Re: Uniqueness of QNames in 'extends' attribute

John,

Thx for the comment. I think that we should require uniqueness of 
interfaces at the XML infoset level since it makes no sense to extend from 
an interface twice. Therefore, a duplicate would be a programming error 
and raising it would be helpful to authors who may have forgotten to edit 
a QName after a copy and paste:

"Each QName in the extends attribute information item MUST be unique."

Arthur Ryman,
IBM Software Group, Rational Division

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"John Kaputin (gmail)" <jakaputin@gmail.com> 
05/18/2006 12:39 PM
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Subject
Uniqueness of QNames in 'extends' attribute






When I implemented interface extension in Apache Woden recently I noticed 
that the WSDL 2.0 spec does not say that the QNames in the 'extends' 
attribute of the <interface> element have to be unique, although it seems 
sensible that they should be. Anyway, my implementation just checks for 
duplicate QNames before resolving them to Interface components. 

You may want to add a uniqueness constraint to this section....

2.2.2.2 extends attribute information item
The extends attribute information item lists the interfaces that this 
interface derives from. 
The extends attribute information item has the following Infoset 
properties: 
A [local name] of extends 
A [namespace name] which has no value
The type of the extends attribute information item is a 
whitespace-separated list of xs:QName.

regards,
John Kaputin