* @since 10.0
 */
@GwtCompatible
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 10.0
 */
@GwtCompatible
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;
    }
  },

   * 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();

  /**

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

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

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

        }
        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

   * 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();
      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));
    }
  }