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Subject: Re: [ws-caf] Groups - JavaOne 2005 f2f minutes.txt uploaded
Green, Alastair J. wrote: >Two questions > >Do I take it that the defeat of my untabled motion leaves the status quo >ante bellum in place (i.e the result of the whole discussion was "no >change")? > > Which motion was that? >The need to use WS-Context complete for ending of the transaction is >ugly. A "cancelled" signal from any inferior will lead to the ending of >the transaction. > Participants cancelling are reflected only within WS-CF/WS-ACID. Irrespective of how the transaction is instructed to terminate by a "user", that "user" typically won't need to see prior cancellation calls from participants - the fact that the transaction subsequently cancels when the "user" instructs is sufficient. >This is an implied end, unless you force that to be >done at the context level too, which seems increasingly artificial. > > I agree to a point and Greg and I have had a few discussions around this which we were going to present to the group soon. Read below for our current thinking. >How will the outcome be signalled in response to this complete message? >Does context provide for an answer ("completed") to that message? > > Yes. It always has. Here's the current state of affairs: The ability to leverage WS-Context for scoping of activities is important and useful. Currently WS-CF uses the begin/complete to scope the lifecycle of activity groups. WS-ACID (or any of the transaction specifications) acts as Referencing Specification to WS-CF, and hence the leveraging the scoping of activities and activity groups. This means that an activity group and coordinator are created when the activity begins (the wsctx:begin message) and terminated when the activity ends (the wsctx:complete message). Behind the scenes, the Context Service that is tied to a WS-ACID implementation drives the transaction commit or rollback (specified within the extensibility part of the wsctx:complete message). Obviously transaction termination can fail. For example, a request to commit could result in the transaction rolling back if some or all of the participants fail or so vote. As a result, this information needs to flow back in the wsctx:completed message (the one-way "response" to the wsctx:complete message). Currently that capability is not supported, although modifying it is straightforward (and not necessarily something we need to do immediately, if we want to wait for further feedback to the Public Review). Now there is an argument that transaction creation and termination should be handled out of the WS-Context/WS-CF domain. Strictly you could just consider this a termination problem, but for symmetry of the model I think we need to consider both. Without going into implementation details, what this would essentially involve would be a separate service for starting and ending the transaction which is disjoint from the starting and ending of an activity/activity group. This service could be specified within the Referencing Specification, so that it's "operations" are specific to the model it serves. The disadvantage of the above approach is that it now requires multiple "begin" requests if we are supporting transactional activities/activity groups. It allows for totally disjoint activity-to-transaction association and hence breaks the model we've been pushing for WS-Context from the start - that the activity concept is useful across a wide range of use cases and is the way for managing context wherever it is required. Therefore, I think extending wsctx:completed is preferrable because it works within the model. However, our specifications don't preclude the other approach as a vendor specific extension. Mark. >Alastair > >-----Original Message----- >From: mark.little@arjuna.com [mailto:mark.little@arjuna.com] >Sent: 18 July 2005 16:12 >To: ws-caf@lists.oasis-open.org >Subject: [ws-caf] Groups - JavaOne 2005 f2f minutes.txt uploaded > > >The document named JavaOne 2005 f2f minutes.txt has been submitted by Dr >Mark Little to the OASIS Web Services Composite Application Framework >(WS-CAF) TC document repository. > >Document Description: > > >View Document Details: >http://www.oasis-open.org/apps/org/workgroup/ws-caf/document.php?documen >t_id=13659 > >Download Document: >http://www.oasis-open.org/apps/org/workgroup/ws-caf/download.php/13659/J >avaOne%202005%20f2f%20minutes.txt > > >PLEASE NOTE: If the above links do not work for you, your email >application may be breaking the link into two pieces. You may be able >to copy and paste the entire link address into the address field of your >web browser. > >-OASIS Open Administration > > > -- Mark Little Chief Architect Arjuna Technologies Ltd www.arjuna.com
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