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RE: Action Item 2004-07-01 Solution to 168/R114

From: Martin Gudgin <mgudgin@microsoft.com>
Date: Tue, 13 Jul 2004 08:44:10 -0700
Message-ID: <DD35CC66F54D8248B6E04232892B633802B55C76@RED-MSG-43.redmond.corp.microsoft.com>
To: "Sanjiva Weerawarana" <sanjiva@watson.ibm.com>, "WS Description List" <www-ws-desc@w3.org>

 

> -----Original Message-----
> From: www-ws-desc-request@w3.org 
> [mailto:www-ws-desc-request@w3.org] On Behalf Of Sanjiva Weerawarana
> Sent: 13 July 2004 16:22
> To: WS Description List
> Subject: Re: Action Item 2004-07-01 Solution to 168/R114
> 
> 
> Wouldn't this scenario be best solved by defining operation A
> (the one that's gone out to lunch) to be one that returns an
> element whose content model is a choice between Y and Z? That
> is, I don't think this is a good example to motivate leaving
> dispatching out of band.

Actually, I was thinking that maybe operation A defines a message, W,
you have to send before sending X. My point being that there are various
things that are outside the scope of WSDL.

> 
> I'm +1 to leaving dispatching out of band on the basis that
> its the server's business to know how to dispatch and the WSDL
> is what the server has decided to tell *the client*. 

+1

> There's no
> need for the server to tell the client how *it* does its internal
> work.

This is my exact point. I'm sorry the example was so absurd, I'm just
trying to point out exactly what you say above.

> 
> The only case I've seen to justify including that is for "industry
> standard" WSDLs which are intended to be implemented by different
> service providers. That is, the WSDL there does not describe
> a single service offered by someone, but the structure of services
> to be offered  by others. In that case however I imagine the 95%
> scenario will be unique GEDs or some other form that is patently
> obvious to the service implementor.

Absolutely. I expect people to write WSDL this way in many situations. I
just don't want to force people to write WSDL this way.

> 
> My proposal supports both these to work happily. I'm not mandating
> that the SOAPAction based solution be used, but it does provide a
> mechanism to make "dispatching" clear when necessary. 

But the SOAPAction proposal results in a unique action value based on
the operation name apprearing on the wire, yes?

> At the same
> time, we are not precluding other mechanisms (like the one Gudge
> mentioned) from doing what they want.

I'm happy with anything that is OPTIONAL, I'm just not happy mandating
that the service expose internal implementation details...

Sounds like you and I are more or less on the same page.

Gudge

> 
> Sanjiva.
> 
> ----- Original Message ----- 
> From: "Martin Gudgin" <mgudgin@microsoft.com>
> To: "David Booth" <dbooth@w3.org>; "Jeffrey Schlimmer"
> <jeffsch@windows.microsoft.com>
> Cc: "Umit Yalcinalp" <umit.yalcinalp@oracle.com>; "WS 
> Description List"
> <www-ws-desc@w3.org>
> Sent: Tuesday, July 13, 2004 4:00 PM
> Subject: RE: Action Item 2004-07-01 Solution to 168/R114
> 
> 
> >
> >
> > Let's take an interface with operations B and C both of 
> which have the
> > same input message, X. Operation B has an output message Y, while
> > operation C has a different output message Z. Both B and C use the
> > In-Out pattern.  Whether you get message Y or Z back depends on the
> > content of X. Let's for the sake of argument say that if a 
> particular
> > value in X is over 1000 you get Z, otherwise you get Y.
> >
> > I believe that this is a coherent (if somewhat simplistic) 
> example in
> > messaging systems. I also understand that it does not fit 
> particularly
> > well into the RPC style. And that the WSDL does not 
> describe the details
> > of how the server determines whether to send Y or Z. C'est 
> la vie. There
> > is still enough information in the WSDL to construct 
> messages that the
> > service will accept and to deconstruct messages the service 
> will emit,
> > that is to interoperate with the service.
> >
> > Some of you are wondering what happened to operation A. But that's
> > another story...
> >
> > Gudge
> >
> > > -----Original Message-----
> > > From: www-ws-desc-request@w3.org
> > > [mailto:www-ws-desc-request@w3.org] On Behalf Of David Booth
> > > Sent: 08 July 2004 17:40
> > > To: Jeffrey Schlimmer
> > > Cc: Umit Yalcinalp; WS Description List
> > > Subject: RE: Action Item 2004-07-01 Solution to 168/R114
> > >
> > >
> > > At 02:30 PM 7/7/2004 -0700, Jeffrey Schlimmer wrote:
> > >
> > > >WSDL 2.0 should not require identifying the operation name
> > > because doing
> > > >so will unnecessarily limit the applicability of WSDL 2.0.
> > >
> > > Can you give an example?
> > >
> > > >R114 mandates that the WSD language define a way to uniquely
> > > map, but it
> > > >does not mandate that each WSDL document must uniquely map.
> > >
> > > The current wording of R114 is indeed ambiguous ("R114: The
> > > description
> > > language MUST allow unambiguously mapping any on-the-wire
> > > Message to an
> > > Operation.").  It isn't clear whether the "MUST allow" verb
> > > applies to the
> > > _mapping_ or the _writer_of_a_WSDL_document_, i.e., whether
> > > it MUST allow
> > > any message to be mapped to an operation (this would be 
> the stronger
> > > interpretation), or whether it MUST allow a WSDL document to
> > > be written
> > > such that any message can be mapped to an operation (this
> > > would be the
> > > weaker interpretation).  Also, the wording of this
> > > requirement somehow
> > > changed (weakened) after the WG agreed to it on 4 April 2002,
> > > though I
> > > can't find anything in the minutes to justify the change.
> > > (Here is the
> > > chronology that I found:
> > > 
> http://lists.w3.org/Archives/Public/www-archive/2004Jul/0021.html )
> > >
> > > However, I think the precise wording of R114 is somewhat
> > > irrelevant.  The
> > > real question is what does the WG think we need.
> > >
> > > Jeffrey, are you suggesting that you think Scenario X (
> > > 
> http://lists.w3.org/Archives/Public/www-ws-desc/2004Jun/0300.html )
> > > is an acceptable situation and is not a interoperability
> > > problem that we
> > > need to solve?
> > >
> > > >The RPC style (http://www.w3.org/2004/03/wsdl/style/rpc)
> > > defines a way
> > > >to uniquely map and therefore satisfies R114. Nothing 
> else is needed.
> > >
> > > Again, that depends on your interpretation of R114.  
> Unique GEDs also
> > > provide a way to uniquely map.  Personally, I think the weak
> > > interpretation
> > > of R114 would render R114 somewhat pointless, because the
> > > author of a WSD
> > > can always simply write the WSD to use unique GEDs -- nothing
> > > special is
> > > needed in the WSDL 2.0 spec to facilitate this.
> > >
> > >
> > > -- 
> > > David Booth
> > > W3C Fellow / Hewlett-Packard
> > > Telephone: +1.617.253.1273
> > >
> > >
> 
> 
Received on Tuesday, 13 July 2004 11:44:38 GMT

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