putAll(map);
        }
    }

    @Override
    public String toString() {
        StringBuilder buffer = new StringBuilder("ManagedVersionMap (" + size() + " entries)\n");
        Iterator<String> iter = keySet().iterator();
        while (iter.hasNext()) {
            String key = iter.next();
            buffer.append(key).append('=').append(get(key));
            if (iter.hasNext()) {
                buffer.append('\n');

  }

  @Override
  ImmutableSet<K> createKeySet() {
    return new KeySet<>(this);
  }

  private static final class KeySet<K> extends IndexedImmutableSet<K> {
    private final RegularImmutableMap<K, ?> map;

    KeySet(RegularImmutableMap<K, ?> map) {
      this.map = map;
    }

    @Override
    K get(int index) {

@GwtCompatible
public enum MapFeature implements Feature<Map> {
  /**
   * The map does not throw {@code NullPointerException} on calls such as {@code containsKey(null)},
   * {@code get(null)}, {@code keySet().contains(null)} or {@code remove(null)}.
   */
  ALLOWS_NULL_KEY_QUERIES,
  ALLOWS_NULL_KEYS(ALLOWS_NULL_KEY_QUERIES),
  /**
   * The map does not throw {@code NullPointerException} on calls such as {@code

    assertContainsAllOf(
        keys.entrySet(), Multisets.immutableEntry((K) null, 2), Multisets.immutableEntry(k1(), 1));
  }

  public void testKeysElementSet() {
    assertEquals(multimap().keySet(), multimap().keys().elementSet());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testKeysRemove() {
    int original = multimap().keys().remove(k0(), 1);

              return values().asList().get(index + 1);
            });
    List<Entry<K, V>> orderedEntries = getOrderedElements();
    int index = 0;
    for (K key : getMap().keySet()) {
      assertEquals(orderedEntries.get(index).getKey(), key);
      index++;
    }
  }

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

      return size == keyToIndex().size();
    }

    K getKey(int index) {
      return keyToIndex().keySet().asList().get(index);
    }

    abstract @Nullable V getValue(int keyIndex);

    @Override
    ImmutableSet<K> createKeySet() {
      return isFull() ? keyToIndex().keySet() : super.createKeySet();
    }

    @Override
    public int size() {
      return size;
    }

    return asList(
        getPutNullKeyUnsupportedMethod(),
        getPutAllNullKeyUnsupportedMethod(),
        getCreateWithNullKeyUnsupportedMethod(),
        getCreateWithNullUnsupportedMethod(), // for keySet
        getContainsEntryWithIncomparableKeyMethod(),
        getContainsEntryWithIncomparableValueMethod());
  }

  @Override
  protected Collection<Method> suppressForConcurrentHashMap() {
    /*

  @LazyInit @RetainedWith private transient @Nullable ImmutableSet<K> keySet;

  /**
   * Returns an immutable set of the keys in this map, in the same order that they appear in {@link
   * #entrySet}.
   */
  @Override
  public ImmutableSet<K> keySet() {
    ImmutableSet<K> result = keySet;
    return (result == null) ? keySet = createKeySet() : result;
  }

  /*

  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithKeySetIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<K> iterator = getMap().keySet().iterator();
          getMap().clear();
          iterator.next();
        });
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)

    assertThat(table.rowKeySet()).containsExactly("foo", "bar").inOrder();
  }

  public void testRowOrdering() {
    table = create("foo", 3, 'a', "bar", 1, 'b', "foo", 2, 'c');
    assertThat(table.row("foo").keySet()).containsExactly(2, 3).inOrder();
  }