Xpath runtime evaluation?

Question

Hi all,
We would like to give our Dataspace consumers the ability to push some XPath down to the DataServices themselves. We are aware of how can this be done using the mediator API. We are in doubt whether this can be done via WebServices, using an extra param for the XPath expression. Something along the lines of
declare function tns:getWithXPath($id as xs:string, $xpath as xs:string) as element(ns2:TypeofElement)*{
for $elem in tns:getAll()
where $id eq $elem/Id
return
bea:xpath-eval($elem, $xpath)
[I hear there are implementations|http://lists.xml.org/archives/xml-dev/200710/msg00065.html] that manage to do that, in spite the fact that having such a function would introduce ambiguity in the return type.
Can it be done in ODSI?
Thanks in advance
(Also as SR:7667695.992)
Edited by: vlf on Jul 2, 2009 4:36 AM

Answer 1

We are aware of how can this be done using the mediator API. The webservice api is almost exactly identical to the java (mediator) API. What is it you can do in the java api that you cannot do in the java api?
Your requirement sounds like a case for using ad hoc queries. Off the top of my head, I don't recall if that is exposed via webservices - I don't think it is. Check the Advance API Examples that are references in an Announcement in this forum.