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RE: Use Cases & Requirements

From: Yaron Y. Goland <ygoland@bea.com>
Date: Fri, 23 May 2003 10:02:05 -0700
To: "Assaf Arkin" <arkin@intalio.com>, "Burdett, David" <david.burdett@commerceone.com>
Cc: "WS Chor Public" <public-ws-chor@w3.org>
Message-ID: <GMEOJGJFKALPDCNPFMDOMEBKDCAA.ygoland@bea.com>

The purpose of the cDl is to describe the message choreography. WSDL 1.2's
role is to specify the exact messages and MEPs being used in the
choreography.

So the choreography would say something like: "Foo sends message BLAH to
Bar" where 'message BLAH' would be a reference to a WSDL
service/porttype/operation (or whatever the hell they call it now in WSDL
1.2).

		Yaron

> -----Original Message-----
> From: Assaf Arkin [mailto:arkin@intalio.com]
> Sent: Tuesday, May 20, 2003 11:19 AM
> To: Burdett, David
> Cc: 'Yaron Y. Goland'; WS Chor Public
> Subject: Re: Use Cases & Requirements
>
>
>
> >So, how about this as the layers that are required:
> >
> >1. Template Choroegraphy Definition.
> >   This is written in a CDl and is something that an organization like
> >RosettaNet could develop, but is not specific on detailed message content
> >(as it varies), or the service instances that are used
> >
> >2. (Actual) Choreography Definition.
> >  This is optionally based (by reference) on a Template Choreography
> >Definition but includes the specific message formats, services,
> etc that are
> >used. An open question is whether this is single document or,
> alternatively
> >a Template Choreography Definition with a binding to an instance
> >
> >3. Segmented Choreography Definition
> >  This is a single roles view of a Template (?) Choreography
> Definition and
> >could be used as the starting point for a business process to support the
> >choreography
> >
> >
>  From what I recall RosettaNet has a finite set of patterns (four that I
> can recall) and a lot of different PIPs. Each PIP is defined
> individually because it relates to different set of operations. Each
> operation defines which messages are being used, hopefully generically
> enough to allow some variety. But you won't be plugging an RFQ message
> into a cancel PO PIP, even if the pattern of interaction is the same
> (request/response).
>
> To me this seems to tie well to the recommended use of WSDL for
> abstraction, but I'm beating the same drum over and over ;-)
>
>
> The question I have is what is exactly suggested by the use case. The
> term prose as I read it means a cDl that is not necessarily machine
> processable, just an artifact that you can use to build machine
> processable definitions. In that case you can get as much abstraction as
> you want, either by binding things to it or simply by not specifying
> them. We can imagine a language where you just write templates and
> there's no need for binding. Since a lot of people like to see that,
> that's an option for us to discuss.
>
> But if that's the case, can't we just ignore WSDL? Let other languages
> or standards deal with how to use WSDL for choreographies and let's
> focus on those abstract templates. Use a cDl language not based on WSDL
> to write choreographies, and a language based on WSDL to write actual
> choreography MEPs.
>
> Yaron, if that's what you intended than I need one clarification
> regarding your statement that our deliverables should be based on WSDL
> 1.2. Do you mean that we should identify some non-prose cPl language
> that is based on WSDL and adopt it? Develop both the prose cDl and
> non-prose cPl and the later should use WSDL 1.2? Provide mapping between
> the cDl and some cPl language that does use WSDL and incorporate
> appropriate rules into that mapping?
>
> In short, where does WSDL come into play with respect to the cDl and cPl?
>
> arkin
>
>
>
>
Received on Friday, 23 May 2003 13:04:14 GMT

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