[jboss-as7-dev] Validation of XML Parsers / Schemas

[Brian Stansberry]

Subsystem devs, FYI: It is pretty easy to write some parsing tests using 
Kabir's stuff; e.g.

https://github.com/jbossas/jboss-as/blob/master/messaging/src/test/java/org/jboss/as/messaging/test/SubsystemParsingUnitTestCase.java

https://github.com/jbossas/jboss-as/blob/master/jmx/src/test/java/org/jboss/as/jmx/JMXSubsystemTestCase.java


On 9/27/11 2:10 PM, David M. Lloyd wrote:
> I don't think that generic validation in the parser is going to work.
> We've been down this road before.
>
> Ultimately the *best* solution is going to be a code generator for the
> parsers - sort of like JAXB but streaming-friendly instead of mapping to
> object graphs - so that all the validation and parsing logic is factored
> out (the generated implementation will be optimal so that human error
> becomes impossible) and the manually-written code can focus on the logic
> of mapping the XML data to the target model instead of being 80%
> validation like today.
>
> As it is today, you can write element parser methods following a
> definite formula, so this isn't too lofty of a goal in my opinion.  It's
> just a post-7.1 goal, that's all.
>
> On 09/27/2011 02:05 PM, Darran Lofthouse wrote:
>> Yes, at the moment the way I am thinking about this nothing would be
>> *required* to change - the ValidatingXmlReader would just be wrapping
>> the XMLExtendedStreamReader and the underlying calls to the
>> XMLExtendedStreamReader would remain the same so everything can continue
>> using the XMLExtendedStreamReader until ready.
>>
>> I think I would probably actually recommend not pro-actively making a
>> switch but instead for subsystems / domain parsers to switch at the time
>> the schema version is bumped.
>>
>> To begin with if we wanted to to try something out we could even
>> maintain the exact registration / calls we have today and just
>> instantiate the ValidatingXmlReader on the first line of a readElement
>> call to wrap the passed in reader. e.g. As a first step it could be
>> introduced for host.xml reading alone.
>>
>> Regards,
>> Darran Lofthouse.
>>
>>
>>
>> On 09/27/2011 07:38 PM, Brian Stansberry wrote:
>>> Can this be done without *requiring* changes to subsystems?
>>>
>>> ExtensionParsingContext.setSubsystemXmlMapping(String namespaceUri,
>>> XMLElementReader<List<ModelNode>>    reader) is a stable API that we cannot
>>> break.
>>>
>>> A new method could be added to register a parser that requires a
>>> ValidatingXmlReader to be passed in, but we can't force subsystems to
>>> change their impl's
>>>
>>> public void readElement(final XMLExtendedStreamReader reader, final
>>> List<ModelNode>    list) throws XMLStreamException
>>>
>>> to
>>>
>>> public void readElement(final ValidatingXmlReader reader, final
>>> List<ModelNode>    list) throws XMLStreamException
>>>
>>> On 9/27/11 11:42 AM, Darran Lofthouse wrote:
>>>> The topic of how to validate the XML parsers or the schemas crops up
>>>> every now and again.
>>>>
>>>> I have been having a couple of ideas of how we could at some point look
>>>> into this: -
>>>>
>>>> http://community.jboss.org/docs/DOC-17243
>>>>
>>>> The proposed idea actually covers two parts: -
>>>>        - A wrapper around the existing API that allows the parsers to just
>>>> request the elements / attributes they require and leave the wrapper to
>>>> handle all the error handling we currently have distributed across the
>>>> parsers.
>>>>
>>>>       - This then allows us during testing to validate that the calls match
>>>> the structure defined in the schema.
>>>>
>>>> I may try prototyping something other the weekend but thought I would
>>>> put this out there and see if anyone has any thoughts / comments.
>>>>
>>>> Regards,
>>>> Darran Lofthouse.
>>>> _______________________________________________
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>>>> jboss-as7-dev at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/jboss-as7-dev
>>>
>>>
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>
>


-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat