XOM API for Processing XML with Java

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

I've added some API to the XSLTransform class to allow clients to pass 
parameters (values that override xsl:param elements) to XSL engines and 
stylesheets. The API is fairly simple:

public void setParameter(String name, Object value)
public void setParameter(String name, String namespace, Object value)

Passing a null value removes the parameter. There's not currently any 
getParameter method. I can add one if anybody ever needs it, or if 
there's a compelling use case. However, I just prefer not to clutter the 
API until I know there's a need.

I don't think the name is currently checked in any way to see if it's a 
legal NCName. I need to explore what it would mean to pass a non-name as 
a param value. i.e. what would the stylesheet engine do in that case.

The one thing I really agonized over was what the type of the value 
should be. Possibilities include:

1. A String, which most stylesheet engines can convert to numbers; but 
not booleans; at least not in an obvious way. That is, "false" is true.

2. Separate methods for String, boolean, and double; thereby covering 
three of the four XPath types.

3. Object, which avoids method proliferation and allows other types to 
be passed in if needed by extension functions. Also, at least some XPath 
engines will call toString on unexpected types like java.util.Date so 
they can process them as a string.

I'm about 80% convinced that Object is the right type here, but if 
anyone wants to argue otherwise, go ahead. I might still be convinced 
otherwise. I still don't like the idea of passing in an arbitrary object 
that the stylesheet might not be prepared to handle. And of course if 
anybody else spots any other problem with this API that I haven't yet 
seen, holler. These are just my initial thoughts. None of this is 
written in stone yet.

--
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