XSL Transformation With Xalan - Meeting The World's Greatest Detective
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With everything installed and configured, it's time to get your hands dirty. First up, a simple example, just to get you comfortable with how Xalan works. Consider the following XML file, snipped out from my XML-encoded address book:

<?xml version="1.0"?>
<me>
   <name>Sherlock Holmes</name>
   <title> 
World's Greatest Detective</title>
   <address>221B Baker Street, London, 
England</address>
   <tel>123 6789</tel>
   <email>sherlock@holmes.domain.com</email>
 
  <url>http://www.method_and_madness.com/</url>
</me>

Now, let's suppose I wanted to convert this snippet into the following plaintext file:

Contact information for "Sherlock Holmes, World's Greatest Detective"
Mailing 
address: 221B Baker Street, London, England
Phone: 123 6789
Email address: sherlock@holmes.domain.com
Web 
site URL:  http://www.method_and_madness.com/

Here's the XSLT stylesheet to get from point A to point B:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output 
method="text" />   
<xsl:template match="/" >
Contact information for "<xsl:value-of 
select="normalize-space(me/name),
<xsl:value-of select="normalize-space(me/title)" 
/>" Mailing address:
<xsl:value-of select="normalize-space(me/address)" />
Phone: 
<xsl:value-of select="normalize-space(me/tel)" />
Email address: <xsl:value-of 
select="normalize-space(me/email)" /> Web
site URL: <xsl:value-of select="normalize-space(me/url)" 
/>
</xsl:template> </xsl:stylesheet>

Now, we've got the XML and the XSLT. All we need is something to marry the two together.

// import required classes
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
import 
java.io.*;

public class addressBookConverter {

   // store the names of the 
files
   public static String xmlFile, xslFile, resultFile = "";
   
   // constructor
 
  public addressBookConverter(String xmlFile, String xslFile, String
resultFile) 
{
      try {

         // create an instance of the TransformerFactory
     
 
   // this allows the developer to use an API that is independent
of 
      
  
 // a particular XML processor implementation. 
         TransformerFactory 
tFactory 
= TransformerFactory.newInstance();
         
         // create a transformer 
which takes the name of the stylesheet
         // as an input parameter. 
  
 
      // this creates a Templates object which is applied to the XML
file 
 
  
      // in the next step
         Transformer transformer = tFactory.newTransformer(new
StreamSource(xslFile));
 
        
         // transform the given XML file with the Templates object 
 
        transformer.transform(new StreamSource(xmlFile), new
StreamResult(resultFile));

 
        System.out.println("Done!");
        } catch (TransformerException e) 
{   
         System.err.println("The following error occured: " + e);
      
 
 }   
   }
  
   // everything starts here
   public static void main (String[] 
args) {
      if(args.length != 3) {
               System.err.println("Please 
specify three parameters:n1.
The name and path to the XML file.n2. The name and 
path to the XSL
file.n3. The name of the output file.");
              return;
 
      }      
      
      // assign the parameters passed as input parameters 
to 
      // the variables defined above
      xmlFile = args[0];
      xslFile 
= args[1];
      resultFile = args[2];
   
      addressBookConverter myFirstExample 
= new addressBookConverter
(xmlFile, xslFile, resultFile);
    }

}

Now compile the class:

$ javac addressBookConverter.java
{/output]

Assuming that all goes well, you 
should now have a class file named
"addressBookConverter.class". Copy this class 
file to your Java
CLASSPATH, and then execute it. 

[output]
$ java addressBookConverter

Ummm...Houston, we have a problem. Here's what you should see (unless you're really intelligent and spotted me setting you up):

Please specify three parameters:
1. The name and path to the XML file.
2. The 
name and path to the XSL file.
3. The name of the output file.

Let's try it again:

So, if the XML and XSL files are placed in the same folder as our application, you can use the following syntax to run the application:

$ java addressBookConverter addresses.xml addresses.xsl result.txt

And here's what you should see:

Contact information for "Sherlock Holmes, World's Greatest Detective"
Mailing 
address: 221B BakerStreet, London, England
Phone: 123 6789
Email address: sherlock@holmes.domain.com
Web 
site URL: http://www.method_and_madness.com/

Let's look at the code in detail.

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