}

  /**
   * @since 11.0
   */
  @Override
  // For discussion of <? extends Object>, see getAllPresent.
  public void invalidateAll(Iterable<? extends Object> keys) {
    delegate().invalidateAll(keys);
  }

  @Override
  public void invalidateAll() {
    delegate().invalidateAll();
  }

  @Override
  public long size() {
    return delegate().size();
  }

  @Override

  /**
   * @since 11.0
   */
  @Override
  // For discussion of <? extends Object>, see getAllPresent.
  public void invalidateAll(Iterable<? extends Object> keys) {
    for (Object key : keys) {
      invalidate(key);
    }
  }

  @Override
  public void invalidateAll() {
    throw new UnsupportedOperationException();
  }

  @Override
  public CacheStats stats() {

      Key key = new Key(1);
      String value = key.toString();
      assertThat(cache.getUnchecked(key)).isSameInstanceAs(value);
      assertThat(cache.asMap().isEmpty()).isFalse();
      cache.invalidateAll();
      assertThat(cache.size()).isEqualTo(0);
      assertThat(cache.asMap().isEmpty()).isTrue();
      assertThat(cache.asMap().containsKey(key)).isFalse();
      assertThat(cache.asMap().containsValue(value)).isFalse();

  /**
   * @since 11.0
   */
  @Override
  // For discussion of <? extends Object>, see getAllPresent.
  public void invalidateAll(Iterable<? extends Object> keys) {
    for (Object key : keys) {
      invalidate(key);
    }
  }

  @Override
  public void invalidateAll() {
    throw new UnsupportedOperationException();
  }

  @Override
  public CacheStats stats() {

        }
        return Collections.emptyList();
    }

    /**
     * Clears all cached popular word lists.
     */
    public void clearCache() {
        cache.invalidateAll();
    }

    /**
     * Generates a cache key based on the provided parameters.
     *
     * @param seed the seed value
     * @param tags array of tags
     * @param roles array of roles

          @Override
          public void invalidate(Object key) {
            invalidated.add(key);
          }
        };

    List<Integer> toInvalidate = ImmutableList.of(1, 2, 3, 4);
    cache.invalidateAll(toInvalidate);
    assertThat(invalidated).isEqualTo(toInvalidate);
  }

  public void testEmptySimpleStats() {
    StatsCounter counter = new SimpleStatsCounter();
    CacheStats stats = counter.snapshot();

   * Discards any cached values for keys {@code keys}.
   *
   * @since 11.0
   */
  // For discussion of <? extends Object>, see getAllPresent.
  void invalidateAll(Iterable<? extends Object> keys);

  /** Discards all entries in the cache. */
  void invalidateAll();

  /** Returns the approximate number of entries in this cache. */
  long size();

  /**

      Key key = new Key(1);
      String value = key.toString();
      assertThat(cache.getUnchecked(key)).isSameInstanceAs(value);
      assertThat(cache.asMap().isEmpty()).isFalse();
      cache.invalidateAll();
      assertThat(cache.size()).isEqualTo(0);
      assertThat(cache.asMap().isEmpty()).isTrue();
      assertThat(cache.asMap().containsKey(key)).isFalse();
      assertThat(cache.asMap().containsValue(value)).isFalse();