All classes that implement ITableModel already have a getRowCount() method. It would be useful to call this method from subclasses of AbstractTableViewComponent, which can access the underlying ITableModel through ITableModelSource.getTableModelSource().getTableModel().
My specific use case is a "PageInfo" component included in a custom Table component that displays something along the lines of "Viewing items x - x of xx." Because any combination of "source" and "columns" parameters to a TableView component results in an AbstractTableModel (which defines getRowCount() as protected), I currently cast getTableModelSource().getTableModel() to an AbstractTableModel and use reflection to call getRowCount(). This works for the range of data sources I currently use with TableView, but is obviously an ugly hack.
Adding getRowCount() to ITableModel would require the following additional changes:
1. Make getRowCount() in AbstractTableModel public.
2. Mage getRowCount() in BasicTableModelWrap public.
3. Make getRowCount() in SqlTableModel public.
I am aware that repeated calls to getRowCount() could create performance issues, especially for database-backed table models such as IBasicTableModel. However, caching the row count can be handled easily in an IBasicTableModel class and is outside the scope of the Table components anyway.
If a change to the ITableModel interface is considered too radical in the near term, a workaround would be to change the access modifier of AbstractTableModel.getRowCount() from protected to public. This would provide easy access to getRowCount in most cases.