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From Arnaud Le Hors <>
Subject Re: The Great Debate: Xml Parsers
Date Wed, 21 Mar 2001 23:08:47 GMT
James M Snell wrote:

> (I'm cross-posting this to the Xerces-dev list so our friends on the
> parser-side of things can follow along and join in)


>    1  Axis must not force the entire message object model to be in memory
> at one time.  In other words, DOM is out.

This is bogus. There is nothing in the DOM that forces one to have the
whole document in memory. The DOM is just an API. A set of interfaces.

> Xerces 1.x ->  Our concern with Xerces 1.x DOM is that it is slow, huge,
> and complicated.  These are the standard complaints with DOM that we've
> all heard (note to the Xerces guys:  I eagerly await the release of
> Xerces2 ! :-) ....)

So far the Xerces2 DOM and Xerces1 DOM are the same. We're
rearchitecturing the parser. We do not have any plan to write a new DOM
implementation (I believe one could very well fit your requirements
though). So, I'm not sure what you're waiting for here but you might be

> JDOM -> Whlie JDOM is smaller and faster than Xerces and DOM,

Unless I miss something and JDOM now includes a parser, comparing JDOM
to Xerces makes no sense.
I assume you mean "while JDOM is smaller and faster than Xerces DOM"
here, right?
I keep hearing that and I'm willing to believe it but I have yet to see
any metrics that shows this is true. And it is certainly not true in all
use cases. For one thing you can traverse a Xerces DOM tree as many
times as you want without creating any new object. JDOM creates a new
iterator on every node you traverse, and every time you traverse it.

So be careful when making such statements. Uless you make them very
specific they generally are wrong.

> which is
> nice, it still does not meet our requirements listed above.  An additional
> issue raised internally at IBM was that JDOM is nowhere near being a
> standard yet.  (As some of you may know, the current Axis codebase uses
> JDOM for it's message processing).  We've all pretty much decided already
> that JDOM should be removed from the core and should be replaced with a
> lightweight XML parser that meets the requirements.

Again, I don't understand what "JDOM [...] should be replaced with a
lightweight XML parser" means. How can you replace a set of classes to
represent an XML document in memory with a parser? Please, rephrase.
Arnaud  Le Hors - IBM Cupertino, XML Strategy Group

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