Calling Java method with Variable Argument in XSLT

Question

I have a Java method with variable argument which I need to call from XSLT (1.0). But it doesn't work, it keeps failing with the following error:

javax.xml.transform.TransformerConfigurationException: Could not compile stylesheet

However, if I expand the variable argument, it works!

Example:

 public static String getValue(String key, String... args) {  // this is what I want, but doesn't work

 public static String getValue(String key, String args1) { // this works

 public static String getValue(String key, String args1, String args2) { // this works

In XSLT:

<xsl:value-of select="myjavaclass:getValue('MyKey','Arg1')"/>

<xsl:value-of select="myjavaclass:getValue('MyKey','Arg1','Arg2')"/>

So, does anyone know if I can use Java method with variable argument in XSLT? I hope I don't have to create different methods for each number of argument.

Thank you much!

Answer 1

As far as reflection is concerned a varargs method like

public static String getValue(String key, String... args)

is a method with two parameters, the first is a String and the second is a String[]. When you call a varargs method from Java code the compiler generates bytecode to bundle up the variable args into an array, but when you're calling by reflection, as will be the case here, you have to build the array yourself.

So the question becomes, does your XSLT processor provide any way to pass parameters of type String[] from XSLT to Java? In the case of Xalan (the default javax.xml.transform implementation if you don't have another one on your classpath) I believe the answer is no, except in the special situation where the String[] was returned by another extension function.

Answer 2

Since your first argument is also of type String, I think its causing the issue.

Try

     public static String getValue(String... args) {
           String key = args[0];
           String arg1 = args[1];
           .....  
     }