"Type Defintion Cannot be Abstract"

[Lord0]

I am trying to implement variable content containers using an abstract
type and type substitution. My schema is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:this="thi s"
targetNamespace ="this" elementFormDefa ult="qualified" >

<complexType name="abstractA nswerType" abstract="true"/>

<complexType name="yesWithDe scType">
<complexContent >
<extension base="this:abst ractAnswerType" >
<sequence>
<element name="descripti on" type="string" />
</sequence>
<attribute name="answer" type="string" fixed="yes"
use="required"/>
</extension>
</complexContent>
</complexType>

<complexType name="noType">
<complexContent >
<extension base="this:abst ractAnswerType" >
<attribute name="answer" type="string" fixed="no"
use="required"/>
</extension>
</complexContent>
</complexType>

<element name="root">
<complexType>
<sequence>
<element name="question" type="this:abst ractAnswerType" />
</sequence>
</complexType>
</element>

</schema>

When I generate a document using my IDE (oXygen), the following
instance document is created:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns="this"
xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocat ion="this file:/C:/variableContent .xsd">
<question/>
</root>

Which is not valid as "Type Defintion Cannot be Abstract for element
question". I thought my IDE had just failed to perform the type
substition but when I manually create the following instance document:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns="this"
xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocat ion="this file:/C:/variableContent .xsd">
<question answer="yes">
<description>So me text</description>
</question>
</root>

This too is not valid because "Attribute 'answer' is not allowed to
appear in element 'question'." and "Element 'question' must have no
character or element information item [children], because the type's
content type is empty.". So again it appears as if the validator is
failing to realise that "yesWithDescTyp e" is a valid substitution for
"abstractAnswer Type".

I should mention that I can get this to work when I use element
substitution instead of type substitution.

Any thoughts? I feel I am missing something obvious.

Cheers

Lord0

[p.lepin]

On Feb 26, 12:24 pm, "Lord0" <l...@hotmail.c o.ukwrote:

I am trying to implement variable content containers
using an abstract type and type substitution.

[...]

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns="this"
xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocat ion="this file:/C:/variableContent .xsd">
<question answer="yes">
<description>So me text</description>
</question>
</root>

This too is not valid because "Attribute 'answer' is not
allowed to appear in element 'question'." and "Element
'question' must have no character or element information
item [children], because the type's content type is
empty.". So again it appears as if the validator is
failing to realise that "yesWithDescTyp e" is a valid
substitution for "abstractAnswer Type".

I believe XML Schema Part 0: Primer SE, 4.7 explains why
this doesn't work. There doesn't seem to be anything to
help you achieve what you want, though. (I doubt you would
want to use xsi:type, and there doesn't seem to be any
other way to make it work.)

--
Pavel Lepin

[Lord0]

I believe XML Schema Part 0: Primer SE, 4.7 explains why this doesn't work

Thanks for the link - it was very useful.

. There doesn't seem to be anything to
help you achieve what you want, though. (I doubt you would
want to use xsi:type, and there doesn't seem to be any
other way to make it work.)

xsi:type does indeed allow it to work! But you're right - I wouldn't
want to use it.

[Lord0]

Looking at the doc mentioned above there are examples such as

"<complexTy pe name="US-Address" base="ipo:Addre ss"
derivedBy="exte nsion">"

However according to my parser "base" and "derivedBy" are not valid
attributes for element complexType.

Thoughts?