Issue - R33 - Optional XML Data in Assignments

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Issue - R33 - Optional XML Data in Assignments

Status: received
Date added: 9 Nov 2006
Date submitted: 08 November 2006
Submitter: Dieter König
Description: When XML data is defined as optional (minOccurs="0") then
you may run into a selectionFailure when accessing an absent element in
a from-spec. OTOH, it is a likely business scenario to have business
objects with several optional subelements. If multiple of these optional
subelements must be copied individually (the key here is that you
actually access the subelements) you end up with an exponentially
growing number of selectionFailure fault handling combinations for
something that is perfectly valid (i.e. you'd have to model all these).

Another approach to address this situation is the following:

   <if>
      <condition> count($variable/optionalelement) = 1 </condition>
      <assign>
         <copy>
            <from> $variable/optionalelement </from>
            <to> ... </to>
         </copy>
      </assign>
   </if>

The downside of this is that you get a flood of activities AND that you would *not* be able to do multiple <copy>'s in an atomic way anymore (since there'd always be a check for == 1 needed).
Submitter's proposal: Introduce a new attribute suppressFromSelectionFailure="yes|no" on <copy> (the default is "no"). If set to "yes" then the <copy> would be a *no-op* instead of throwing selectionFailure when the from-spec returns zero nodes. Note that the selectionFailure would still be thrown when you try to access an nonexistent element in the *to*-spec.

Optionally - to be discussed as well - apply the following variations:

1. add the new attribute also to higher-level elements (<assign>, <scope>, <process>) in order to let multiple <copy> elements inherit its value.
2. add the new attribute to <from> instead of <copy> and let it also apply also variable initializations.

Changes: 9 Nov 2006 - new issue

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