[jdom-interest] Element comparison

Alex Chaffee guru at edamame.stinky.com
Fri Aug 4 07:17:51 PDT 2000

On Mon, Jul 31, 2000 at 12:52:37PM -0700, Jason Hunter wrote:
> > I need some function to compare the element I created with the 
> > element in the existing document so that I can remove it. 
> Standard thing to do is get the List of content, then remove the
> offending element.  How you determine the "offending element" is your
> decision, and if you want to compare against an existing element in some
> way, then just write that code.  We didn't write .equals() because to do
> a .equals() on an Element is potentially fully recursive down the
> document, and odds are you really just want to compare names and
> namespaces or something.

Yeah, I haven't mentioned it yet, but I think this equals thing is a
flaw. "odds are" is loaded; when I say "element1.equals(element2)" I'm
usually thinking deep compare, though I see the performance problem
with standard Hashtable implementations.

One possible amelioration would be to write a set of Comparators
that can be passed to the java.util sort and compare functions, that

	Shallow/Deep Full Compare
	Shallow/Deep Element-Name-Only Compare With/Without Namespace

or just one comparator with a set of flags for what criteria it uses.

(I haven't come against a situation yet in my short time using JDOM
where I need such a comparator; maybe once I do I'll write it :-)

Alex Chaffee                       mailto:alex at jguru.com
jGuru - Java News and FAQs         http://www.jguru.com/alex/
Creator of Gamelan                 http://www.gamelan.com/
Founder of Purple Technology       http://www.purpletech.com/
Curator of Stinky Art Collective   http://www.stinky.com/

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