Re: [ws-caf] Context - XML technical

[Kevin Conner <Kevin.Conner@arjuna.com>]

Hiya Tony.

> I was unaware that a type could be made abstract (in XML) as well as an
> element until I looked up the XML Schema primer the other day to remind
> myself about the use of abstract elements.

This was one of the suggestions I made for the status enumeration :-)

> It appears to me (and I am open to correction) that if we define a context
> element and make its type abstract (rather than making the context element
> abstract), then an instance document will identify the context with the
> context namespace prefix (such as wsctx:context assuming that that prefix is
> declared with an xmlns 'declaration' but will have to include an xsi:type
> attribute that points to the type in the schema where that type is defined
> (need not be the context schema, and will not be if we do not define any
> suitable types in the context schema).  This approach should mean that we
> can define where the context headers go in the WSDL for context services and
> clients but leave open the definition of the precise (extended) structure.
> So change the schema to:
> 
> <xs:complexType name="ContextType" abstract="true">
> 		...
> <xs:element name="context" type="tns:ContextType"/>
> 
> A thought for others to investigate further perhaps.  If it does work maybe
> we should make this change anyway independent of other discussions.

This would certainly allow the identification of context using a consistent element QName but I do not believe it will remove the requirement to understand the type.  I believe it will also alter the soap:mustUnderstand processing, the original reason for the change.

	Kev

-- 
Kevin Conner
Arjuna Technologies Ltd.