* collection instance can only be one size at once.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum CollectionSize implements Feature<Collection>, Comparable<CollectionSize> {
  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),

 * collection instance can only be one size at once.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum CollectionSize implements Feature<Collection>, Comparable<CollectionSize> {
  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),

        if (entry.getKey().equals(key)) {
          expectedValues.add(entry.getValue());
        }
      }

      Collection<V> collection = multimap().asMap().get(key);
      if (expectedValues.isEmpty()) {
        assertNull(collection);
      } else {
        assertEqualIgnoringOrder(expectedValues, collection);
      }
    }
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)

      resetContainer();
      Collection<V> collection = multimap().get(key);
      multimap().clear();
      assertEmpty(collection);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testClearPropagatesToAsMapGet() {
    for (K key : sampleKeys()) {
      resetContainer();
      Collection<V> collection = multimap().asMap().get(key);

  }

  @Override
  public boolean containsAll(Collection<?> collection) {
    if (!allowNulls) {
      for (Object object : collection) {
        // behave badly
        if (object == null) {
          throw new NullPointerException();
        }
      }
    }
    return super.containsAll(collection);
  }

  @Override
  public Iterator<E> iterator() {

  public interface CollectionsImplEnum {
    <E extends Comparable<E>> Collection<E> create(Collection<E> contents);

    String name();
  }

  public interface MapsImplEnum {
    <K extends Comparable<K>, V> Map<K, V> create(Map<K, V> contents);

    String name();
  }

  public interface InternerImplEnum {
    <E> Interner<E> create(Collection<E> contents);

    String name();
  }

    }

    @Override
    public boolean addAll(Collection<? extends V> collection) {
      addAll(0, collection);
      return true;
    }

    @CanIgnoreReturnValue
    @Override
    public boolean addAll(int index, Collection<? extends V> elements) {
      checkNotNull(elements);
      checkPositionIndex(index, 0);

    }

    @Override
    public boolean addAll(Collection<? extends V> collection) {
      addAll(0, collection);
      return true;
    }

    @CanIgnoreReturnValue
    @Override
    public boolean addAll(int index, Collection<? extends V> elements) {
      checkNotNull(elements);
      checkPositionIndex(index, 0);

    }

    @Override
    public boolean containsAll(Collection<?> collection) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.containsAll(collection);
    }

    @Override
    public boolean addAll(Collection<? extends E> collection) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.addAll(collection);
    }

    @Override

  public void testAddAll_supportedSomePresent() {
    assertTrue(
        "addAll(somePresent) should return true",
        collection.addAll(MinimalCollection.of(e3(), e0())));
    assertTrue("should contain " + e3(), collection.contains(e3()));
    assertTrue("should contain " + e0(), collection.contains(e0()));
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)