XOM API for Processing XML with Java

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

I'm looking at the nu.xom.xslt package and considering a few changes. 
Proposed for your comment:

1. XSLTransform is currently a subclass of XMLException and thus a 
runtime exception. I am reserving XMLException for core exceptions 
(namespace exceptions, well-formedness exceptions,. etc.). 
Furthermore, this exception normally indicates a semantic error in a 
stylesheet that's read in from a source external to the program, so 
this should probably be a checked exception like ParseException 
rather than a runtime exception. Thus this is going to become a 
subclass of Exception rather than XMLException.

2. What should happen when a stylesheet includes <xsl:output 
method="text"/>? The XSLT spec states, "An XSLT processor may output 
the result tree as a sequence of bytes, although it is not required 
to be able to do so (see [17 Conformance]). The xsl:output element 
allows stylesheet authors to specify how they wish the result tree to 
be output." Since the transform method does not output a stream of 
bytes, arguably the xsl:output method simply should not apply here. I 
can override it from inside the API and always produce a list of 
nodes.

What makes this urgent is that JAXP does not specify the behavior 
here, and XOM may be getting different results out of different XSLT 
processors. At least one processor, Xalan, is currently producing 
*no* output when method="text". I think producing a XOM NodeList 
would be a better option here.

Another thing I've considered is producing a list containing only 
text nodes. That's a little trickier, but should be doable.

Same question for method="html". Here the NodeList seems a more 
plausible output.

And for unrecognized custom methods? Should XOM just produce the XML 
tree output as a NodeList, or should it throw an exception?
--

  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