[jdom-interest] JDOM Issue #5 - DTD-aware Attribute output

[Paul Libbrecht]

Rolf,


Le 26 mars 2012 à 17:20, Rolf Lear a écrit :
> Just checking that we have things 'straight'.... since I have not heard
> back from you.

I'm sorry, I'm swamped and have to accept it.

> Three things...
> 1. I said that SAX parser will ignore the DTD unless you 'DTD-validate'...
> but I was wrong, (at least) Xerces SAX parser will apply the default
> attribtues.

And Saxon AElfred.
Xerces is the default in all java distributions of Sun and Apple, or?
(Sun's Xerces that is)

> 2. You said "Removing the validation, sadly disables the passing of
> attribute presence info, it seems." which I think you were saying because I
> had said that before to you.... but this is wrong .. .see above. Do you
> have 'evidence' that this is true though? Or are you basing this on what I
> told you before...?

The example I provided showed it to me: passing no parameter to new SAXBuilder will avoid, with Xerces' default, the passing of any location info.

I'm sorry, I'll have to accept jDOM 2.0 to go out without evaluating a full solution...

paul

> 3. It seems (at least with the Xerces 2.11 parser) that using
> non-validating SAXBuilder will produce the exact results you want... (with
> the exception of Namespace declarations). Can you confirm this?
> 
> I have been thinking about the Namespace problem, and, I don't think that
> there is a 'good' solution on the 'output' side of things, but, there is
> value in having a tool that:
> - scans the entire 'Element' tree
> - 'explicitly' declares namespaces at the highest common node in the tree
> 
> This 'tool' will thus 'declare' the namespace at a 'high' level, and the
> outputter will not need to re-declare them at the lower levels.... which, I
> would guess, would result in removing many low-level Namespace
> declarations, and replace them with a single high-level declaration. This
> would 'solve' your problem in one sense.
> 
> Another alternative for you would be to manually remove the not-specified
> attributes just prior to output:
> 
> 	for (Element e : doc.getDescendants(Filters.element())) {
> 		if (e.hasAttributes()) {
> 			for (Iterator<Attribute> it = e.getAttributes().iterator();
> it.hasNext();) {
> 				Attribute a = it.next();
> 				if (!a.isSpecified()) {
> 					it.remove();
> 				}
> 			}
> 		}
> 	}
> 
> if you physically remove the (default) attributes from the document, then
> they will not affect the namespace calculations for the output either.
> 
> Rolf
> 
> 
>> In fact, going back to the original example, I have the following code:
>> 
>> 	public static void main(String[] args) throws JDOMException,
> IOException {
>> 		String xml = 
>> 
> "http://svn.activemath.org/LeAM-calculus/LeAM_calculus/oqmath/contin.oqmath";
>> 		SAXBuilder builder = new SAXBuilder();
>> 		Document doc = builder.build(xml);
>> 		for (Element e : doc.getDescendants(Filters.element())) {
>> 			if (e.hasAttributes()) {
>> 				for (Attribute a : e.getAttributes()) {
>> 					if (!a.isSpecified()) {
>> 						System.out.println("Attribute was defaulted " + a);
>> 					}
>> 				}
>> 			}
>> 		}
>> 		Format speconly = Format.getPrettyFormat();
>> 		speconly.setSpecifiedAttributesOnly(true);
>> 		XMLOutputter xout = new XMLOutputter(speconly);
>> 		xout.output(doc, System.out);
>> 	}
>> 
>> And it does exactly what you want.... (except for the namespaces).
>> 
>> Rolf
>>