XOM API for Processing XML with Java

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

Hallvard Trætteberg wrote:

> A better (and less constructed) example is an application which had one Text
> node for each line of text, inside some Element (the Text nodes were
> populated from and synchronized with a JList component, the document
> structure was shown in a JTree) When using XPath I really wanted to match
> the individual Text nodes, not the text as a whole. You can argue that this
> doesn't follow the XPath model, but since I controlled the XML document and
> object structure, I wanted this behavior (it was a feature, not a bug).

It seems to me that this case uses Java object boundaries to infer 
structure that is not actually present in the XML document. Therefore 
you want to use XPath to perform queries over this structure not 
expressed in XML.

The principle XOM is going to follow here is that significant structure 
should be marked up with XML, not with extra-XML information such as 
object boundaries. For more of my thoughts on this, see

http://www.cafeconleche.org/books/effectivexml/chapters/11.html

That being said, it is possible use XPath to query non-XML structures. 
For instance, Jaxen 1.1 includes an XPath binding to JavaBeans. You can 
plug other such custom bindings into Jaxen. The Jaxen 1.1 XOM binding 
currently has exactly the behavior you want.

I've just finished writing a binding to Jaxen that gives me the behavior 
I want -- no contiguous text nodes despite adjacent Text objects. I 
suspect this is what I'm going to push out with the next development 
release of XOM 1.1, and which will be the implementation used by the 
query method in Node. However, this shouldn't prohibit alternative 
bindings that implement slightly different models.

FYI, I'm not wedded to Jaxen for the future. I'm seriously considering 
using Saxon 6.5.3+fixes. However, I suspected that I could get a basic 
implementation working with Jaxen a lot faster since the code base seems 
much simpler, and since you had already done a lot of the basic work to 
integrate XOM with Jaxen.

--
Elliotte Rusty Harold  elharo AT metalab.unc.edu
XML in a Nutshell 3rd Edition Just Published!
http://www.cafeconleche.org/books/xian3/
http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim