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Re: More illumination? ( was RE: Contradictions regarding transitivity of wsdl:import)

From: David Booth <dbooth@w3.org>
Date: Sat, 16 Apr 2005 12:02:44 -0400
To: Martin Gudgin <mgudgin@microsoft.com>
Cc: Arthur Ryman <ryman@ca.ibm.com>, www-ws-desc@w3.org
Message-Id: <1113667364.13968.514.camel@nc6000.w3.org>

That's a pretty good illustration of how the non-transitive nature of
"import" is supposed to be enforced.  But I think it also illustrates my
point: the assumption that "if it is in the component model, then it can
be referenced" is a very natural assumption for a spec reader to make. 
(You employed this assumption in your illustration.)  This is why I
think it would be clearer for the component model to adopt this approach
instead of the current approach, in which components can exist in the
component model without actually being visible to (or referenceable
from) certain other components, depending on whether there was an import
statement at the XML Infoset level.

On Fri, 2005-04-15 at 20:50, Martin Gudgin wrote:
> OK, let's step back a bit...
> For the same of illustration, lets say that somehow, let's not worry
> about exactly how, I construct a component model per the current WSDL
> spec *without* using WSDL documents. And let's say that the resulting
> component model contains components from namespaces A, B and C. It is
> clear to me that any component in any of those namespaces can refer to
> any other component in any one of those namespaces. 

> So a binding
> component in namespace A could refer to an interface component in
> namespace A, B or C.
> Now, we have a rule, just like XML Schema, that at the WSDL document
> level, in order to legally refer to components in another namespace a
> WSDL document MUST contain a wsdl:import statement for that namespace.
> Such a statement is a necessary condition to refer to components in
> another namespace *at the document level*. So it's a serialization
> detail, but an important one, because it tells a WSDL parser what other
> namespaces it's going to need in order to resolve references in the
> document its parsing.
> So, when I come to serialize my 'synthetic' component model, as I write
> out the WSDL document for namespace A, I look to see what other
> components in other namespaces are referred to by the components in
> namespace A. If only components from B are referenced, then as I write
> out a.wsdl, I only need a wsdl:import for B. Same for components in
> namespace B. If they only refer to components in namespace C, then as I
> write out b.wsdl, I only need a wsdl:import for C.
> If components in A refer to components in B and C, then when I write out
> a.wsdl, I need two wsdl:imports one for B and another for C.
> Does that help?
> Gudge

David Booth
W3C Fellow / Hewlett-Packard
Received on Saturday, 16 April 2005 16:02:47 UTC

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