}

  /** @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

@GwtCompatible
@ElementTypesAreNonnullByDefault
public enum RemovalCause {
  /**
   * The entry was manually removed by the user. This can result from the user invoking {@link
   * Cache#invalidate}, {@link Cache#invalidateAll(Iterable)}, {@link Cache#invalidateAll()}, {@link
   * Map#remove}, {@link ConcurrentMap#remove}, or {@link Iterator#remove}.
   */
  EXPLICIT {
    @Override
    boolean wasEvicted() {
      return false;
    }
  },

@GwtCompatible
@ElementTypesAreNonnullByDefault
public enum RemovalCause {
  /**
   * The entry was manually removed by the user. This can result from the user invoking {@link
   * Cache#invalidate}, {@link Cache#invalidateAll(Iterable)}, {@link Cache#invalidateAll()}, {@link
   * Map#remove}, {@link ConcurrentMap#remove}, or {@link Iterator#remove}.
   */
  EXPLICIT {
    @Override
    boolean wasEvicted() {
      return false;
    }
  },

  }

  /** @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() {

    cache.put(2456, 56);
    cache.put(2, 15);

    cache.invalidateAll();
    assertFalse(cache.asMap().containsKey(654));
    assertFalse(cache.asMap().containsKey(2456));
    assertFalse(cache.asMap().containsKey(2));

    cache.put(654, 2675);
    cache.put(2456, 56);
    cache.put(2, 15);
    cache.put(1, 3);

    cache.invalidateAll(ImmutableSet.of(1, 2));

    assertFalse(cache.asMap().containsKey(1));

  }

  /** @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() {

   * 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();

  /**

 * {@code get}; {@link #getAllPresent} is implemented in terms of {@code getIfPresent}; {@link
 * #putAll} is implemented in terms of {@link #put}, {@link #invalidateAll(Iterable)} is implemented
 * in terms of {@link #invalidate}. The method {@link #cleanUp} is a no-op. All other methods throw
 * an {@link UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 11.0
 */

      Key key = new Key(1);
      String value = key.toString();
      assertSame(value, cache.getUnchecked(key));
      assertFalse(cache.asMap().isEmpty());
      cache.invalidateAll();
      assertEquals(0, cache.size());
      assertTrue(cache.asMap().isEmpty());
      assertFalse(cache.asMap().containsKey(key));
      assertFalse(cache.asMap().containsValue(value));
    }
  }

   * 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();

  /**