Re: [xml-dev] XSTL2.0 stylesheet workarounds for exceptions

From: Jack Bush <>
To: Michael Kay <>
Date: 2009-02-06T13:46:11Z
ID: <>
Thread: Re: [xml-dev] XSTL2.0 stylesheet workarounds for exceptions

Hi Michael,

OK, you are right once again. It was Xalan that was causing a nuisance this time. I have removed Xalan.jar from CLASSPATH and it was smooth sailing with Saxon 9.1 as far as using empty() is concerned. I will use other approaches to associate Saxon 9.1 to this application to gain optimum performance. In the meantime, I now get 2 <hobbie> elements regardless of whether it exist or not. In other word, the default <hobbies>Unknown</hobbies> element is always generated.

The changes made to the original stylesheet are as follows:

<xsl:template match="/">

<xsl:apply-templates select="//ns:p"/>

<xsl:variable name="hobbies" select="ns:p[ns:strong='Hobbies:']"/>

<xsl:apply-templates select="$hobbies"/>

<xsl:if test="empty($hobbies)">

<hobbies>Unknown</hobbies>

</xsl:if>

</employee>

</xsl:template>

<xsl:template match="ns:p[ns:strong='Hobbie:']|ns:p[ns:strong='Hobbies:']">

<xsl:for-each select="ns:a">

</xsl:for-each>

</xsl:template>

As a result, how to change the stylesheet to create a default (<hobbies>Unknown</hobbies>) element only when "ns:p[ns:strong='Hobbies:']" is invalid? Would a <xsl:choose be suitable in this case but I can't seems to wrap it around the second match template.

Thank you very much once again for your invaluable guidances.

Jack

From: Michael Kay <[email protected]>
To: Jack Bush <[email protected]>
Cc: [email protected]
Sent: Friday, 6 February, 2009 8:21:09 PM
Subject: RE: [xml-dev] XSTL stylesheet workarounds for exceptions

System.err.println(hobbiesTransformer.getClass())

to see what XSLT transformation engine you have loaded. All the evidence suggests it's a 1.0 transformer - probably Xalan, possibly Saxon6.

Relying on the classpath to pick up the right XSLT engine is notoriously error-prone. If your code depends on having an XSLT 2.0 processor, the safest thing is to instantiate Saxon directly:

hobbiesTransformer = new net.sf.saxon.TransformerFactoryImpl();

This is incidentally much faster than searching the classpath. (In extreme cases, searching the classpath to find a TransformerFactory can take longer than the entire transformation).

If you don't want a compile-time reference to Saxon in your code, you can either (a) instantiate the factory using reflection, or (b) set the system property

System.setProperty("javax.xml.transform.TransformerFactory", "net.sf.saxon.TransformerFactoryImpl")

Michael Kay

http://www.saxonica.com/

From: Michael Kay <[email protected]>
To: Jack Bush <[email protected]>; [email protected]
Cc: [email protected]
Sent: Thursday, 5 February, 2009 12:26:02 AM
Subject: RE: [xml-dev] XSTL stylesheet workarounds for exceptions

<xsl:template match="ns:p[ns:strong='Hobbie:']|ns:p[ns:strong='Hobbies:']">

Now the only question left is the second half ( ii ) of the original post
included below:



    ( ii ) I also like to add a default generic value for any missing
element. Say if there are no

    <p><strong>Hobbies:</strong></p> in such document, yet I still would
like to generate a

    null element such as <hobbies>Unknown</hobbies>.


You need to do this at the next level up, where you are applying-templates
to the p elements. Something like

<xsl:variable name="hobbies" select="ns:p[ns:strong='Hobbies:']"/>
<xsl:apply-templates select="$hobbies"/>
<xsl:if test="empty($hobbies)">
... default output goes here ...
</xsl:if>

Michael Kay
http://www.saxonica.com/

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