* documented in the Javadoc. If a row Comparator is provided, cellSet() iterates across the
       * columns in the first row, the columns in the second row, etc. If a column Comparator is
       * provided but a row Comparator isn't, cellSet() iterates across the rows in the first
       * column, the rows in the second column, etc.
       */
      Comparator<Cell<R, C, V>> comparator =

   * 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.
   *

    table.put("one", 'a', 1);
    table.put("two", 'a', 2);
    table.put("three", 'a', 3);
    table.put("four", 'b', 4);
    return Tables.unmodifiableTable(table).column('a');
  }

   * @return the corresponding map from column keys to values
   */
  Map<C, V> row(@ParametricNullness R rowKey);

  /**
   * Returns a view of all mappings that have the given column key. For each row key / column key /
   * value mapping in the table with that column key, the returned map associates the row key with
   * the value. If no mappings in the table have the provided column key, an empty map is returned.
   *

  }

  @Generates
  static <R, C, V> Table<R, C, V> generateTable(R row, C column, V value) {
    return generateHashBasedTable(row, column, value);
  }

  @Generates
  static <R, C, V> HashBasedTable<R, C, V> generateHashBasedTable(R row, C column, V value) {
    HashBasedTable<R, C, V> table = HashBasedTable.create();
    table.put(row, column, value);
    return table;
  }

 *
 * <p>The allowed row and column keys must be supplied when the table is created. The table always
 * contains a mapping for every row key / column pair. The value corresponding to a given row and
 * column is null unless another value is provided.
 *
 * <p>The table's size is constant: the product of the number of supplied row keys and the number of

    return delegate().cellSet();
  }

  @Override
  public void clear() {
    delegate().clear();
  }

  @Override
  public Map<R, V> column(@ParametricNullness C columnKey) {
    return delegate().column(columnKey);
  }

  @Override
  public Set<C> columnKeySet() {
    return delegate().columnKeySet();
  }

  @Override
  public Map<C, Map<R, V>> columnMap() {

    return delegate().cellSet();
  }

  @Override
  public void clear() {
    delegate().clear();
  }

  @Override
  public Map<R, V> column(@ParametricNullness C columnKey) {
    return delegate().column(columnKey);
  }

  @Override
  public Set<C> columnKeySet() {
    return delegate().columnKeySet();
  }

  @Override
  public Map<C, Map<R, V>> columnMap() {

   *
   * <p>The views returned by the {@code Table} methods {@link Table#column}, {@link
   * Table#columnKeySet}, and {@link Table#columnMap} have iterators that don't support {@code
   * remove()}. Otherwise, all optional operations are supported. 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

    assertEquals(ImmutableMap.of("foo", 'a', "bar", 'b'), table.column(1));
  }

  // This test assumes that the implementation does not support null keys.
  public void testColumnNull() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    try {
      table.column(null);
      fail();
    } catch (NullPointerException expected) {
    }
  }