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Java example source code file (MapBenchmark.java)

This example Java source code file (MapBenchmark.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

benchmark, collectionbenchmarksampledata, concurrenthashmap, element, hash, immutable, impl, linkedhm, map, mapmaker, mapmaker1, mapmaker16, override, param, threading, threads, util

The MapBenchmark.java Java example source code

/*
 * 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 static com.google.common.collect.Lists.newArrayList;

import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.common.collect.CollectionBenchmarkSampleData.Element;

import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentSkipListMap;

/**
 * A microbenchmark that tests the performance of get() and iteration on various map
 * implementations.  Forked from {@link SetContainsBenchmark}.
 *
 * @author Nicholaus Shupe
 */
public class MapBenchmark {
  @Param({"Hash", "LinkedHM", "MapMaker1", "Immutable"})
  private Impl impl;

  public enum Impl {
    Hash {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map = Maps.newHashMap();
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    LinkedHM {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map = Maps.newLinkedHashMap();
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    UnmodHM {
      @Override Map<Element, Element> create(Collection keys) {
        return Collections.unmodifiableMap(Hash.create(keys));
      }
    },
    SyncHM {
      @Override Map<Element, Element> create(Collection keys) {
        return Collections.synchronizedMap(Hash.create(keys));
      }
    },
    Tree {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map = Maps.newTreeMap();
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    SkipList {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map = new ConcurrentSkipListMap();
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    ConcurrentHM1 {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map =
            new ConcurrentHashMap<Element, Element>(keys.size(), 0.75f, 1);
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    ConcurrentHM16 {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map =
            new ConcurrentHashMap<Element, Element>(keys.size(), 0.75f, 16);
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    MapMaker1 {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map = new MapMaker()
            .concurrencyLevel(1)
            .makeMap();
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    MapMaker16 {
      @Override Map<Element, Element> create(Collection keys) {
        Map<Element, Element> map = new MapMaker()
            .concurrencyLevel(16)
            .makeMap();
        for (Element element: keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    Immutable {
      @Override Map<Element, Element> create(Collection keys) {
        ImmutableMap.Builder<Element, Element> builder = ImmutableMap.builder();
        for (Element element : keys) {
          builder.put(element, element);
        }
        return builder.build();
      }
    },
    ImmutableSorted {
      @Override Map<Element, Element> create(Collection keys) {
        ImmutableSortedMap.Builder<Element, Element> builder =
            ImmutableSortedMap.naturalOrder();
        for (Element element : keys) {
          builder.put(element, element);
        }
        return builder.build();
      }
    };

    abstract Map<Element, Element> create(Collection contents);
  }

  @Param({"5", "50", "500", "5000", "50000"})
  private int size;

  // TODO: look at exact (==) hits vs. equals() hits?
  @Param("0.9")
  private double hitRate;

  @Param("true")
  private boolean isUserTypeFast;

  // "" means no fixed seed
  @Param("")
  private SpecialRandom random;

  @Param("false")
  private boolean sortedData;

  // the following must be set during setUp
  private Element[] queries;
  private Map<Element, Element> mapToTest;

  private Collection<Element> values;

  @BeforeExperiment void setUp() {
    CollectionBenchmarkSampleData sampleData =
        new CollectionBenchmarkSampleData(
            isUserTypeFast, random, hitRate, size);

    if (sortedData) {
      List<Element> valueList = newArrayList(sampleData.getValuesInSet());
      Collections.sort(valueList);
      values = valueList;
    } else {
      values = sampleData.getValuesInSet();
    }
    this.mapToTest = impl.create(values);
    this.queries = sampleData.getQueries();
  }

  @Benchmark boolean get(int reps) {
    // Paranoia: acting on hearsay that accessing fields might be slow
    // Should write a benchmark to test that!
    Map<Element, Element> map = mapToTest;
    Element[] queries = this.queries;

    // Allows us to use & instead of %, acting on hearsay that division
    // operators (/%) are disproportionately expensive; should test this too!
    int mask = queries.length - 1;

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      dummy ^= map.get(queries[i & mask]) != null;
    }
    return dummy;
  }

  @Benchmark int createAndPopulate(int reps) {
    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += impl.create(values).size();
    }
    return dummy;
  }

  @Benchmark boolean iterateWithEntrySet(int reps) {
    Map<Element, Element> map = mapToTest;

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      for (Map.Entry<Element, Element> entry : map.entrySet()) {
        dummy ^= entry.getKey() != entry.getValue();
      }
    }
    return dummy;
  }

  @Benchmark boolean iterateWithKeySetAndGet(int reps) {
    Map<Element, Element> map = mapToTest;

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      for (Element key : map.keySet()) {
        Element value = map.get(key);
        dummy ^= key != value;
      }
    }
    return dummy;

  }
}

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