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Re: MEPs: Hardcoded or not? (was: Re: Minutes of teleconference02-05-23)

From: Jean-Jacques Moreau <moreau@crf.canon.fr>
Date: Fri, 31 May 2002 18:24:10 +0200
Message-ID: <3CF7A3AA.E25A2C2A@crf.canon.fr>
To: Jacek Kopecky <jacek@systinet.com>
CC: www-ws-desc@w3.org, Glen Daniels <gdaniels@macromedia.com>

Hi Jacek,

Jacek Kopecky wrote:

>  my point was that SOAP MEPs are a different kind of beast from
> WSDL MEPs, like apples and oranges.

Personnally, I eat both!  ;-)

>  In WSDL, MEPs are built from the point of view of one node -
> what messages come and go through it.

I agree.

>  In SOAP, MEPs are built from the point of view of the message
> exchange - what message(s) go through what nodes.

Not exactly. A SOAP MEP is a collection of state machines, one for each node.
The FSM for one node describes the messages that arrive at and leave that
node. So IMO, a SOAP MEP is very related to a WSDL MEP.

> For instance the Simple Request Response can be translated into
> two (not necessarily different) MEPs in WSDL because there are
> two nodes involved.

I don't think so. It's only the FSM of the responding node that matters as
long as WSDL is concerned, i.e. the server, not the client. I see a WSDL MEP
as a potential representation of (part of) a SOAP MEP.

> A generic SOAP MEP will generate one or
> multiple WSDL MEPs (or even multiple usages of one WSDL MEP on
> one node).
>  Let's take a hypothetical Circular Path SOAP MEP where node A
> sends a message to node B, that sends a message to node C and
> that sends a message to node A. In WSDL, this probably maps to
> notification followed by one-way for nodes B and C, and to
> request with an independent response (probably just
> request/response only with different binding information) for
> node A.

I don't think anyone has much experience yet with SOAP MEPs and intermediaries
(your node B certainly looks like a SOAP itermediary to me). I don't know
whether your example would result in one or two WSDL file. I suspect it would
result in two WSDL 1.1 files, but possibly only one WSDL 1.2 (depending on
what we eventually decide on this issue).

> So I still think we have a finite set of MEPs in WSDL and that
> it is limited to (multi)request/(multi)response and one-way.

As I have said above, I believe there is a stronger relationship between a
WSDL MEP and a SOAP MEP than you say.

Received on Friday, 31 May 2002 12:25:36 UTC

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