content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.arrow.vector.dictionary;
  
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Random;
  import java.util.concurrent.TimeUnit;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.memory.RootAllocator;
  import org.apache.arrow.vector.ValueVector;
  import org.apache.arrow.vector.VarCharVector;
  import org.apache.arrow.vector.types.pojo.DictionaryEncoding;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.BenchmarkMode;
  import org.openjdk.jmh.annotations.Mode;
  import org.openjdk.jmh.annotations.OutputTimeUnit;
  import org.openjdk.jmh.annotations.Scope;
  import org.openjdk.jmh.annotations.Setup;
  import org.openjdk.jmh.annotations.State;
  import org.openjdk.jmh.annotations.TearDown;
  import org.openjdk.jmh.runner.Runner;
  import org.openjdk.jmh.runner.RunnerException;
  import org.openjdk.jmh.runner.options.Options;
  import org.openjdk.jmh.runner.options.OptionsBuilder;
  
  /** Benchmarks for {@link DictionaryEncoder}. */
  @State(Scope.Benchmark)
  public class DictionaryEncoderBenchmarks {
  
    private BufferAllocator allocator;
  
    private static final int DATA_SIZE = 1000;
    private static final int KEY_SIZE = 100;
  
    private static final int KEY_LENGTH = 10;
  
    private List<String> keys = new ArrayList<>();
  
    private VarCharVector vector;
  
    private VarCharVector dictionaryVector;
  
    /** Setup benchmarks. */
    @Setup
    public void prepare() {
  
      for (int i = 0; i < KEY_SIZE; i++) {
        keys.add(generateUniqueKey(KEY_LENGTH));
      }
  
      allocator = new RootAllocator(10 * 1024 * 1024);
  
      vector = new VarCharVector("vector", allocator);
      dictionaryVector = new VarCharVector("dict", allocator);
  
      vector.allocateNew(10240, DATA_SIZE);
      vector.setValueCount(DATA_SIZE);
      for (int i = 0; i < DATA_SIZE; i++) {
        byte[] value = keys.get(generateRandomIndex(KEY_SIZE)).getBytes(StandardCharsets.UTF_8);
        vector.setSafe(i, value, 0, value.length);
      }
  
      dictionaryVector.allocateNew(1024, 100);
      dictionaryVector.setValueCount(100);
      for (int i = 0; i < KEY_SIZE; i++) {
        byte[] value = keys.get(i).getBytes(StandardCharsets.UTF_8);
        dictionaryVector.setSafe(i, value, 0, value.length);
      }
    }
  
    /** Tear down benchmarks. */
    @TearDown
    public void tearDown() {
      vector.close();
      dictionaryVector.close();
      keys.clear();
      allocator.close();
    }
  
    /**
     * Test encode for {@link DictionaryEncoder}.
     *
     * @return useless. To avoid DCE by JIT.
     */
    @Benchmark
    @BenchmarkMode(Mode.AverageTime)
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public int testEncode() {
      Dictionary dictionary =
          new Dictionary(dictionaryVector, new DictionaryEncoding(1L, false, null));
      final ValueVector encoded = DictionaryEncoder.encode(vector, dictionary);
      encoded.close();
      return 0;
    }
  
    private int generateRandomIndex(int max) {
      Random random = new Random();
      return random.nextInt(max);
    }
  
    private String generateUniqueKey(int length) {
      String str = "abcdefghijklmnopqrstuvwxyz";
      Random random = new Random();
      StringBuffer sb = new StringBuffer();
      for (int i = 0; i < length; i++) {
        int number = random.nextInt(26);
        sb.append(str.charAt(number));
      }
      if (keys.contains(sb.toString())) {
        return generateUniqueKey(length);
      }
      return sb.toString();
    }
  
    public static void main(String[] args) throws RunnerException {
      Options opt =
          new OptionsBuilder()
              .include(DictionaryEncoderBenchmarks.class.getSimpleName())
              .forks(1)
              .build();
  
      new Runner(opt).run();
    }
  }
  