Re: [wsbpel] Issue 27 - Proposal to vote - Setting link status incase of transitioncondition

[Assaf Arkin <arkin@intalio.com>]

Would it be fair to say that the transition condition is always 
evaluated by the enclosing construct?

In other words, if activity X is a source activity and has a transition 
condition, and is encapsulated by activity Y, then activity Y is in fact 
responsible to evaluate the transation condition using the variables 
accessible in its scope and throw a fault if the transition condition 
fails? An enclosing construct may also refuse to evaluate any transition 
conditions (e.g. a while activity or an event handler).

Another point that I don't think was answered so far is what happens 
when there are two transition conditions and a fault occurs when 
evaluating one of them? Are both of them set to false, or only the one 
that generated a fault? I believe for consistency both of the links 
should have their status set to false.

arkin

Satish Thatte wrote:

> You are right, my sentence is misleading.  The link status is false 
> because of the fault not because the transition condition is not yet 
> evaluated.  Thanks for the correction.  Incidentally, the link status 
> matters only if the link target is outside the scope that faulted.
>
>  
>
> ------------------------------------------------------------------------
>
> *From:* Ron Ten-Hove [mailto:Ronald.Ten-Hove@Sun.COM]
> *Sent:* Friday, October 17, 2003 1:22 PM
> *To:* Satish Thatte
> *Cc:* wsbpel@lists.oasis-open.org
> *Subject:* Re: [wsbpel] Issue 27 - Proposal to vote - Setting link 
> status in case of transitioncondition
>
>  
>
> Satish Thatte wrote:
>
> The link status issue is really more general than this as Goran 
> pointed out during the call.  A scope can always fault in an unrelated 
> place while one or more transition conditions within it are being 
> evaluated, in this case, transition conditions on other links sourced 
> at the same source scope.  It is impossible to specify the exact 
> behavior in such races in the presence of true (multi-processor) 
> concurrency.  If the evaluation of the conditions is not complete 
> (i.e., the link has not actually set its status) then the link status 
> is False.  In the case of the fault occurring in the evaluation of the 
> transition condition itself the evaluation of the condition is not 
> complete and therefore the link status is False.
>
> My understanding is that links are tri-state: empty, true, or false. 
> Until the transition condition is evaluated, the link remains marked 
> as empty, not false as you suggested. Faulting the scope should case 
> the link given in this case to marked as false, as part of dead-path 
> elimination.
>
> -Ron
>
>  
>
>  
>
> ------------------------------------------------------------------------
>
> *From:* Prasad Yendluri [mailto:pyendluri@webmethods.com]
> *Sent:* Thursday, October 16, 2003 3:48 PM
> *To:* Ashwini Surpur; Assaf Arkin
> *Cc:* wsbpel@lists.oasis-open.org <mailto:wsbpel@lists.oasis-open.org>
> *Subject:* Re: [wsbpel] Issue 27 - Proposal to vote - Setting link 
> status in case of transitioncondition
>
>  
>
> True. This aspect was clarified in the discussions related to this 
> issue but did not make into the
> proposed resolution (we voted on!).
>
> I also see the need to address what the status of the link ends up 
> being in this scenario. The
> obvious answer seems to that "a transition condition evaluation error 
> would be same as the
> transition condition having evaluated to 'not ture'/false'." But, I 
> somehow feel some will not
> see it this way. In any case we need to make a definitive statement 
> here and not leave a
> loose end dangling.
>
> Regards, Prasad
>
> -------- Original Message --------
>
> *Subject: *
>
> 	
>
> Re: [wsbpel] Issue 27 - Proposal to vote - Setting link status in case 
> of transitioncondition
>
> *Date: *
>
> 	
>
> Thu, 16 Oct 2003 13:18:25 -0700
>
> *From: *
>
> 	
>
> Ashwini Surpur <ashwini.surpur@oracle.com> 
> <mailto:ashwini.surpur@oracle.com>
>
> *Organization: *
>
> 	
>
> Oracle Corporation
>
> *To: *
>
> 	
>
> Assaf Arkin <arkin@intalio.com> <mailto:arkin@intalio.com>
>
> *CC: *
>
> 	
>
> wsbpel@lists.oasis-open.org <mailto:wsbpel@lists.oasis-open.org>
>
>  
>
>Also from the discussion on issue 27 I get that the local variables of the scope 
>
>cannot be used to evaluate the transition condition of the links and only the 
>
>variables of the parent scope should be used. This needs to be documented 
>
>explicitly as well.
>
> 
>
>-Ashwini
>
> 
>
>Assaf Arkin wrote:
>
> 
>
>> Proposal to resolve issue 27 by adding the following paragraph to the
>
>> specification in the description of how links are handled (pages 64/65):
>
>> 
>
>> Note that the transition condition is evaluated after the activity has
>
>> completed. If an error occurs while evaluating the transition condition,
>
>> that error does not affect the completion status of the activity and is
>
>> handled by the activity's enclosing scope. In the case of
>
>> scopes, completion does not necessarily imply successful completion.  A
>
>> scope may suffer an internal fault and yet complete (unsuccessfully) if
>
>> there is a corresponding fault handler associated with the scope and
>
>> that fault handler completes without throwing a fault.
>
>> 
>
>> arkin
>
>> 
>
>> (This is the same proposal sent on Sep 30, resent for your convenience)
>
>  
>
> 
>
>
>
>------------------------------------------------------------------------
>
>
> 
>
>To unsubscribe from this mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup.php.
>
>------------------------------------------------------------------------
>
>To unsubscribe from this mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup.php.
>