public long hitCount() {
    return hitCount;
  }

  /**
   * Returns the ratio of cache requests which were hits. This is defined as {@code hitCount /
   * requestCount}, or {@code 1.0} when {@code requestCount == 0}. Note that {@code hitRate +
   * missRate =~ 1.0}.
   */
  public double hitRate() {
    long requestCount = requestCount();
    return (requestCount == 0) ? 1.0 : (double) hitCount / requestCount;
  }