RE: [wsbpel-spec-edit] Issue 94

I am in general agreement that context
sensitive checking doesn’t have to be expressed in schema.  We have a lot
of it.  But I am not a schema Guru so I will leave definitive opinions to you,
Paco and others who feel authoritative on that front :-)

 

 

From: Alex Yiu [mailto:]

Sent: Wednesday, April 07, 2004 1:00 PM

To:


Cc: Alex Yiu

Subject: [wsbpel-spec-edit] Issue
94 

 

Hi all,

I would like to send this proposal for Issue 94 to this editing subgroup first,
before sending it to the main BPEL TC mailing list.

Some background from Issue 95: 

(You can skip this part, if you don't care too much about the usage of schema
validation)

A <rethrow /> activity element is introduced for Issue 95 (Rethrow a
fault). In theory, we can use schema validation to make sure rethrow happens
only within a fault handler. However, since XMLSchema version 1.* is mainly
context free grammar like (as opposed to context sensitive), we may need to
duplicate a lot of XML definition (e.g. "activity" vs
"activityOrRethrow"; "tSequence" and
"tSequenceWithRethrow" and etc), in order to achieve this constraint
in schema validation. This kind of  overhead may be too much for such a
minor syntax differentiation. Therefore, an easier route is taken by just
adding "rethrow" to group "activity" and using implied
semantics of the text of the main spec doc to carry out the post-schema
validation 

Therefore, I suggest to take a similar route for Issue 94

Future version of XML Schema (2.0?) may allow us to add
"co-constraint" to specify this kind of contraints more effectively. 

Proposal to fix issue 94:

(1) Adding compensate to group "activity"

(2) merge tActivityContainer and tActivityOrCompensateContainer

      by replacing all tActivityOrCompensateContainer
with tActivityContainer

        [That means: all tActivityContainer
now allows compensate activity. 

           We should specify
in the text in our spec that compensate activity is allowed only 

            within a
compensation handler]

What do you guys think?

If you guys feel OK about this proposal, I will forward this proposal to the
main BPEL TC mailing list.

Thanks!

Regards,

Alex Yiu