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.kafka.jmh.cache;
  
  import org.apache.kafka.common.cache.LRUCache;
  
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.Level;
  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.runner.Runner;
  import org.openjdk.jmh.runner.RunnerException;
  import org.openjdk.jmh.runner.options.Options;
  import org.openjdk.jmh.runner.options.OptionsBuilder;
  
  import java.util.concurrent.TimeUnit;
  
  /**
   * This is a simple example of a JMH benchmark.
   *
   * The sample code provided by the JMH project is a great place to start learning how to write correct benchmarks:
   * http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/
   */
  @State(Scope.Thread)
  @OutputTimeUnit(TimeUnit.MILLISECONDS)
  public class LRUCacheBenchmark {
  
      private static final int DISTINCT_KEYS = 10_000;
  
      private static final String KEY = "the_key_to_use";
  
      private static final String VALUE = "the quick brown fox jumped over the lazy dog the olympics are about to start";
  
      private final String[] keys = new String[DISTINCT_KEYS];
  
      private final String[] values = new String[DISTINCT_KEYS];
  
      private LRUCache<String, String> lruCache;
  
      private long counter = 0;
  
      @Setup(Level.Trial)
      public void setUp() {
          for (int i = 0; i < DISTINCT_KEYS; ++i) {
              keys[i] = KEY + i;
              values[i] = VALUE + i;
          }
          lruCache = new LRUCache<>(100);
      }
  
      @Benchmark
      public String testCachePerformance() {
          counter++;
          int index = (int) (counter % DISTINCT_KEYS);
          String hashkey = keys[index];
          lruCache.put(hashkey, values[index]);
          return lruCache.get(hashkey);
      }
  
      public static void main(String[] args) throws RunnerException {
          Options opt = new OptionsBuilder()
                  .include(LRUCacheBenchmark.class.getSimpleName())
                  .forks(2)
                  .build();
  
          new Runner(opt).run();
      }
  
  }
  