* <p>Rate limiters are often used to restrict the rate at which some physical or logical resource
 * is accessed. This is in contrast to {@link java.util.concurrent.Semaphore} which restricts the
 * number of concurrent accesses instead of the rate (note though that concurrency and rate are
 * closely related, e.g. see <a href="http://en.wikipedia.org/wiki/Little%27s_law">Little's
 * Law</a>).
 *

   * we change the rate.
   */
  public void testWeNeverGetABurstMoreThanOneSec() {
    RateLimiter limiter = RateLimiter.create(1.0, stopwatch);
    int[] rates = {1000, 1, 10, 1000000, 10, 1};
    for (int rate : rates) {
      int oneSecWorthOfWork = rate;
      stopwatch.sleepMillis(rate * 1000);
      limiter.setRate(rate);

Rabbit with pink eyes ran close by her.

  There was nothing so VERY remarkable in that; nor did Alice
think it so VERY much out of the way to hear the Rabbit say to
itself, `Oh dear!  Oh dear!  I shall be late!'  (when she thought
it over afterwards, it occurred to her that she ought to have
wondered at this, but at the time it all seemed quite natural);
but when the Rabbit actually TOOK A WATCH OUT OF ITS WAISTCOAT-

        public String toString() {
          throw new AssertionFailedError();
        }
      };

  private static final String FORMAT = "I ate %s pies.";

  private static void checkMessage(Exception e) {
    assertThat(e).hasMessageThat().isEqualTo("I ate 5 pies.");
  }

   * out.
   */
  long timeoutMillis() {
    return SHORT_DELAY_MS / 4;
  }

  /** Returns a new Date instance representing a time delayMillis milliseconds in the future. */
  Date delayedDate(long delayMillis) {
    return new Date(System.currentTimeMillis() + delayMillis);
  }

  /** The first exception encountered if any threadAssertXXX method fails. */

  final Policy policy;

  private CycleDetectingLockFactory(Policy policy) {
    this.policy = checkNotNull(policy);
  }

  /**
   * Tracks the currently acquired locks for each Thread, kept up to date by calls to {@link
   * #aboutToAcquire(CycleDetectingLock)} and {@link #lockStateChanged(CycleDetectingLock)}.
   */
  // This is logically a Set, but an ArrayList is used to minimize the amount

   * underlying model is a continuous function mapping storedPermits (from 0.0 to maxStoredPermits)
   * onto the 1/rate (i.e. intervals) that is effective at the given storedPermits. "storedPermits"
   * essentially measure unused time; we spend unused time buying/storing permits. Rate is
   * "permits / time", thus "1 / rate = time / permits". Thus, "1/rate" (time / permits) times

 *       token attempt, one measure of the quality of a hash function is <i>how well</i> it succeeds
 *       at this goal. Important note: it may be easy to achieve the theoretical minimum collision
 *       rate when using completely <i>random</i> sample input. The true test of a hash function is
 *       how it performs on representative real-world data, which tends to contain many hidden

  int maximumSize;

  @Param("5000")
  int distinctKeys;

  @Param("4")
  int segments;

  // 1 means uniform likelihood of keys; higher means some keys are more popular
  // tweak this to control hit rate
  @Param("2.5")
  double concentration;

  Random random = new Random();

  LoadingCache<Integer, Integer> cache;

  int max;

  static AtomicLong requests = new AtomicLong(0);

   * out.
   */
  long timeoutMillis() {
    return SHORT_DELAY_MS / 4;
  }

  /** Returns a new Date instance representing a time delayMillis milliseconds in the future. */
  Date delayedDate(long delayMillis) {
    return new Date(System.currentTimeMillis() + delayMillis);
  }

  /** The first exception encountered if any threadAssertXXX method fails. */