Re: [wsbpel] Issue - 11 Your opinion requested

[Ron Ten-Hove <Ronald.Ten-Hove@Sun.COM>]

Danny,

    I unfortunately missed your presentation, as I was selfishly 
enjoying my holidays.  However, I've spent some time reviewing the 
materials you provided for the two proposals, and I have to weigh in 
with an opinion of -A -B. In other words, I'm not happy with either 
proposal. Allow me to elaborate.

    Neither solution will be very good at complex transformations; the 
term painful comes to mind. (I suggest that for such transformations we 
should use existing solutions like XSLT, and keep in mind emerging ones, 
like XQuery.)

    A further consideration is that (complex) assignments ought to be 
reuseable. While this is of questionable value for a single BPEL 
process, it is of much greater utility in constructing families of 
processes that share the same available services.

     Finally, both solutions embrace a decidely imperative approach to 
defining the tree structure of a result, when the <assign> activity 
itself can contain the tree structure desired in a declarative fashion 
that is far easier to create and read. Something along the lines of

    <node from=...>          <!-- root node -->
       <node from=.../>      <!-- 1st child of root node -->
       <node from=...>       <!-- 2nd child of root node; or
                                  following sibling to 1st child -->
          <attr from=.../>   <!-- attribute for 2nd child -->
       </node>
    </node>

This uses the XML declaration of the assignment operation to declare the 
structure of the result, rather than depend on DOM-like manipulations to 
describe how to arrive at the result.

    I realise that this is just a list of complaints and partial 
suggestions; this is not a counterproposal. I suspect that not all of us 
share the same notions about what <assign> will be use for. Will it be 
used to construct full-blown XML documents needed for requests (and 
replies), or will it primarily be used to extract document fragments for 
internal bookkeeping purposes?

-Ron