/*
    * Copyright (C) 2012 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.Benchmark;
  import com.google.caliper.Param;
  
  import java.util.List;
  
  /**
   * Benchmark for various ways to create an {@code ImmutableList}.
   *
   * @author Louis Wasserman
   */
  public class ImmutableListCreationBenchmark {
  
    @Param({"10", "1000", "1000000"})
    int size;
  
    private static final Object OBJECT = new Object();
  
    @Benchmark int builderAdd(int reps) {
      int size = this.size;
      int dummy = 0;
      for (int rep = 0; rep < reps; rep++) {
        ImmutableList.Builder<Object> builder = ImmutableList.builder();
        for (int i = 0; i < size; i++) {
          builder.add(OBJECT);
        }
        dummy += builder.build().size();
      }
      return dummy;
    }
  
    @Benchmark int preSizedBuilderAdd(int reps) {
      int size = this.size;
      int dummy = 0;
      for (int rep = 0; rep < reps; rep++) {
        ImmutableList.Builder<Object> builder = new ImmutableList.Builder<Object>(size);
        for (int i = 0; i < size; i++) {
          builder.add(OBJECT);
        }
        dummy += builder.build().size();
      }
      return dummy;
    }
  
    @Benchmark int copyArrayList(int reps) {
      int size = this.size;
      int dummy = 0;
      for (int rep = 0; rep < reps; rep++) {
        List<Object> builder = Lists.newArrayList();
        for (int i = 0; i < size; i++) {
          builder.add(OBJECT);
        }
        dummy += ImmutableList.copyOf(builder).size();
      }
      return dummy;
    }
  
    @Benchmark int copyPreSizedArrayList(int reps) {
      int size = this.size;
      int tmp = 0;
      for (int rep = 0; rep < reps; rep++) {
        List<Object> builder = Lists.newArrayListWithCapacity(size);
        for (int i = 0; i < size; i++) {
          builder.add(OBJECT);
        }
        tmp += ImmutableList.copyOf(builder).size();
      }
      return tmp;
    }
  }