[xsl] XSL cant check if "File exists"?

[Laky Tang <tulaky@xxxxxxxxx>]

I have followed various postings and I am led to
believe that XSL does not have any built in capability
to check if a file exists or not. I read there is a
way to check using extensions, but the following
example gives me an error "Namespace 'java.io.File'
does not contain any functions" in IE and XML spy. It
works incorrectly in Firefox / Flock by always saying
the file does not exist (even if it does). Changing
XSLT 1.0 to 2.0 did not make any difference.
I find it quite ironic that XSLT lacks this basic
capability to check if a file exists-or-not given its
main use is in working with XML documents (and files).
If there is a simple way to gracefully handle the
condition, can somebody please point me in the right
direction? 
Thanks,
-Tulaky
Example adapted from another posting:
------------------------
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
xmlns:fo="http://www.w3.org/1999/XSL/Format";
xmlns:xs="http://www.w3.org/2001/XMLSchema";
xmlns:fn="http://www.w3.org/2005/02/xpath-functions";
xmlns:xdt="http://www.w3.org/2005/02/xpath-datatypes";
xmlns:xlink="http://www.w3.org/1999/xlink";
xmlns:h="http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd";>
<!-- my other templates go here which call this with
the filename-->
<xsl:template name="file_exists"
xmlns:file="java.io.File">
  <xsl:param name="filename" />

  <xsl:if test="not(file:exists($filename))">
  file <xsl:value-of select="$filename"/> does not
exist!
  </xsl:if>
</xsl:template> 
</xsl:stylesheet>



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