An implementation variant of the TableXYDataset where every series shares the same x-values (required for generating stacked area charts). This implementation uses a DefaultKeyedValues2D Object as backend implementation and is hence more "category oriented" than the DefaultTableXYDataset implementation.

This implementation provides no means to remove data items yet. This is due to the lack of such facility in the DefaultKeyedValues2D class.

This class also implements the IntervalXYDataset interface, but this implementation is provisional.