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Re: Defining the meaning of wsdl:required in terms of the document, rather than a processor

From: David Booth <dbooth@w3.org>
Date: Mon, 08 Nov 2004 17:56:06 -0500
To: Roberto Chinnici <Roberto.Chinnici@Sun.COM>
Cc: www-ws-desc@w3.org
Message-Id: <1099954566.3753.26.camel@nc6000.w3.org>

Comments below

On Mon, 2004-11-08 at 13:04, Roberto Chinnici wrote:
> David Booth wrote:
> > Yesterday I accepted an action item:
> > [NEW] ACTION: dbooth to define the meaning of wsdl:required in terms of
> > the document, rather than processor behavior.
> > 
> > I mentioned on the teleconference that I thought we already had wording
> > in the spec to do this, but I wasn't sure.  I've checked, and we do.
> > 
> > Part 1 section 3.1.1 says:
> > [[
> > A mandatory extension is an extension that MAY change the meaning of the
> > element to which it is attached, such that the meaning of that element
> > is no longer governed by this specification. Instead, the meaning of an
> > element containing a mandatory extension is governed by the meaning of
> > that extension. Thus, the definition of the element's meaning is
> > delegated to the specification that defines the extension.
> > ]]
> > 
> > I think that pretty well covers it.  If desired, we might wish to add a
> > note like:
> > [[
> > It therefore follows that if a WSDL processor does not recognize or
> > understand a mandatory extension that it encounters in a WSDL document,
> > the WSDL processor will have no assurance of understanding the meaning
> > of that WSDL document as a whole.
> > ]]
> 
> The statement you quoted earlier was that only the semantics of elements
> in the wsdl namespace that carry mandatory extensions could be modified
> by the extensions themselves. The intent was to allow processors to
> process all other portions of a WSDL document. So saying that "the WSDL
> processor will have no assurance of understanding the meaning of that
> WSDL document as a whole" is a bit misleading, because it seems to imply
> that the entire document is unprocessable.

Yes, I guess I should have phrased it more like:
[[
It therefore follows that if a WSDL processor does not recognize or
understand a mandatory extension that it encounters in a WSDL document,
the WSDL processor will have no assurance of understanding the meaning
of the element to which it is attached.
]]
However, I'm not sure that you'd be able to determine the meaning of a
WSDL document as a whole anyway, if you could not determine the meaning
of one of its elements.

> Also, I'm wondering if something like the following requirement would be
> acceptable:
> 
> [[
> A WSDL processor MUST NOT process the portions of a WSDL document that it
> does not understand due to the presence of one or more mandatory extensions.
> ]]

I don't think that would be adequate, because it sounds perilously close
to saying that if you don't understand it you can safely ignore it --
which certainly is NOT the case for mandatory extensions.

> Since it doesn't mention "faulting", it doesn't seem tied to a particular
> processing model, nor it requires one.
> 
> Roberto
-- 

David Booth
W3C Fellow / Hewlett-Packard
Received on Tuesday, 9 November 2004 03:56:08 GMT

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