}

  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return delegate().containsColumn(columnKey);
  }

  @Override
  public boolean containsRow(@Nullable Object rowKey) {
    return delegate().containsRow(rowKey);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return delegate().containsValue(value);
  }

  @Override

  }

  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return delegate().containsColumn(columnKey);
  }

  @Override
  public boolean containsRow(@Nullable Object rowKey) {
    return delegate().containsRow(rowKey);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return delegate().containsValue(value);
  }

  @Override

      assertTrue(Thread.holdsLock(mutex));
      return delegate.containsColumn(columnKey);
    }

    @Override
    public boolean containsRow(Object rowKey) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.containsRow(rowKey);
    }

    @Override
    public @Nullable V get(Object rowKey, Object columnKey) {
      assertTrue(Thread.holdsLock(mutex));

      assertTrue(Thread.holdsLock(mutex));
      return delegate.containsColumn(columnKey);
    }

    @Override
    public boolean containsRow(Object rowKey) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.containsRow(rowKey);
    }

    @Override
    public @Nullable V get(Object rowKey, Object columnKey) {
      assertTrue(Thread.holdsLock(mutex));

    public boolean containsKey(@Nullable Object key) {
      return containsRow(key);
    }

    // performing cast only when key is in backing map and has the correct type
    @SuppressWarnings("unchecked")
    @Override
    public @Nullable Map<C, V> get(@Nullable Object key) {
      // requireNonNull is safe because of the containsRow check.
      return containsRow(key) ? row((R) requireNonNull(key)) : null;
    }

    public boolean containsKey(@Nullable Object key) {
      return containsRow(key);
    }

    // performing cast only when key is in backing map and has the correct type
    @SuppressWarnings("unchecked")
    @Override
    public @Nullable Map<C, V> get(@Nullable Object key) {
      // requireNonNull is safe because of the containsRow check.
      return containsRow(key) ? row((R) requireNonNull(key)) : null;
    }

 */
@GwtCompatible
abstract class AbstractTable<
        R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>
    implements Table<R, C, V> {

  @Override
  public boolean containsRow(@Nullable Object rowKey) {
    return Maps.safeContainsKey(rowMap(), rowKey);
  }

  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return Maps.safeContainsKey(columnMap(), columnKey);

 */
@GwtCompatible
abstract class AbstractTable<
        R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>
    implements Table<R, C, V> {

  @Override
  public boolean containsRow(@Nullable Object rowKey) {
    return Maps.safeContainsKey(rowMap(), rowKey);
  }

  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return Maps.safeContainsKey(columnMap(), columnKey);

    /*
     * TODO(jlevy): Support only one of rowKey / columnKey being empty? If we
     * do, when columnKeys is empty but rowKeys isn't, rowKeyList() can contain
     * elements but rowKeySet() will be empty and containsRow() won't
     * acknowledge them.
     */
    rowKeyToIndex = Maps.indexMap(rowList);
    columnKeyToIndex = Maps.indexMap(columnList);

    @SuppressWarnings("unchecked")

    /*
     * TODO(jlevy): Support only one of rowKey / columnKey being empty? If we
     * do, when columnKeys is empty but rowKeys isn't, rowKeyList() can contain
     * elements but rowKeySet() will be empty and containsRow() won't
     * acknowledge them.
     */
    rowKeyToIndex = Maps.indexMap(rowList);
    columnKeyToIndex = Maps.indexMap(columnList);

    @SuppressWarnings("unchecked")