XOM API for Processing XML with Java

[Elliotte Rusty Harold <elharo AT metalab.unc.edu>]

At 1:27 PM -0400 9/19/03, John Cowan wrote:


> >  A program that does
> >  the wrong thing 1000 times faster is useless.
>
> Which would you rather have, a version of Saxon with one bug less, or one
> that ran 1000 times faster?

Well, let's see. How much time would I save if Saxon, already quite 
fast, ran 1000 times faster? It might save me a minute or two on my 
most demanding transforms, a few times a year. That would be useful. 
Of course that is time I can multitask on other things like reading 
e-mail, so it's not time that's purely wasted.

On the other hand, if Saxon had had one less bug (and the right one 
less bug) a month or two ago, it would have saved me hours of time I 
spent tracking down a Saxon problem, and would have allowed me to 
continue using Saxon in XOM rather than Xalan. I think I'd rather 
have one less bug. :-)

> >  Parsing currently short circuits a lot of checks the parser has
> >  already done. I should be able to short this one too, though it may
> >  not currently be short circuited in 1.0d21.
>
> If you make the test I mentioned above (which someone else on the list came
> up with, not me), then it is implicitly in effect during parsing, 
> since parsers
> always add new nodes to old.

I thought of that, and it may be true. However, I need to look at it 
more closely. Although that's how the parser behaves, I think XOM 
currently builds up subtrees completely before attaching them to the 
parent node. That is, an element node is only attached to its parent 
on the endElement(), not startElement(). This is useful for filtering 
and streaming. However, it does mean that non-empty elements have 
children when added to their parent.

However, this is probably temporary. I should be able to special case 
the parser's adding of nodes to short circuit this and a couple of 
other minor tests.


--

  Elliotte Rusty Harold
  elharo AT metalab.unc.edu
  Processing XML with Java (Addison-Wesley, 2002)
  http://www.cafeconleche.org/books/xmljava
  http://www.amazon.com/exec/obidos/ISBN%3D0201771861/cafeaulaitA