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RE: LC124

From: <paul.downey@bt.com>
Date: Thu, 7 Jul 2005 21:25:35 +0100
Message-ID: <2B7789AAED12954AAD214AEAC13ACCEF2709E4B7@i2km02-ukbr.domain1.systemhost.net>
To: <umit.yalcinalp@sap.com>, <peter.hendry@capeclear.com>, <www-ws-desc@w3.org>

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]

> 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.

Paul 
Received on Thursday, 7 July 2005 20:25:41 GMT

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