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Using Java Xalan extensions with XSLT 

nogeek
Joined:
03/21/2010
Posts:
49

November 03, 2010 20:52:49    Last update: November 23, 2011 08:54:44
My problem is simple: in my XML data, a timestamp is provided as a long integer (number of milliseconds since the "the epoch"). When I do XSLT, I want to display it as a readable string, such as "Mon Nov 01 18:08:48 CDT 2010".

After hours of struggle, I found:
  1. It's not so easy to get the job done with JDK 1.6
  2. There are tons of garbage on the web in this space (suggestions, code snippets that simply don't work)
  3. Simple Xalan extension functions was the only resource that's somewhat informative. Even there some of the examples don't work.


Below is a list of what worked and what didn't.
  1. This works: 
    <xsl:stylesheet version="1.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:java="http://xml.apache.org/xslt/java">

    <xsl:template match="/">
	<xsl:value-of select="java:java.util.Date.new()"/>
    </xsl:template>

</xsl:stylesheet>


  2. This does not (providing long value to Date constructor): 
    <xsl:stylesheet version="1.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:java="http://xml.apache.org/xslt/java">

    <xsl:template match="/">
	<xsl:value-of select="java:java.util.Date.new(1288652928119)"/>
    </xsl:template>

</xsl:stylesheet>

    The transform throws exception: 
    Exception in thread "main" java.lang.VerifyError: (class: time, method: template$dot$0 signature: (Lcom/sun/org/apache/xalan/internal/xsltc/DOM;Lcom/sun/org/apache/xml/internal/dtm/DTMAxisIterator;Lcom/sun/org/apache/xml/internal/serializer
/SerializationHandler;I)V) Expecting to find double on stack
        at java.lang.Class.getDeclaredConstructors0(Native Method)
        at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389)
        at java.lang.Class.getConstructor0(Class.java:2699)
        at java.lang.Class.newInstance0(Class.java:326)
        at java.lang.Class.newInstance(Class.java:308)
        at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.getTransletInstance(TemplatesImpl.java:353)
        at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.newTransformer(TemplatesImpl.java:382)
        at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl.newTransformer(TransformerFactoryImpl.java:618)


  3. This works: 
    <xsl:stylesheet version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:date="xalan://java.util.Date"
  extension-element-prefixes="date">

  <xsl:template match="/" >
    <xsl:value-of select="date:new()"/>
  </xsl:template>
</xsl:stylesheet>


  4. This does not (error is the same as before): 
    <xsl:stylesheet version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:date="xalan://java.util.Date"
  extension-element-prefixes="date">
 
  <xsl:template match="/" >
    <xsl:value-of select="date:new(1288652928119)"/>
  </xsl:template>
</xsl:stylesheet>



None of the above allowed me to set the time. So I created a utility class: 
import java.util.Date;

public class DateUtil {
    public static Date getDate(long time) {
	return new Date(time);
    }
}


  1. This works: 
    <xsl:stylesheet version="1.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:java="http://xml.apache.org/xslt/java">
  
    <xsl:template match="/" >
        <xsl:value-of select="java:DateUtil.getDate(1288652928119)"/>
    </xsl:template>
</xsl:stylesheet>


  2. So does this: 
    <xsl:stylesheet version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:date="xalan://DateUtil"
  extension-element-prefixes="date">
    <xsl:template match="/" >
	<xsl:value-of select="date:getDate(1288652928119)"/>
    </xsl:template>
</xsl:stylesheet>



I think there's a pattern, but nothing makes much sense!
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