RE: Requirements: Decision Points Requirement Proposals

Jon

The idea is that a choreography designer would specify the valid states that
each role in a choreography could have. The idea behind the requirement is
that one participant in a choreography instance could make an inquiry of the
state of another participant in the choreography instance to determine what
their current state was. This could be useful when trying to determine what
action to take after some problem, e.g. a semi-permanent communication
error.

I agree that reliable messaging makes the problem less likely to occur, but
it does not remove the problem. This has already been discussed at length on
thre WS-Architecture WG see the thread starting at [1].

David

[1] http://lists.w3.org/Archives/Public/www-ws-arch/2002Dec/0083.html
-----Original Message-----
From: Jon Dart [mailto:jdart@tibco.com]
Sent: Monday, June 09, 2003 10:27 AM
To: Burdett David
Cc: Yaron Y. Goland; WS Chor Public
Subject: Re: Requirements: Decision Points Requirement Proposals



Burdett, David wrote:

> "The WS Choreography specification MUST provide standardized, reusable
choreography definitions that allow one role to determine another roles
state of processing of a choreography instance, no matter what choreography
definition was being followed."
> 
> "The WS Choreography specification MUST provide standardized, reusable
choreography definitions that allow one role to request another role to
restart the processing of a "stalled" choreography instance, no matter what
choreography definition was being followed." This could simply be a request
to resend some earlier message that got lost.

Forgive me, but if this has been discussed earlier, I missed it, or 
don't recall it.

The first requirement is talking about some kind of introspection 
facility, where a choreography instance can report its own state.

I'm not really clear here how this would work, e.g. are there 
standardized states?

There are also some possible security implications, related to the 
earlier privacy discussion, especially if this query can cross the 
boundaries of a single choreography definition, as suggested.

The second one is less problematic. Although if you are using something 
like a standard reliable messaging protocol, then I presume resend is 
handled at the level of that protocol, not explicitly in the choreography.

--Jon

Received on Monday, 9 June 2003 17:30:40 UTC