How to include a call to JavaScript within XSLT?

Question

I am trying to call JavaScript inside XSLT but it keeps on failing. I am using the Xalan namespace. I'm calling Java as well and that works no problem, but for some reason the JavaScript doesn't.

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:java="http://xml.apache.org/xalan/java" xmlns:xalan="http://xml.apache.org/xalan" xmlns:counter="MyCounter" extension-element-prefixes="counter">
<xsl:template match="/">
    <xalan:component prefix="counter" functions="response">
        <xalan:script lang="javascript">

          function response(name) {
            // Return a string.
            return "" + (name);
          }

        </xalan:script>
     </xalan:component>

    <xsl:value-of select="counter:response('hello')"/> 
    <xsl:variable name="rightNow" select="java:java.util.Date.new()"/><!-- Get date object -->
    <xsl:variable name="formatter" select="java:java.text.SimpleDateFormat.new('MM')"/> <!-- double digit format: append 0 to less than ten -->  
    <xsl:variable name="formattedMonth" select="java:format($formatter, $rightNow)"/> <!-- format it -->
    <p><xsl:value-of select="$formattedMonth"/></p> 
</xsl:template> 
</xsl:stylesheet> 

I get this error in the XML transformer:

<Location of error unknown>java.lang.NoSuchMethodException: For extension function, could not find method java.lang.String.response<ExpressionContext, ]>.

Answer 1

1. Follow Apache's Xalan-Java JavaScript extension instructions , especially being careful to include js.jar and bsf.jar on your classpath. ( Important, but probably not your problem or you would have seen helpful stacktraces. )
2. See also this related SO question . ( Useful, but you've probably already seen. )
3. As @JLRishe mentioned, add functions="response" to xalan:component . ( Proper, but seems not to be strictly necessary, at least in this case. )
4. Move xalan:component out of xsl:template . ( Critical. This is likely the problem here. )

So, running your code thus modified:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:java="http://xml.apache.org/xalan/java"
                xmlns:xalan="http://xml.apache.org/xalan"
                xmlns:counter="MyCounter"
                extension-element-prefixes="counter">

  <xalan:component prefix="counter" functions="response">
    <xalan:script lang="javascript">

      function response(name) {
        // Return a string.
        return "" + (name);
      }

    </xalan:script>
  </xalan:component>

  <xsl:template match="/">
    <xsl:value-of select="counter:response('hello')"/> 
    <xsl:variable name="rightNow" select="java:java.util.Date.new()"/><!-- Get date object -->
    <xsl:variable name="formatter" select="java:java.text.SimpleDateFormat.new('MM')"/> <!-- double digit format: append 0 to less than ten -->  
    <xsl:variable name="formattedMonth" select="java:format($formatter, $rightNow)"/> <!-- format it -->
    <p><xsl:value-of select="$formattedMonth"/></p> 
  </xsl:template> 
</xsl:stylesheet>

Yields the following output as expected:

<?xml version="1.0" encoding="UTF-8"?>hello<p xmlns:xalan="http://xml.apache.org/xalan" xmlns:java="http://xml.apache.org/xalan/java">09</p>