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Extension of Simple Types

From: Michael Zoratti <m.zoratti@nortelnetworks.com>
Date: Thu, 5 Apr 2001 12:03:00 -0400
Message-ID: <CEDFCAE711ADD4118B030008C7E674A41CA51A@nbrwd469.ca.nortel.com>
To: "'www-xml-schema-comments@w3.org'" <www-xml-schema-comments@w3.org>

 My Name is Mike Zoratti, I am a Software Architect with Nortel. Over the
last year
we have been working on a Sun JCP to come up with standard interfaces for
OSS products.  The link below describes the initiative.


The interfaces defined use standard EJB interfaces, but as well define XML
based interfaces.
Actually Nortel is a big supporter of XML based interfaces. I actually
worked on deriving
the XML interfaces based on the EJB interfaces. The mapping is almost always
1-1, the W3C did a very good job on the Schema Definition Language. One
where the mapping is not 1-1 is in the use of Enumerations (i.e. Simple

The definition of a simpleType that defines a set of enumerations is as

<simpleType name="OrderState">
	<restriction base="string">
		<enumeration value="open"/>
		<enumeration value="open.not_running"/>

We have a base schema that defines these enumeration types and obviously
element type-definitions
that are based on the enumeration types. The base schema can however be
derived (imported into a 
derived schema) and in some instances the base enumeration types may need to
be extended, the same
way complexTypes can be extended.  The problem is that I have not found
of extending a simpleType enumerations. The way enumerations are defined,
based on restriction,
I don't know if you would even want to change the language to allow
extension. There may be a way
of extending simpleTypes and if so I would appreciate you passing that
knowledge on to me. 

If there is not a way of extending enumerations, please read-on.

Since we are on a deadline to define the interfaces, I came up with a
recommendation in
dealing with extending enumerations. The below document contains the
enumeration section of a
XML Design Guideline we came up with. It is basically a work around and not
exactly a clean solution.
I would appreciate any comments, whether our guildeline is a recommended
practice in dealing with 
extension of simpleTypes.

I would greatly appreciate your comments

Mike Zoratti
Software Architect
Nortel Networks
Toronto, Ont
(416) 672-2727 X 4817

 <<XMLDesignGuildelinessubset.doc>>  <<XMLDesignGuildelinessubset.txt>> 

Received on Thursday, 5 April 2001 12:04:04 UTC

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