/*
* Copyright (C) 2010 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import com.google.caliper.Param;
import com.google.caliper.Runner;
import com.google.caliper.SimpleBenchmark;
import java.util.ArrayList;
import java.util.LinkedList;
/**
* Tests the speed of iteration of different iteration methods for collections.
*
* @author David Richter
*/
public class IteratorBenchmark extends SimpleBenchmark {
@Param({"0", "1", "16", "256", "4096", "65536"}) int size;
// use concrete classes to remove any possible polymorphic overhead?
Object[] array;
ArrayList<Object> arrayList;
LinkedList<Object> linkedList;
@Override protected void setUp() {
array = new Object[size];
arrayList = Lists.newArrayListWithCapacity(size);
linkedList = Lists.newLinkedList();
for (int i = 0; i < size; i++) {
Object value = new Object();
array[i] = value;
arrayList.add(value);
linkedList.add(value);
}
}
public int timeArrayIndexed(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (int index = 0; index < size; index++) {
sum += array[index].hashCode();
}
}
return sum;
}
public int timeArrayIndexedLength(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (int index = 0; index < array.length; index++) {
sum += array[index].hashCode();
}
}
return sum;
}
public int timeArrayFor(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (Object value : array) {
sum += value.hashCode();
}
}
return sum;
}
public int timeArrayListIndexed(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (int index = 0; index < size; index++) {
sum += arrayList.get(index).hashCode();
}
}
return sum;
}
public int timeArrayListIndexedLength(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (int index = 0; index < arrayList.size(); index++) {
sum += arrayList.get(index).hashCode();
}
}
return sum;
}
public int timeArrayListFor(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (Object value : arrayList) {
sum += value.hashCode();
}
}
return sum;
}
public int timeArrayListToArrayFor(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (Object value : arrayList.toArray()) {
sum += value.hashCode();
}
}
return sum;
}
public int timeLinkedListFor(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (Object value : linkedList) {
sum += value.hashCode();
}
}
return sum;
}
public int timeLinkedListToArrayFor(int reps) {
int sum = 0;
for (int i = 0; i < reps; i++) {
for (Object value : linkedList.toArray()) {
sum += value.hashCode();
}
}
return sum;
}
public static void main(String[] args) {
Runner.main(IteratorBenchmark.class, args);
}
}