RE: [ws-tx] Mixed Outcome scenario

["Peter Furniss" <peter@furniss.co.uk>]

Sorry not to get onto this sooner.

On looking at it more closely, I think 1.12 already has the
characteristics we wanted to demonstrate. It doesn't have to be a single
message sent to one PA - the same message sent to multiple Pas has the
same features:

This assumes, in 1.12, that PA1 and PA2 are sent exactly the same
message, including all elements of the context. The Register messages
for PS1 and PS2 will then only differ in fields that are opaque to the
coordinator. Although IA/CS will know there are two participants, it
doesn't know which is considered to be PS1 and which PS2.  Hence the
need for an identification that is carried in the Register and
understood by CS/IA.

With these assumptions, 1.12 is modelling an auction or invitation to
tender scenario. A common message and context is "broadcast" to
potential partners who respond with register and are ready to deliver.
The BA protocol is used to signal who wins. (it doesn't need to be a
single 'winner' of course - maybe everyone who meets some criterion is
accepted) 

(if 1.12 is interpreted as sending different contexts to PA1 and PA2,
then it is really demonstrating nested atomic activities)

The proposal for one PA with two PS's would be the same thing, where the
same party offered more than one response 


Note that although there has to be an identification carried in Register
and understood by CS/IA, it doesn't have to be specified outside this
application. But the ability to carry it DOES have to be supported by
the WS-BA implemenation and made accessible via its (non-standard) API.
(c.f. you steer with a wheel, a tiller or a joystick but you must be
able to steer). 

In this instance, it would work for the Register to carry a field that
had values PS1 or PS2, and there doesn't need to be anything carried in
the application message. That would apply in reality if the difference
between the offered responses could be summarised in a shortish element.

In a more general case, there may be a whole lot of information
travelling in the application response - in which case a (sufficiently)
unique field from the application response is sent on the Register.
Again, the applications on each side need to know what it signifies and
the WS-BA implementations need to be able carry it identifiably and
transparently.

Peter

> -----Original Message-----
> From: Ian Robinson [mailto:ian_robinson@uk.ibm.com] 
> Sent: 31 August 2006 23:45
> To: Peter Furniss; Alastair Green
> Cc: ws-tx@lists.oasis-open.org
> Subject: Re: [ws-tx] Mixed Outcome scenario
> 
> 
> We were unfortunately unable to complete the discussion with 
> Alastair today on the scenario he described in which a single 
> application message resulted in multiple participant 
> registrations. We did agree, within the TC, to add a mixed 
> outcome scenario in which 2 PAs register one participant each 
> - PS1, which will ultimately be closed, and PS2, which will 
> ultimately be compensated. The TC wishes Alastair or Peter to 
> describe in more detail (i.e showing the required message 
> flows in the manner of existing scenarios) a mixed outcome 
> scenario in which the IDENTITY of the registered participant 
> needs to be communicated in some way.
> 
> Once we have such a scenario, we can then discuss whether or 
> not this is something that we believe is in scope for the the 
> MixedOutcome coordinator type and, if it is, whether or not 
> the existing specification actually enables this to be implemented.
> 
> We can schedule discussion of any such detailed scenario on 
> the TC telecon on Sep 21.
> 
> Regards,
> Ian
> 
> 
> 
>                                                               
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>              "Peter Furniss"                                  
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>              <peter@furniss.co                                
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>              .uk>                                             
>           To 
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>              31/08/2006 07:47                                 
>           cc 
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> <peter.furniss@erebor.co.uk>        
>                                                               
>      Subject 
>                                        [ws-tx] Mixed Outcome 
> scenario      
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> 
> Following the discussion yesterday, I'd suggest the following 
> as an outline of a scenario for Mixed Outcome:
> 
> IA sends application request to PA, with Mixed Outcome context
> 
> PA registers two participants "left" and "right" for 
> participant completion, and replies
> 
> PA completes both participants
> 
> IA orders close of "left" and compensation of "right".
> 
> (only have a few minutes now, so elaborate with appropriate 
> terminology etc.  And "left", "right" could be changed (in 
> the scenario specification, not the implementations) to 
> anything else - key thing is the participant's "left" will 
> close, "right" will compensate)
> 
> 
> 
> However, I believe to make that work, we will find we need to 
> reverse the no-change decision on participant identifiers. 
> IA's "view" of the participants must allow it to know which 
> is "left" and which "right". This doesn't require 
> standardisation of "left" and "right" outside the scenario 
> definition. It DOES require that the heterogeneous ws-c+ws-ba 
> implementations can pass a field on at least one message that 
> is put in by PA and received by IA.
> 
> Other variations - including coordinator completion, cancel 
> one, complete other would also be useful.
> 
> 
> 
> 
> You will see this email is sent from a different address. I'm 
> leaving erebor today and joining another company on Monday. 
> I'm not sure whether I'll get messages from the distribution 
> in the meantime, so please cc: peter@furniss.co.uk on 
> replies. (but I'll respond faster on 
> peter.furniss@erebor.co.uk until about 17:00 uk time today)
> 
> 
> Peter
> 
> ------------------------------------
> Peter Furniss
> phone: home   +44 20 8460 8553
>        office +44 20 8313 1833
>        mobile +44 79 51 53 61 68
> email: peter@furniss.co.uk
> web:   www.furniss.co.uk
> 
> 
> 
>