RE: [wsbpel] Proposal to modify getVariableData

["Ugo Corda" <UCorda@SeeBeyond.com>]

Hi Alex,

Sure, it looks like if your proposal for Issue 103 passes there would be
no need for my proposed change to getVariableData. It would be
necessary, of course, that $var/foo/bar/etc be usable wherever, in xpath
expressions, you can use a node set, but I imagine your proposal implies
that.

So I can either hold on to my proposal until Issue 103 is resolved, or
submit a new Issue and make it dependent on a negative resolution to
Issue 103.

Regards,
Ugo

> -----Original Message-----
> From: Alex Yiu [mailto:alex.yiu@oracle.com] 
> Sent: Friday, May 28, 2004 11:03 AM
> To: Ugo Corda
> Cc: wsbpel@lists.oasis-open.org; Alex Yiu
> Subject: Re: [wsbpel] Proposal to modify getVariableData
> 
> 
> 
> Hi, Ugo,
> 
> Just a reminder ...
> I think the feature you described would be / can be covered 
> by Issue 103 
> also. Issue 103 will remove getVariableData()
> 
> getVariableData('myVar','/foo/bar/etc')
> will become
> $myVar/foo/bar/etc
> 
> And, $var/foo/bar/etc interpretation will be 100% based on 
> standard XPath. That means there will be NO selectionFailure 
> fault attached to it. The 
> xpath selection can return a nodeset of 0, 1, more than 1 node.
>  
> On the other hand, please note that selectionFailure will still hold 
> when the result of expression is passed cross into the 
> <assign> boundary.
> 
> E.g.
> <assign>
>     <from>
>           <expression>$myVar/foo/bar</expression>
>     </from>
>     <to> ... </to>
> </assign>
> 
> if $myVar/foo/bar yields to zero node, the evaluation of that 
> expression 
> does not cause selectionFailure. However, the <assign> part 
> of BPEL will 
> throw selectionFailure fault.
> 
> Make sense to you? :-)
> 
> I am working with some people on TC to finalize the very fine 
> details of 
> mapping WSDL to Schema Element for Issue 103 . Hopefully, the 
> consolidated proposal to vote will be available before the next conf 
> call. :-)
> 
> 
> [Your email further illustrates the importance and elegance of Issue 
> 103. :-) ]
> 
> 
> 
> Regards,
> Alex Yiu
> 
> 
> 
> 
> Ugo Corda wrote:
> 
> >Here is a request I got from my company's BPEL group who is 
> developing 
> >a BPEL implementation for our main product:
> >
> >The getVariableData xpath function should return node sets 
> of any size 
> >(0, 1, >1) instead of throwing a selectionFailure fault in 
> cases where 
> >the resulting node set size is not one.
> >
> >Here are two use cases to explain the request:
> >
> >- If the user is trying to copy a repeating node to another 
> repeating 
> >node they need to know the count of the repeating node so 
> they can use 
> >that count variable in a while loop. Currently getVariableData would 
> >throw a fault and there would be no way to determine the count of a 
> >repeating node and therefore no way to copy repeating nodes.
> >
> >- If the user would like to test for the existence of a node to 
> >determine the route in a business process they would need to have 
> >getVariableData return 0 or 1 node.  Currently getVariableData would 
> >throw a fault and there would be no way to determine if a node is 
> >optional.
> >
> >Thank you,
> >Ugo
> >
> >To unsubscribe from this mailing list (and be removed from 
> the roster 
> >of the OASIS TC), go to 
> >http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/l
eave_workg
>roup.php.
>
>  
>