XPath and Namespace mapping

[Tahura Chaudhry <ta...@hotmail.com>]

I am new to Xalan. I have tried out the sample application "SimpleXPathAPI" 
with the command as "SimpleXPathAPI foo.xml /doc name/@last" as instructed 
in the docs. That resulted in the message:  Warning -- No nodes matched the 
location path "/doc".
When I gave the namespace prefix to the above command, i.e. "SimpleXPathAPI 
foo.xml /foo:doc foo:name/@last" it correctly displayed the output "The 
string value of the result is: Marston"

My question is if I didn'tt know ahead of time the prefix but know the 
namespace, then is there a way to construct the XPath expression. Is there a 
class which I can use to map arbitrary prefixes to namespaces and then uses 
those prefixes as path of the XPath expression. If yes, what class is this?

thanks,
Tahura

Re: XPath and Namespace mapping

[da...@us.ibm.com]

> My question is if I didn'tt know ahead of time the
> prefix but know the namespace, then is there a way
> to construct the XPath expression. Is there a class
> which I can use to map arbitrary prefixes to namespaces
> and then uses those prefixes as path of the XPath expression.
> If yes, what class is this?

The prefix is irrelevant -- you can use any prefix in an XPath expression, 
as long as it is bound to the namespace URI of the target node(s) in the 
XML document.  All you need is to derive a class from PrefixResolver that 
knows the prefix and namespace URI mappings for the XPath expressions, and 
use that when you compile the XPath expression you are evaluating.

Dave