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