/*
    * 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.cache;
  
  import com.google.caliper.BeforeExperiment;
  import com.google.caliper.Benchmark;
  import com.google.common.base.Function;
  import com.google.common.base.Functions;
  import com.google.common.collect.MapMaker;
  
  import java.util.Map;
  
  /**
   * Compare CacheBuilder and MapMaker performance, ensuring that they remain on par with each other.
   *
   * @author Nikita Sidorov
   */
  public class MapMakerComparisonBenchmark {
    private static final String TEST_KEY = "test key";
    private static final String TEST_VALUE = "test value";
  
    private static final Function<Object, Object> IDENTITY = Functions.identity();
  
    // Loading/computing versions:
    private final Map<Object, Object> computingMap = new MapMaker().makeComputingMap(IDENTITY);
    private final LoadingCache<Object, Object> loadingCache =
        CacheBuilder.newBuilder().recordStats().build(CacheLoader.from(IDENTITY));
    private final LoadingCache<Object, Object> loadingCacheNoStats =
        CacheBuilder.newBuilder().build(CacheLoader.from(IDENTITY));
  
    // Non-loading versions:
    private final Map<Object, Object> map = new MapMaker().makeMap(); // Returns ConcurrentHashMap
    private final Cache<Object, Object> cache = CacheBuilder.newBuilder().recordStats().build();
    private final Cache<Object, Object> cacheNoStats = CacheBuilder.newBuilder().build();
  
    @BeforeExperiment
    void setUp() {
      map.put(TEST_KEY, TEST_VALUE);
      cache.put(TEST_KEY, TEST_VALUE);
      cacheNoStats.put(TEST_KEY, TEST_VALUE);
    }
  
    @Benchmark void computingMapMaker(int rep) {
      for (int i = 0; i < rep; i++) {
        computingMap.get(TEST_KEY);
      }
    }
  
    @Benchmark void loadingCacheBuilder_stats(int rep) {
      for (int i = 0; i < rep; i++) {
        loadingCache.getUnchecked(TEST_KEY);
      }
    }
  
    @Benchmark void loadingCacheBuilder(int rep) {
      for (int i = 0; i < rep; i++) {
        loadingCacheNoStats.getUnchecked(TEST_KEY);
      }
    }
  
    @Benchmark void concurrentHashMap(int rep) {
      for (int i = 0; i < rep; i++) {
        map.get(TEST_KEY);
      }
    }
  
    @Benchmark void cacheBuilder_stats(int rep) {
      for (int i = 0; i < rep; i++) {
        cache.getIfPresent(TEST_KEY);
      }
    }
  
    @Benchmark void cacheBuilder(int rep) {
      for (int i = 0; i < rep; i++) {
        cacheNoStats.getIfPresent(TEST_KEY);
      }
    }
  }