1 /* 2 * Copyright (C) 2012 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.Benchmark; 20 import com.google.caliper.Param; 21 22 import java.util.List; 23 24 /** 25 * Benchmark for various ways to create an {@code ImmutableList}. 26 * 27 * @author Louis Wasserman 28 */ 29 public class ImmutableListCreationBenchmark { 30 31 @Param({"10", "1000", "1000000"}) 32 int size; 33 34 private static final Object OBJECT = new Object(); 35 36 @Benchmark int builderAdd(int reps) { 37 int size = this.size; 38 int dummy = 0; 39 for (int rep = 0; rep < reps; rep++) { 40 ImmutableList.Builder<Object> builder = ImmutableList.builder(); 41 for (int i = 0; i < size; i++) { 42 builder.add(OBJECT); 43 } 44 dummy += builder.build().size(); 45 } 46 return dummy; 47 } 48 49 @Benchmark int preSizedBuilderAdd(int reps) { 50 int size = this.size; 51 int dummy = 0; 52 for (int rep = 0; rep < reps; rep++) { 53 ImmutableList.Builder<Object> builder = new ImmutableList.Builder<Object>(size); 54 for (int i = 0; i < size; i++) { 55 builder.add(OBJECT); 56 } 57 dummy += builder.build().size(); 58 } 59 return dummy; 60 } 61 62 @Benchmark int copyArrayList(int reps) { 63 int size = this.size; 64 int dummy = 0; 65 for (int rep = 0; rep < reps; rep++) { 66 List<Object> builder = Lists.newArrayList(); 67 for (int i = 0; i < size; i++) { 68 builder.add(OBJECT); 69 } 70 dummy += ImmutableList.copyOf(builder).size(); 71 } 72 return dummy; 73 } 74 75 @Benchmark int copyPreSizedArrayList(int reps) { 76 int size = this.size; 77 int tmp = 0; 78 for (int rep = 0; rep < reps; rep++) { 79 List<Object> builder = Lists.newArrayListWithCapacity(size); 80 for (int i = 0; i < size; i++) { 81 builder.add(OBJECT); 82 } 83 tmp += ImmutableList.copyOf(builder).size(); 84 } 85 return tmp; 86 } 87 } 88
