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

From: Jacek Kopecky <jacek@systinet.com>
Date: Fri, 31 May 2002 12:38:38 +0200 (CEST)
To: Jean-Jacques Moreau <moreau@crf.canon.fr>
cc: www-ws-desc@w3.org, Glen Daniels <gdaniels@macromedia.com>
Message-ID: <Pine.LNX.4.44.0205311222460.26007-100000@mail.idoox.com>

 Jean-Jacques, 
 my point was that SOAP MEPs are a different kind of beast from 
WSDL MEPs, like apples and oranges.
 In WSDL, MEPs are built from the point of view of one node -
what messages come and go through it.
 In SOAP, MEPs are built from the point of view of the message 
exchange - what message(s) go through what nodes.
 For instance the Simple Request Response can be translated into
two (not necessarily different) MEPs in WSDL because there are
two nodes involved. 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.
 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.
 Best regards,

                   Jacek Kopecky

                   Senior Architect, Systinet Corporation
                   http://www.systinet.com/



On Thu, 30 May 2002, Jean-Jacques Moreau wrote:

 > 
 > So far, the only two SOAP MEPs we have (well, one and a half, really)
 > are between two nodes only. IMO, we should be able to model such simple
 > MEPs in WSDL.
 > 
 > Jean-Jacques.
 > 
 > Jacek Kopecky wrote:
 > 
 > >  Jean-Jacques,
 > >  IMO in WSDL the term MEP is a bit different from SOAP MEP. The
 > > difference is that in SOAP an MEP may span multiple nodes and is
 > > defined from the point of view of a message, whereas WSDL
 > > describes one node and all MEPs used in WSDL must be defined from
 > > the point of view of that one described node.
 > >  In WSDL, other MEPs than one-way and request/response should
 > > IMHO be viewed as orchestration, out of scope of WSDL. Therefore
 > > we can hardcode these two.
 > >  Best regards,
 > >
 > >                    Jacek Kopecky
 > >
 > >                    Senior Architect, Systinet Corporation
 > >                    http://www.systinet.com/
 > >
 > > On Fri, 24 May 2002, Jean-Jacques Moreau wrote:
 > >
 > >  > I was not able to attend yesterday, and I apologize in advance if
 > >  > I am reiterating a discussion that has occured already, but I
 > >  > wanted to point out that I agree with Glen and that, if possible,
 > >  > MEPs should not be hardcoded into the spec.
 > >  >
 > >  > Specifically, SOAP 1.2 currently defines one MEP. It is expected
 > >  > that specification for other MEPs will be produced in the future.
 > >  > I think it would be desirable that these other MEPs can be
 > >  > described in WSDL, otherwise there will be services out there
 > >  > that cannot be described (and hence used).  It would be desirable
 > >  > if these other MEPs can be described without us reopening the
 > >  > whole spec every time.
 > >  >
 > >  > Thank you,
 > >  >
 > >  > Jean-Jacques.
 > >  >
 > 
Received on Friday, 31 May 2002 06:39:26 GMT

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