/** Sets the number of rows to span this header.
* <p>It is the same as the rowspan attribute of HTML TD tag.
*/
public void setRowspan(int rowspan) throws WrongValueException {
if (rowspan <= 0)
throw new WrongValueException("Positive only");
if (_rowspan != rowspan) {
_rowspan = rowspan;
smartUpdate("rowspan", _rowspan);
}
}