package fr.in2p3.jsaga.helpers.xslt;
   
   import fr.in2p3.jsaga.Base;
   import fr.in2p3.jsaga.EngineProperties;
   import fr.in2p3.jsaga.helpers.XMLFileParser;
   import org.w3c.dom.Document;
   
   import javax.xml.parsers.DocumentBuilderFactory;
   import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.transform.*;
  import javax.xml.transform.dom.DOMResult;
  import javax.xml.transform.dom.DOMSource;
  import java.io.*;
  import java.util.Iterator;
  import java.util.Map;
  
  /* ***************************************************
   * *** Centre de Calcul de l'IN2P3 - Lyon (France) ***
   * ***             http://cc.in2p3.fr/             ***
   * ***************************************************
   * File:   CompiledTransformer
   * Author: Sylvain Reynaud (sreynaud@in2p3.fr)
   * ***************************************************
   * Description:                                      */
  
  /*
   <plugins>
       <plugin>
           <groupId>org.codehaus.mojo</groupId>
           <artifactId>maven-plugin-xsltc</artifactId>
           <version>1.0-SNAPSHOT</version>
           <executions>
               <execution>
                   <id>xsltc</id>
                   <goals><goal>compile</goal></goals>
               </execution>
           </executions>
           <configuration>
               <stylesheets>
                   <stylesheet>${basedir}/resources/xsl/jsaga-default-contexts-merge.xsl</stylesheet>
                   <stylesheet>${basedir}/resources/xsl/jsaga-default-contexts.xsl</stylesheet>
               </stylesheets>
               <packageName>fr.in2p3.jsaga.generated.xsl</packageName>
               <outputDirectory>${project.build.directory}/generated-classes</outputDirectory>
           </configuration>
       </plugin>
   </plugins>
   <resources>
       <resource><directory>${project.build.directory}/generated-classes</directory></resource>
       <resource><directory>resources</directory></resource>
   </resources>
   */
  public class CompiledTransformer {
      private Templates m_translet;
  
      public CompiledTransformer(String packageName, String transletName) throws TransformerConfigurationException, IOException {
          // load translet
          TransformerFactory tFactory;
          // thread-safe instanciation not supported by JDK 1.5
  //        tFactory = TransformerFactory.newInstance("org.apache.xalan.xsltc.trax.TransformerFactoryImpl", CompiledTransformer.class.getClassLoader());
          synchronized (this) {
              // save transformer implementation
              final String TRANSFORMER_IMPL = "javax.xml.transform.TransformerFactory";
              String savImpl = System.getProperty(TRANSFORMER_IMPL);
              System.setProperty(TRANSFORMER_IMPL, "org.apache.xalan.xsltc.trax.TransformerFactoryImpl");
  
              // create transformer factory
              tFactory = TransformerFactory.newInstance();
  
              // restore transformer implementation
              if (savImpl != null) {
                  System.setProperty(TRANSFORMER_IMPL, savImpl);
              } else {
                  System.getProperties().remove(TRANSFORMER_IMPL);
              }
          }
          tFactory.setAttribute("debug", "true");
          tFactory.setAttribute("package-name", packageName);
          tFactory.setAttribute("translet-name", transletName);
          tFactory.setAttribute("use-classpath", "true");
          m_translet = tFactory.newTemplates(null);
      }
  
      public Document transformToDOM(Document xml, File debugFile) throws TransformerException, IOException {
          // create result container
          Document doc;
          try {
              doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
          } catch (ParserConfigurationException e) {
              throw new TransformerException(e);
          }
          Result result = new DOMResult(doc);
  
          // create transformer
          Transformer transformer = m_translet.newTransformer();
          transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
          transformer.setURIResolver(new TransformerURIResolver());
          transformer.setErrorListener(new XSLLogger());
          for (Iterator it = EngineProperties.getProperties().entrySet().iterator(); it.hasNext();) {
             Map.Entry entry = (Map.Entry) it.next();
             transformer.setParameter((String) entry.getKey(), entry.getValue());
         }
 
         // process
         try {
             transformer.transform(new DOMSource(xml), result);
         } catch(TransformerException e) {
             // throw the cause of exception
             transformer.getErrorListener().fatalError(e);
         }
 
         // debug
         if (Base.DEBUG && debugFile!=null) {
             ByteArrayOutputStream out = new ByteArrayOutputStream();
             XMLFileParser.dump(doc, out);
             byte[] outBytes = out.toByteArray();
             if (outBytes!=null) {
                 OutputStream f = new FileOutputStream(debugFile);
                 f.write(outBytes);
                 f.close();
             }
         }
 
         // return
         return doc;
     }
 }