Re: [wsbpel] Proposal to modify getVariableData

[Alex Yiu <alex.yiu@oracle.com>]

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
>
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