for (Map<C, V> row : rowMap().values()) {
      if (row.containsValue(value)) {
        return true;
      }
    }
    return false;
  }

  @Override
  public boolean contains(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
    Map<C, V> row = Maps.safeGet(rowMap(), rowKey);
    return row != null && Maps.safeContainsKey(row, columnKey);
  }

  @Override
  @CheckForNull

 * Null row keys, columns keys, and values are not supported.
 *
 * <p>Lookups by row key are often faster than lookups by column key, because the data is stored in
 * a {@code Map<R, Map<C, V>>}. A method call like {@code column(columnKey).get(rowKey)} still runs
 * quickly, since the row key is provided. However, {@code column(columnKey).size()} takes longer,

        rowIterator.remove();
        rowEntry = null;
      }
    }
  }

  @Override
  public Map<C, V> row(R rowKey) {
    return new Row(rowKey);
  }

  class Row extends IteratorBasedAbstractMap<C, V> {
    final R rowKey;

    Row(R rowKey) {
      this.rowKey = checkNotNull(rowKey);
    }

    @CheckForNull Map<C, V> backingRowMap;

    assertSame(original.values(), transpose.values());
    assertEquals(original.row(1), transpose.column(1));
    assertEquals(original.row(2), transpose.column(2));
    assertEquals(original.column("foo"), transpose.row("foo"));
    assertEquals(original.column("bar"), transpose.row("bar"));
  }

  }

  public void testRowMissing() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Map<Integer, Character> row = table.row("dog");
    assertTrue(row.isEmpty());
    try {
      row.put(1, 'd');
      fail();
    } catch (UnsupportedOperationException expected) {
    }
  }

  public void testColumnMissing() {

  }

  public void testRowMissing() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Map<Integer, Character> row = table.row("dog");
    assertTrue(row.isEmpty());
    try {
      row.put(1, 'd');
      fail();
    } catch (UnsupportedOperationException expected) {
    }
  }

  public void testColumnMissing() {

    validateTableCopies(table);
    // Even though rowKeySet, columnKeySet, and cellSet have the same
    // iteration ordering, row has an inconsistent ordering.
    assertThat(table.row('b').keySet()).containsExactly(1, 2).inOrder();
    assertThat(ImmutableTable.copyOf(table).row('b').keySet()).containsExactly(2, 1).inOrder();
  }

  public void testCopyOfSparse() {

   * generated by applying the specified functions. If multiple inputs are mapped to the same row
   * and column pair, they will be combined with the specified merging function in encounter order.
   *
   * <p>The returned {@code Collector} will throw a {@code NullPointerException} at collection time
   * if the row, column, value, or merging functions return null on any input.
   *
   * @since 21.0
   */

    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();
  }

    private final R row;
    private final C column;
    private V value;

    MutableCell(R row, C column, V value) {
      this.row = checkNotNull(row, "row");
      this.column = checkNotNull(column, "column");
      this.value = checkNotNull(value, "value");
    }

    @Override
    public R getRowKey() {
      return row;
    }

    @Override