content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package com.google.common.util.concurrent;
  
  import static java.util.concurrent.TimeUnit.MILLISECONDS;
  
  import com.google.common.util.concurrent.RateLimiter.SleepingStopwatch;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  
  /**
   * Provides a fake {@link RateLimiter} to facilitate testing. Note that in Guava 14.0 the
   * {@link RateLimiter.SleepingStopwatch} class is package private, so this fake rate limiter has to
   * be in the same package to be able to extend it. Later versions of Guava makes it public, so this
   * can be moved to a package belongs to alluxio when updating to a newer version of Guava.
   */
  public final class MockRateLimiter {
    private final RateLimiter mRateLimiter;
    private final FakeSleepingTicker mTicker;
  
    /**
     * Constructs {@link MockRateLimiter}.
     *
     * @param permitsPerSecond the rate of the returned {@code RateLimiter}, measured in
     *        how many permits become available per second
     */
    public MockRateLimiter(double permitsPerSecond) {
      mTicker = new FakeSleepingTicker();
      mRateLimiter = RateLimiter.create(permitsPerSecond, mTicker);
    }
  
    /**
     * Gets Guava RateLimiter.
     *
     * @return Guava RateLimiter
     */
    public RateLimiter getGuavaRateLimiter() {
      return mRateLimiter;
    }
  
    /**
     * Sleeps in milliseconds.
     *
     * @param millis the number of milliseconds
     */
    public void sleepMillis(int millis) {
      mTicker.sleepMillis(millis);
    }
  
    /**
     * Reads events and clears.
     * @return the list of events
     */
    public List<String> readEventsAndClear() {
      return mTicker.readEventsAndClear();
    }
  
    /**
     * The sleeping ticker gathers events and presents them as strings.
     * R0.6 means a delay of 0.6 seconds caused by the (R)ateLimiter
     * U1.0 means the (U)ser caused the ticker to sleep for a second.
     */
    private static class FakeSleepingTicker extends SleepingStopwatch {
      private long mInstantMicros = 0L;
      private final List<String> mEvents = new ArrayList<>();
  
      @Override
      public long readMicros() {
        return mInstantMicros;
      }
  
      private void sleepMillis(int millis) {
        sleepMicros("U", MILLISECONDS.toMicros(millis));
      }
  
      private void sleepMicros(String caption, long micros) {
        mInstantMicros += micros;
        mEvents.add(caption + String.format(Locale.ROOT, "%3.2f", (micros / 1000000.0)));
      }
  
      @Override
      public void sleepMicrosUninterruptibly(long micros) {
        sleepMicros("R", micros);
      }
  
      private List<String> readEventsAndClear() {
        try {
          return new ArrayList<>(mEvents);
        } finally {
          mEvents.clear();
        }
      }
  
      @Override
      public String toString() {
        return mEvents.toString();
      }
    }
  }
  