[gatein-dev] XML Parsing, where do we stand

[Nick Scavelli]

On 02/24/2011 08:13 AM, Julien Viet wrote:
> and by the way the latest code for staxnav can be found here if you 
> want to have a look at it : https://github.com/vietj/staxnav
>
> happy forking

This staxnav version seems to solve the issues I previously had with 
staxnav.  I'll see how this fits with some of the parsing I have done 
already.  Some preliminary testing seems to support most of what I want 
to do, especially the fork method.

- Nick
>
>
> On Feb 24, 2011, at 1:13 PM, Julien Viet wrote:
>
>> First of all, the code written only do XML parsing and not writing 
>> (although for writing I have also some good ideas I put in Chromattic 
>> XML writer (but based on DOM instead of stax), but that is not 
>> something I want to impose at the moment :-) ).
>>
>> Then for judging a framework I would say that the following criteria 
>> matter:
>> - performances (i.e the framework should not degrade much performance 
>> of the wrapped stax implementation)
>> - work with JDK 6 stax implementation (and other implementations as well)
>> - being expressive and have a good ratio of usefull / boiler plate code
>> - pass the "portlet.xml" test (because I think it is the most complex 
>> deployment descriptor we have to handle these days)
>> - wished : it should be part of our codebase to simplify classpath 
>> future classpath problems (given that this will likely part of the 
>> server classpath level).
>>
>> Plain stax should offer the best performances (unless it is misused) 
>> however it is not expressive at all because you need to care about 
>> all stax events (specially the end tag events). The code that would 
>> need to be written for parsing portlet.xml correctly would be hard to 
>> write and maintain (i.e fix bugs).
>>
>> About "staxnav", I don't think it has draw drawbacks, but that is 
>> purely subjective, so I will leave the critic to others.
>>
>> For advantages I consider as valid (maybe I am forgetting some):
>>
>> - it allows to write easy to read and maintain code. For about a week 
>> I spend some time rewriting portlet.xml parsing and it made the code 
>> evolve to address the complexity of portlet.xml parsing.
>> - the codebase remains quite simple and easy to understand
>>
>> Julien
>>
>> On Feb 24, 2011, at 11:54 AM, Thomas Heute wrote:
>>
>>>
>>> Nick, Julien, Alain,
>>>
>>> As said before we'd like to harmonize the XML parsing accross the 
>>> GateIn projects. Let's kill this once for all...
>>>
>>> It doesn't mean we would change the existing parsers overnight but 
>>> it means we will impose a way for any new parsing (or when we decide 
>>> to rewrite a parser).
>>>
>>> If we need parser tools, they will go in Common module ultimately. 
>>> There might be a phase when the code will be duplicated (as Nick's 
>>> tools need to work on an untouched portal where upgrading common is 
>>> not an option).
>>>
>>> We already agreed that StAX as a base was the way to go, I hope we 
>>> still agree ;)
>>>
>>> Let's separate in reading/writing XML (doesn't necessarily 
>>> necessarily mean marhalling/unmarshalling BTW) and agree on both.
>>>
>>> Reading XML:
>>>     Option 1:
>>>         Plain StAX, JBoss AS 7 uses that (in fact they use StAX 
>>> Mapper, a very lightweight library made by the JBoss AS7 team. 
>>> https://github.com/jbossas/staxmapper/ which only helps to work with 
>>> multiple namespaces + some little helpers for ignoring part of the 
>>> file, format the XML when writing...)
>>>         One example of JBoss AS 7 parsing file: 
>>> https://github.com/emuckenhuber/jboss-as/blob/master/web/src/main/java/org/jboss/as/web/WebSubsystemParser.java
>>>     Option 2:
>>>         Nick's stuff (please explain advantages/drawbacks)
>>>     Option 3:
>>>         Julien/Alain's stuff (please explain advantages/drawbacks)
>>>
>>> Writing XML:
>>>     Option 1:
>>>         Plain StAX (well-formed guaranteed over plain Writer)
>>>     Option 2:
>>>         Nick's stuff (please explain advantages/drawbacks)
>>>     Option 3:
>>>         Julien/Alain's stuff (please explain advantages/drawbacks)
>>>
>>> Note that there are other utilities and frameworks based on StAX:
>>>     Stax-Utils: http://stax-utils.dev.java.net/
>>>     StaxMate: http://wiki.fasterxml.com/StaxMateHome
>>>     Apache Axiom: http://ws.apache.org/commons/axiom/
>>>
>>> Thomas/
>>> /
>>
>

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