XSL (Extensible Stylesheet Language)

JDK Tutorials - Herong's Tutorial Examples

∟XSL (Extensible Stylesheet Language) - Implementation in JDK

This section provides a tutorial example on how to write a simple program, XSLClassChecker.java, to view implementation classes of XSL (Extensible Stylesheet Language) in JDK.

JDK offers the following interfaces to support XSL (Extensible Stylesheet Language):

javax.xml.transform.TransformerFactory: The transformer factory class to help to create a transformer object.
javax.xml.transform.Transformer: The abstract class representing a transformer.
javax.xml.transform.Source: The interface representing source objects for the transformer to process.
javax.xml.transform.Result: The interface representing result objects produced by the transformer.

One thing is missing here: who represents the transformation style rules? The answer is that javax.xml.transform.Source also represents transformation style rules, because they written in XML.

I have a simple program here, XSLClassChecker.java, to show what are the XSL implementation classes:

/* XSLClassChecker.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import javax.xml.transform.Source;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.stream.StreamSource;
import javax.xml.transform.stream.StreamResult;
class XSLClassChecker {
   public static void main(String[] args) {
      try {
         TransformerFactory f = TransformerFactory.newInstance();
         System.out.println(f.toString());
         Transformer t = f.newTransformer();
         System.out.println(t.toString());
         Source s = new StreamSource();
         System.out.println(s.toString());
         Result r = new StreamResult();
         System.out.println(r.toString());
         t.transform(s,r);
      } catch (TransformerConfigurationException e) {
         System.out.println(e.toString());
      } catch (TransformerException e) {
         System.out.println(e.toString());
      }
   }
}

Output with JDK 1.8 or higher

herong> java XSLClassChecker.java

com.sun.org.apache.xalan.internal.xsltc.trax
   .TransformerFactoryImpl@1db9742

com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl@25154f

javax.xml.transform.stream.StreamSource@10dea4e

javax.xml.transform.stream.StreamResult@647e05

javax.xml.transform.TransformerException: Result object passed to
   ''{0}'' is invalid.

Note that:

JDK 1.8 is using the com.sun.org.apache.xalan.internal.xsltc.trax package for XSL transformation.
I got the "Result object passed to ''{0}'' is invalid." exception, because the program was transforming from nothing (empty source object) to nowhere (empty result object).

If you are still using JDK 1.4.1, you may get something like:

herong> \j2sdk1.4.1_01\bin\java XSLClassChecker

org.apache.xalan.processor.TransformerFactoryImpl@119298d
org.apache.xalan.transformer.TransformerIdentityImpl@1f33675
javax.xml.transform.stream.StreamSource@1690726
javax.xml.transform.stream.StreamResult@9931f5
javax.xml.transform.TransformerException: No output specified