1 /* 2 * Copyright (C) 2010 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.collect; 18 19 import com.google.caliper.BeforeExperiment; 20 import com.google.caliper.Benchmark; 21 import com.google.caliper.Param; 22 23 import java.util.ArrayList; 24 import java.util.LinkedList; 25 26 /** 27 * Tests the speed of iteration of different iteration methods for collections. 28 * 29 * @author David Richter 30 */ 31 public class IteratorBenchmark { 32 @Param({"0", "1", "16", "256", "4096", "65536"}) int size; 33 34 // use concrete classes to remove any possible polymorphic overhead? 35 Object[] array; 36 ArrayList<Object> arrayList; 37 LinkedList<Object> linkedList; 38 39 @BeforeExperiment void setUp() { 40 array = new Object[size]; 41 arrayList = Lists.newArrayListWithCapacity(size); 42 linkedList = Lists.newLinkedList(); 43 44 for (int i = 0; i < size; i++) { 45 Object value = new Object(); 46 array[i] = value; 47 arrayList.add(value); 48 linkedList.add(value); 49 } 50 } 51 52 @Benchmark int arrayIndexed(int reps) { 53 int sum = 0; 54 for (int i = 0; i < reps; i++) { 55 for (int index = 0; index < size; index++) { 56 sum += array[index].hashCode(); 57 } 58 } 59 return sum; 60 } 61 62 @Benchmark int arrayIndexedLength(int reps) { 63 int sum = 0; 64 for (int i = 0; i < reps; i++) { 65 for (int index = 0; index < array.length; index++) { 66 sum += array[index].hashCode(); 67 } 68 } 69 return sum; 70 } 71 72 @Benchmark int arrayFor(int reps) { 73 int sum = 0; 74 for (int i = 0; i < reps; i++) { 75 for (Object value : array) { 76 sum += value.hashCode(); 77 } 78 } 79 return sum; 80 } 81 82 @Benchmark int arrayListIndexed(int reps) { 83 int sum = 0; 84 for (int i = 0; i < reps; i++) { 85 for (int index = 0; index < size; index++) { 86 sum += arrayList.get(index).hashCode(); 87 } 88 } 89 return sum; 90 } 91 92 @Benchmark int arrayListIndexedLength(int reps) { 93 int sum = 0; 94 for (int i = 0; i < reps; i++) { 95 for (int index = 0; index < arrayList.size(); index++) { 96 sum += arrayList.get(index).hashCode(); 97 } 98 } 99 return sum; 100 } 101 102 @Benchmark int arrayListFor(int reps) { 103 int sum = 0; 104 for (int i = 0; i < reps; i++) { 105 for (Object value : arrayList) { 106 sum += value.hashCode(); 107 } 108 } 109 return sum; 110 } 111 112 @Benchmark int arrayListToArrayFor(int reps) { 113 int sum = 0; 114 for (int i = 0; i < reps; i++) { 115 for (Object value : arrayList.toArray()) { 116 sum += value.hashCode(); 117 } 118 } 119 return sum; 120 } 121 122 @Benchmark int linkedListFor(int reps) { 123 int sum = 0; 124 for (int i = 0; i < reps; i++) { 125 for (Object value : linkedList) { 126 sum += value.hashCode(); 127 } 128 } 129 return sum; 130 } 131 132 @Benchmark int linkedListToArrayFor(int reps) { 133 int sum = 0; 134 for (int i = 0; i < reps; i++) { 135 for (Object value : linkedList.toArray()) { 136 sum += value.hashCode(); 137 } 138 } 139 return sum; 140 } 141 } 142
