XPath extension functions

[Gregor Karlinger <gr...@iaik.at>]

Hi all!

I am using only the XPath processing parts of Xalan/Java, i. e. 
no XSLT related functionality.

I have to add an additional function to the set of available
function for processing an XPath expression. The function can be
described as follows:

name: here

input parameter: none

output parameter: a XPath node set containing either an attribute
                  or a processing instruction node

I have glanced some documentation files and the API documentation,
and I guess I have to extend the function 

  org.apache.xalan.xpath.Function

The open questions from my point of view are:

* Which of the two "execute" methods do I have to overwrite?

* What do the arguments of these "execute" methods mean?

* What is the linking between the name of my Xpath function
  and its implementing class, i. e. how can I tell Xalan where
  it can find the associated function implementation for a
  XPath function?

Can anybody provide some hints how I can work this out?

Thanks, Gregor
---------------------------------------------------------------
Gregor Karlinger
mailto://gregor.karlinger@iaik.at
http://www.iaik.at
Phone +43 316 873 5541
Institute for Applied Information Processing and Communications
Austria
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