return null;
}
BoundarySpec s = wfSpec.getStart();
BoundarySpec e = wfSpec.getEnd();
WindowFrameDef wfDef = new WindowFrameDef(wfSpec);
wfDef.setStart(translateBoundary(qDef, s, iInfo));
wfDef.setEnd(translateBoundary(qDef, e, iInfo));
int cmp = s.compareTo(e);
if ( cmp > 0 )
{
throw new WindowingException(sprintf("Window range invalid, start boundary is greater than end boundary: %s", wfSpec));