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RE: LC124

From: Yalcinalp, Umit <umit.yalcinalp@sap.com>
Date: Thu, 7 Jul 2005 17:19:04 -0700
Message-ID: <2BA6015847F82645A9BB31C7F9D641651BBE9F@uspale20.pal.sap.corp>
To: <paul.downey@bt.com>, <peter.hendry@capeclear.com>, <www-ws-desc@w3.org>

 

> -----Original Message-----
> From: www-ws-desc-request@w3.org 
> [mailto:www-ws-desc-request@w3.org] On Behalf Of paul.downey@bt.com
> Sent: Thursday, Jul 07, 2005 1:26 PM
> To: Yalcinalp, Umit; peter.hendry@capeclear.com; www-ws-desc@w3.org
> Subject: RE: LC124
> 
> 
> Umit
> 
> >As a vendor that considers web services interoperability a major
> > requirement and would like to see versioning problem to be solved
> > interoperably, we have concerns as to positioning the 
> mustIgnores to be
> > the norm as the strong preference of the wg. In our 
> opinion, this is one
> > dimension of versioning and there is no guarantee that the 
> data binding
> > tools may interoperate since their choices are proprietary. 
> Therefore,
> > we share the concerns that Arthur has been bringing up. 
> 
> Interoperability has been our number one concern. Let's face 
> it, interoperability
> is essentially the only reason we use Web services! But, we 
> also have enough
> experience from deploying long lived services used by a 
> number of different
> customers to be aware of the cost of having to manage 
> multiple copies of 
> the same service cloned for just the smallest of changes. 
> That's the status
> quo with Web services today, and one which comes as a surprise to many
> who assume that the reward for using XML, a self describing 
> format, is the
> ability to add additional increments of optional values 
> without breaking 
> existing interactions.
> 
> I'm unclear how the principle of which values should be 
> ignored is likely
> not to be interoperable, given the approach is fairly 
> simplistic and we have 
> the PSVI technique as a reference implementation.
>  
> [snip]

In order to guarantee interop, there needs to be well written and agreed
rules.  AFAIK, the PSVI technique is not really accepted by the
community at large yet. This leaves us with decisions of specific
product teams that affect their implementations. This is why I am very
skeptical although I wish to see this problem solved. 

> 
> > WSDL 2.0 has come a long way. If we want adoption and 
> implementations to
> > be emerging rapidly, incorporating an extended semantics of 
> XML Schema
> > will make vendors to adopt WSDL 2.0 later, not sooner. This 
> is raising a
> > bar which is not really appropriate as the default behavior. 
>  
> That's a fair point, however as discussed, it's possible to 
> easily layer existing 
> schema processors to strip out psvi:notKnown values when 
> validating; binding 
> and mapping tools able to jump over unexpected attributes and 
> elements 
> with little, or in some cases no change. I'd anticipate CR 
> testing to expose 
> issues with implementations.
> 

Sorry, but you can not call this layering easy. It all depends how your
validation was implemented with respect to your databinding. The
feedback that I get internally is that this is not a trivial task for
the existing databinding implementations. Therefore, lets not trivialize
this task. 

I do not really like to talk about LC124 CR testing as if the direction
on LC124 is a done deal. AFAIK I can read the minutes of today's
concall, LC124 is still alive and kicking. 


> Paul 
> 
> 

Cheers, 

--umit
Received on Friday, 8 July 2005 00:18:51 GMT

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