public ImmutableMap<C, V> row(R rowKey) {
    checkNotNull(rowKey, "rowKey");
    return MoreObjects.firstNonNull(
        (ImmutableMap<C, V>) rowMap().get(rowKey), ImmutableMap.<C, V>of());
  }

  @Override
  public ImmutableSet<R> rowKeySet() {
    return rowMap().keySet();
  }

  /**
   * {@inheritDoc}
   *

      populateTable(table);
      return table.rowMap();
    }

    void populateTable(Table<String, Integer, Character> table) {
      table.put("foo", 1, 'a');
      table.put("bar", 1, 'b');
      table.put("foo", 3, 'c');
    }

    @Override
    protected Map<String, Map<Integer, Character>> makeEmptyMap() {
      return makeTable().rowMap();
    }
  }

    return ImmutableMap.<C, Map<R, V>>copyOf(columnMap);
  }

  @Override
  public ImmutableMap<R, Map<C, V>> rowMap() {
    // Casts without copying.
    ImmutableMap<R, ImmutableMap<C, V>> rowMap = this.rowMap;
    return ImmutableMap.<R, Map<C, V>>copyOf(rowMap);
  }

  @Override
  @CheckForNull
  public V get(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {

    assertSame(Ordering.natural(), sortedTable.rowMap().comparator());

    sortedTable = TreeBasedTable.create(Collections.reverseOrder(), Ordering.usingToString());
    assertSame(Collections.reverseOrder(), sortedTable.rowMap().comparator());
  }

  public void testRowMapFirstKey() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSame("bar", sortedTable.rowMap().firstKey());
  }

      populateTable(table);
      return table.rowMap();
    }

    void populateTable(Table<String, Integer, Character> table) {
      table.put("foo", 1, 'a');
      table.put("bar", 1, 'b');
      table.put("foo", 3, 'c');
    }

    @Override
    protected Map<String, Map<Integer, Character>> makeEmptyMap() {
      return makeTable().rowMap();
    }
  }

    assertSame(Ordering.natural(), sortedTable.rowMap().comparator());

    sortedTable = TreeBasedTable.create(Collections.reverseOrder(), Ordering.usingToString());
    assertSame(Collections.reverseOrder(), sortedTable.rowMap().comparator());
  }

  public void testRowMapFirstKey() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSame("bar", sortedTable.rowMap().firstKey());
  }

    return ImmutableMap.<C, Map<R, V>>copyOf(columnMap);
  }

  @Override
  public ImmutableMap<R, Map<C, V>> rowMap() {
    // Casts without copying.
    ImmutableMap<R, ImmutableMap<C, V>> rowMap = this.rowMap;
    return ImmutableMap.<R, Map<C, V>>copyOf(rowMap);
  }

  @Override
  @CheckForNull
  public V get(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {

    }

    @Override
    public Map<R, Map<C, V2>> rowMap() {
      Function<Map<C, V1>, Map<C, V2>> rowFunction =
          new Function<Map<C, V1>, Map<C, V2>>() {
            @Override
            public Map<C, V2> apply(Map<C, V1> row) {
              return Maps.transformValues(row, function);
            }
          };
      return Maps.transformValues(fromTable.rowMap(), rowFunction);
    }

    @Override

  }

  @LazyInit @CheckForNull private transient RowMap rowMap;

  @Override
  public Map<R, Map<C, @Nullable V>> rowMap() {
    RowMap map = rowMap;
    return (map == null) ? rowMap = new RowMap() : map;
  }

  @WeakOuter
  private class RowMap extends ArrayMap<R, Map<C, @Nullable V>> {
    private RowMap() {
      super(rowKeyToIndex);
    }

    @Override

   *
   * <p>In contrast, the maps returned by {@code rowMap().get()} have the same behavior as those
   * returned by {@link #row}. Those maps may support {@code setValue()}, {@code put()}, and {@code
   * putAll()}.
   *
   * @return a map view from each row key to a secondary map from column keys to values
   */
  Map<R, Map<C, V>> rowMap();

  /**