Re: [wsrp] xsi:type usage for Extensions

[Subbu Allamaraju <subbu@bea.com>]

Rich Thompson wrote:
> 
> This conformance statement was included for the same reason that the 
> xsi:type attribute was defined. The key is that there is no requirement 
> that there exist a definition of the element in any schema and while the 
> type declaration is redundant in the case such a definition exists, it 
> allows elements with random (undefined) names to be validated because 
> they reference a defined type.

How will this work for an anonymous type (e.g. when an element declares 
the type inline) - there is no named type in this case.

Subbu


> *Subbu Allamaraju <subbu@bea.com>*
> 
> 09/25/2006 01:40 PM
> 
> 	
> To
> 	OASIS WSRP TC <wsrp@lists.oasis-open.org>
> cc
> 	
> Subject
> 	[wsrp] xsi:type usage for Extensions
> 
> 
> 	
> 
> 
> 
> 
> 
> WRRP v1/v2 has a conformance statement that requires all extensions to
> explicitly declare their type using the xsi:type attribute.
> 
> Can someone clarify why this is required? In general, the type
> information can be derived by using the element name and namespace
> information, as in
> 
> <v1:extensions>
>   <ext:foo xmlns:ext="foo:ext:namespace">
>     <ext:bar/>
>   </ext:foo>
> </v1:extension>
> 
> When added, an xsi:type would essentially carry the same information, e.g.
> 
> <v1:extensions>
>   <ext:foo xmlns:ext="foo:ext:namespace" xsi:type="ext:FooType">
>     <ext:bar/>
>   </ext:foo>
> </v1:extension>
> 
> The only time xsi:type is required when the XML is using polymorphism as in
> 
> <v1:extensions>
>   <ext:foo xmlns:ext="foo:ext:namespace" xsi:type="ext:FooSubType">
>     <ext:bar/>
>   </ext:foo>
> </v1:extension>
> 
> where FooSubType is extending FooType. In other cases, xsi:type is not
> required for processing the XML.
> 
> Moreover, the xsi:type attribute cannot be set when the type is
> anonymous (i.e. when the element declares the type inline).
> 
> IMO, this conformance statement is not required. Any comments?
> 
> Regards,
> Subbu
> 
>