RE: [wsbpel] RE: Issue - 207 - Revised description

["Satish Thatte" <satisht@microsoft.com>]

I agree but can't think of a pithy alternative just now ;-)

In any case we should open an issue.



-----Original Message-----
From: Yaron Y. Goland [mailto:ygoland@bea.com] 
Sent: Monday, June 06, 2005 3:15 PM
To: Satish Thatte
Cc: Furniss, Peter; wsbpel@lists.oasis-open.org
Subject: Re: [wsbpel] RE: Issue - 207 - Revised description

I think of the <compensate/> activity as meaning "call the default 
compensation handler for the enclosing scope" where as I view 
<compensate scope="..."/> as meaning "call the compensation handler for 
the named child scope."

The semantics are indeed different and a name change would seem called
for.

		Yaron

Satish Thatte wrote:
> The use of <compensate/> without a scope name, which Yaron refers to,
perhaps 
> should be named something different because it is different in kind
from the 
> usual scope compensation activity.  The latter is legal only in
enclosing scopes.
> 
>
------------------------------------------------------------------------
--------
> *From:* Yaron Y. Goland [mailto:ygoland@bea.com]
> *Sent:* Thu 5/19/2005 10:54 AM
> *To:* Furniss, Peter
> *Cc:* wsbpel@lists.oasis-open.org
> *Subject:* Re: [wsbpel] RE: Issue - 207 - Revised description
> 
> I'm not sure what you mean. Today it is legal and appropriate to use
the
> compensate activity from inside of a fault handler. I've reviewed this
> mail twice and I'm still not clear as to your concern.
> 
> Could you please give a short example of something that you think is
> illegal in the spec today that this issue would now make legal that is
> causing you concern?
> 
>         Thanks,
> 
>                 Yaron
> 
> 
> Furniss, Peter wrote:
>  > Looking at the substance of this proposed issue, it seems to be
proposing a
>  > rather different model from the existing one.  Surely the existing
model is
>  > that, until a scope exits, anything that it has done but that will
need
>  > unwinding in the event of fault has to be coped with by the fault
handler; after
>  > the scope has exited, it is the responsibility of that scope's
compensation 
> handler.
>  > 
>  > There will be cases where some more sophisticated pattern might
seem more
>  > convenient - if scope B does operation b1, then b2, then b3, all
directly in B,
>  > then the fault handler may need to know if b2 has been done to work
out if it
>  > must undo it. The solution of course is to put the operations each
in its own
>  > scope, in which case B can leave it to the default fault handler to
undo things
>  > backwards, but only of the things that have finished.
>  > 
>  > The issue does raise some questions of what happens if a
compensation handler
>  > itself contains a scope.
>  > 
>  >
>  > Peter
>  >
>  > -----------------------------------
>  > Chief Scientist
>  > Choreology Ltd
>  > 68 Lombard Street, London EC3V 9LJ, UK
>  > web: www.choreology.com
>  > mobile:  +44 7951 536168
>  >
> 
> 
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