Take the specified derived group and element short names and determine a
replacement element name to use instead. Most commonly, this is used to strip
the group name if the group is a pseudo-group (DUAL) or the element is a pseudo-group
(ROWNUM). It may also be used to strip special information out of the name in source
value in some specialized cases.
By default, this method returns null, indicating that the normal group and element
name logic should be used (group + "." + element). Subclasses should override and
implement this method if desired.