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From Carsten Ziegeler <cziege...@apache.org>
Subject Re: CForms binding with namespaces error - advice wanted
Date Wed, 23 May 2007 10:00:44 GMT
hepabolu wrote:
> Joerg Heinicke said the following on 22/5/07 22:18:
>> On 22.05.2007 17:07, Helma van der Linden wrote:
>>
>>> // Create the SAX parser and set the features so it creates the 
>>> events we need
>>>                SAXParser parser = 
>>> (SAXParser)manager.lookup(SAXParser.ROLE);
>>>                if( parser instanceof Parameterizable ) {
>>>                    Parameters params = new Parameters();
>>>                    params.setParameter("namespace-prefixes","true");
>>>                    ((Parameterizable)parser).parameterize(params);
>>>                }
>>>
>>> but I'm wondering if that is the correct place to do that.
>>>
>>> OTOH, if it's done at a more global scale, would that have unwanted 
>>> side-effects?
>>
>> I don't know how SAXParsers are set up. But if they are pooled, even 
>> this change has side effects since the SAXParser is returned to the 
>> pool parameterized. Anyway this code smells. No idea how to do it 
>> otherwise though.
> 
> Do you have any idea about what will happen if the parameter setting is 
> added at creation time of the SAXparser? I.e. will it affect 
> performance, memory consumption, behaviour of other parts of Cocoon?
> 
The above code really smells :) It is even not guaranteed to work as 
passing a new set of paramters might not change all of the interal state 
of the component. This might be done in initialize() etc.
In addition if the parser would be thread safe it would change all uses 
of the parser. As noted above, even if the parser is pooled it's causing 
site effects.

So, the only solution is to lookup the parser with the correct 
configuration which means adding another configuration to cocoon.xconf 
and giving it a different role. Then you look up exactly this instance 
and use it.
There is a minimal memory overhead with this solution but that can be 
neglected.

I never liked the sax parser interface (and dom) because of this. It 
would be better if I could pass information like if the parser should 
validate etc. at runtime, e.g. by parse(InputSource, ParserParameters).
We could do this with the new parser interfaces in 2.2...

HTH
Carsten

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