W3C home > Mailing lists > Public > public-ws-chor@w3.org > May 2003

Re: Use Cases & Requirements

From: Assaf Arkin <arkin@intalio.com>
Date: Tue, 20 May 2003 11:19:28 -0700
Message-ID: <3ECA71B0.5020106@intalio.com>
To: "Burdett, David" <david.burdett@commerceone.com>
CC: "'Yaron Y. Goland'" <ygoland@bea.com>, WS Chor Public <public-ws-chor@w3.org>

>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
 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 

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?

Received on Tuesday, 20 May 2003 14:22:13 UTC

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