On Andre's general point:

> Then there's a second issue that I'd very much like to
> understand better - unclear availability of shrink-wrapped
> implementations:
>
> We've done a bit of <desktop research> to find a suitable
> approach, and it appears that neither the WS-* stack of
> specifications (including WS-AT), the OASIS-promoted WS-CAF
> (including WS-TXM) or the older OASIS BTP has gained major
> momentum. Meaning there are few - if any - working real-life
> product implementations that support any of these. I'll be
> glad to be corrected if I'm wrong!
>
> BTW: The new specifications seem to substitute the
> old-fashioned ACID <I> (isolation) with after-the-fact
> compensations, and that appear a bit scary to many people.
> Perhaps this is a contributing reason why even vendors like
> webMethods and SAP have put their decisions and
> implementations on the wait-and-see list?

WS-BA and WS-CAF LRA both use terminology that assumes after-the-fact
compensation (i.e. do it all, then try to go back if not wanted). But
this is an unnecessary self-denying rule - the general case of any
two-round-trip exchange (which all of the protocols in question use)
is to provisionally perform, then EITHER confirm OR cancel. If the
resource/participants are thinking in service-oriented terms, then
it will be their business how they fulfil that contract. One approach
is indeed to do everything in the provisional stage and compensate it
if cancelled. But you could do it the other way round (just check on the

first stage, perform iff confirmed. Or you could take a middle path -
getting to a consciously provisional state which will be changed again
on confirm or on cancel. And what isolation is applied (who from, to
what degree etc, whether system-enforced or application-enforced) is
also a matter for the service, rather than the client.

OASIS BTP is based on this assumption, as is Choreology's Cohesions
(which means the application compenents have to be restrained when
Cohesions is using WS-BA or WS-AT underneath).

(More on this in the Choreology May 2004 feedback to this group,
accessible under "Files" for the group)

Peter

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Choreology Ltd
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