private int calculateRowSpan() {
int result = 0;
if (children == null) {
result = rowKeys.size();
} else {
for (Iterator itr = children.values().iterator(); itr.hasNext(); ) {
GroupCell gc = (GroupCell) itr.next();
result += gc.getRowSpan();
}
}
result += group.foots.size();
return result;
}
