code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  import javax.xml.transform.Transformer;
  import javax.xml.transform.TransformerConfigurationException;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.stream.StreamResult;
  import javax.xml.transform.stream.StreamSource;
  
  import org.apache.xalan.trace.PrintTraceListener;
  import org.apache.xalan.trace.TraceManager;
  import org.apache.xalan.transformer.TransformerImpl;
  
  /**
   * Sample for demonstrating Xalan "trace" interface.
   * Usage: run in Trace directory: java Trace
   * For an extensions trace sample, run in extensions
   * directory: java Trace 3-java-namespace
   */
  public class Trace
  {	
    public static void main (String[] args)
  	  throws java.io.IOException, 
  			 TransformerException, TransformerConfigurationException,
  			 java.util.TooManyListenersException, 
  			 org.xml.sax.SAXException			 
    {
      String fileName = "foo";
      if (args.length > 0)
        fileName = args[0];
  
      // Set up a PrintTraceListener object to print to a file.
      java.io.FileWriter fw = new java.io.FileWriter("events.log");  
      java.io.PrintWriter pw = new java.io.PrintWriter(fw, true);
      PrintTraceListener ptl = new PrintTraceListener(pw);
  
      // Print information as each node is 'executed' in the stylesheet.
      ptl.m_traceElements = true;
      // Print information after each result-tree generation event.
      ptl.m_traceGeneration = true;
      // Print information after each selection event.
      ptl.m_traceSelection = true;
      // Print information whenever a template is invoked.
      ptl.m_traceTemplates = true;
      // Print information whenever an extension call is made.
      ptl.m_traceExtension = true;
  
      // Set up the transformation    
     	TransformerFactory tFactory = TransformerFactory.newInstance();
      Transformer transformer = tFactory.newTransformer(new StreamSource(fileName + ".xsl"));
  
      // Cast the Transformer object to TransformerImpl.
      if (transformer instanceof TransformerImpl) 
  	  {
        TransformerImpl transformerImpl = (TransformerImpl)transformer;
        // Register the TraceListener with a TraceManager associated 
        // with the TransformerImpl.
        TraceManager trMgr = transformerImpl.getTraceManager();
        trMgr.addTraceListener(ptl);
                       
        // Perform the transformation --printing information to
        // the events log during the process.
        transformer.transform
                           ( new StreamSource(fileName + ".xml"), 
                             new StreamResult(new java.io.FileWriter(fileName + ".out")) );
      }
      // Close the PrintWriter and FileWriter.
      pw.close();
      fw.close();
     	System.out.println("**The output is in " + fileName + ".out; the log is in events.log ****");	
      
    }
  }
  