clear();
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list.addAll(new CountingIntegerList(size));
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while(list.size() > 0)
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list.removeLast();
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}
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return loops * size;
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}
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});
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}
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static class ListTester extends Tester<List<Integer>> {
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public ListTester(List<Integer> collection,
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List<Test<List<Integer>>> tests) {
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super(collection, tests);
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}
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// Fill to the appropriate size before each test:
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@Override
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protected List<Integer> initialize(int size) {
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collection.clear();
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collection.addAll(new CountingIntegerList(size));
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return collection;
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}
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// Convenience method:
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public static void run(List<Integer> list,
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List<Test<List<Integer>>> tests) {
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new ListTester(list, tests).timedTest();
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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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// Can only do these two tests on an array:
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Tester<List<Integer>> arrayTest =
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new Tester<List<Integer>>(null,
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tests.subList(1, 3)) {
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// This is called before each test. It
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// produces a non-resizeable array-backed list:
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@Override protected
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List<Integer> initialize(int size) {
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Integer[] ia = new Integer[size];
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Arrays.setAll(ia, new Count.Integer()::get);
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return Arrays.asList(ia);
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}
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};
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arrayTest.setHeadline("Array as List");
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arrayTest.timedTest();
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Tester.defaultParams= TestParam.array(
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10, 5000, 100, 5000, 1000, 1000, 10000, 200);
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if(args.length > 0)
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Tester.defaultParams = TestParam.array(args);
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ListTester.run(new ArrayList<>(), tests);
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ListTester.run(new LinkedList<>(), tests);
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ListTester.run(new Vector<>(), tests);
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Tester.fieldWidth = 12;
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Tester<LinkedList<Integer>> qTest =
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new Tester<LinkedList<Integer>>(
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new LinkedList<>(), qTests);
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qTest.setHeadline("Queue tests");
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qTest.timedTest();
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}
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}
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/* Output:
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--- Array as List ---
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size get set
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100 50 68
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--------------------- ArrayList ---------------------
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size add get set iteradd insert remove
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100 60 76 74 103 0 360
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--------------------- LinkedList ---------------------
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size add get set iteradd insert remove
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100 200 166 114 201 0 120
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----------------------- Vector -----------------------
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size add get set iteradd insert remove
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100 60 76 84 159 0 220
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-------------------- Queue tests --------------------
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size addFirst addLast rmFirst rmLast
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100 80 160 100 120
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*/
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