package fr.in2p3.jsaga.helpers.xslt;
   
   import fr.in2p3.jsaga.Base;
   import fr.in2p3.jsaga.EngineProperties;
   
   import javax.xml.transform.*;
   import javax.xml.transform.stream.StreamSource;
   import java.io.File;
   import java.io.InputStream;
  import java.util.*;
  
  /* ***************************************************
  * *** Centre de Calcul de l'IN2P3 - Lyon (France) ***
  * ***             http://cc.in2p3.fr/             ***
  * ***************************************************
  * File:   XSLTransformerFactory
  * Author: Sylvain Reynaud (sreynaud@in2p3.fr)
  * Date:   6 mai 2007
  * ***************************************************
  * Description:                                      */
  /**
   * A thread-safe factory of Transformer, which caches the parsing of stylesheets
   */
  public class XSLTransformerFactory {
      private static XSLTransformerFactory _instance;
  
      private TransformerFactory m_factory;
      private Map m_templatesMap;
      private File m_debugBaseDir;
  
      public static XSLTransformerFactory getInstance() {
          if (_instance == null) {
              _instance = new XSLTransformerFactory();
          }
          return _instance;
      }
      private XSLTransformerFactory() {
          m_factory = TransformerFactory.newInstance();
          if ("net.sf.saxon.TransformerFactoryImpl".equals(m_factory.getClass().getName())) {
              // force using XALAN because SAXON is too restrictive for stylesheet jsaga-default-contexts-merge.xsl
              System.setProperty("javax.xml.transform.TransformerFactory", "org.apache.xalan.processor.TransformerFactoryImpl");
              m_factory = TransformerFactory.newInstance();
          }
          m_templatesMap = new HashMap();
          m_debugBaseDir = new File(Base.JSAGA_VAR, "debug");
          if (Base.DEBUG && !m_debugBaseDir.exists()) {
              m_debugBaseDir.mkdir();
          }
      }
  
      public XSLTransformer getCached(String xslFile) throws TransformerConfigurationException {
          return getCached(xslFile, null, null);
      }
      public XSLTransformer getCached(String xslFile, URIResolver uriResolver) throws TransformerConfigurationException {
          return getCached(xslFile, uriResolver, null);
      }
      public XSLTransformer getCached(String xslFile, Map parameters) throws TransformerConfigurationException {
          return getCached(xslFile, null, parameters);
      }
      public XSLTransformer getCached(String xslFile, URIResolver uriResolver, Map parameters) throws TransformerConfigurationException {
          Templates templates = (Templates) m_templatesMap.get(xslFile);
          if (templates == null) {
              templates = m_factory.newTemplates(this.getXSLSource(xslFile));
              m_templatesMap.put(xslFile, templates);
          }
          return getXSLTransformer(
                  xslFile,
                  templates.newTransformer(),
                  (uriResolver!=null ? uriResolver : new TransformerURIResolver()),
                  (parameters!=null ? parameters : new HashMap()));
      }
  
      public XSLTransformer create(String xslFile) throws TransformerConfigurationException {
          return create(xslFile, null, null);
      }
      public XSLTransformer create(String xslFile, URIResolver uriResolver) throws TransformerConfigurationException {
          return create(xslFile, uriResolver, null);
      }
      public XSLTransformer create(String xslFile, Map parameters) throws TransformerConfigurationException {
          return create(xslFile, null, parameters);
      }
      public XSLTransformer create(String xslFile, URIResolver uriResolver, Map parameters) throws TransformerConfigurationException {
          return getXSLTransformer(
                  xslFile,
                  m_factory.newTransformer(this.getXSLSource(xslFile)),
                  (uriResolver!=null ? uriResolver : new TransformerURIResolver()),
                  (parameters!=null ? parameters : new HashMap()));
      }
  
      private Source getXSLSource(String xslFile) throws TransformerConfigurationException {
          InputStream stream = XSLTransformerFactory.class.getClassLoader().getResourceAsStream(xslFile);
          if (stream != null) {
              return new StreamSource(stream);
          } else {
              throw new TransformerConfigurationException("Stylesheet not found: "+xslFile);
          }
      }
  
      private XSLTransformer getXSLTransformer(String xslFile, Transformer transformer, URIResolver uriResolver, Map parameters) {
         // set transformer
         transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
         transformer.setURIResolver(uriResolver);
         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());
         }
         for (Iterator it=parameters.entrySet().iterator(); it.hasNext(); ) {
             Map.Entry entry = (Map.Entry) it.next();
             transformer.setParameter((String) entry.getKey(), entry.getValue());
         }
         // set debug file
         String debugFileName = new File(xslFile).getName()+".xml";
         File debugFile = new File(m_debugBaseDir, debugFileName);
         // encapsulate
         return new XSLTransformer(transformer, debugFile);
     }
 }