>>Hey JAXP,
>>
>>We're interested in adding a schema validation switch on our JAXB compiler that
>>would allow us to reject invalid schemas before trying to process them with our
>>compiler. I was wondering if Xerces 2 had the ability to do this via any of its
>>feature properties
>>(http://apache.org/xml/features/validation/schema-full-checking).
>
>
> There is no feature as such in Xerces2 which can validate a XMLSchema, standalone.
> DOM L3 Abstract Schema spec. at w3c was the one that allowed this thing, but, it
> is no longer being worked upon. But, some of the AS stuff was implemented in xerces
> before w3c made AS a note. Though this is quite a useful thing, I am not sure how
> long the existing AS implementation in xerces is going to live. You can have a look
> at samples/dom/ASBuilder.java which can validate a XMLSchema as a standalone
> entity.
>
> Setting the feature http://apache.org/xml/features/validation/schema-full-checking
> to true asks the parser to do full schema checks e.g. - UPA. This feature is
> relevant only when parser is in schema validation mode.
>
> For the complete list of xerces features and properties, see:
> http://xml.apache.org/xerces2-j/features
> http://xml.apache.org/xerces2-j/properties
>
>
>>Also, Kohsuke suggested looking at the grammar pre-parsing feature of Xerces:
>>
>>
>>>http://xml.apache.org/xerces2-j/faq-grammars.html#faq-3
>>>
>>>I don't know how to turn on full schema checking but I'd expect we can
>>>use the same feature (after all, that's what XML Schema parser XNI
>>>component would recognize.)
>>
>>Can anyone on jaxp-tech give us a pointer in the right direction?
>
>
> Yes, preparsing schemas would be a better option. You can have a look at
> samples/xni/XMLGrammarBuilder.java also. Considering either of the available
> options makes the application more dependent on Xerces as JAXP APIs (for now) do
> not support these.
>

Kohsuke has implemented the JAXB schema validation using the Xerces
grammar preparser feature. However, we would like to restrict our
dependency on Xerces in the future. Tom suggested that we submit an
RFE against JAXP to expose schema validation functionality so we can
rely on the JAXP interfaces instead.

Thanks,

--Ryan
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