/*
* JBoss, Home of Professional Open Source
* Copyright 2006, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.deployers.vfs.spi.deployer;

import java.io.InputStream;

import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamSource;

import org.jboss.deployers.vfs.spi.structure.VFSDeploymentUnit;
import org.jboss.util.xml.DOMWriter;
import org.jboss.util.xml.JBossErrorHandler;
import org.jboss.virtual.VirtualFile;
import org.w3c.dom.Document;

/**
 * SchemaResolverDeployer.
 * 
 * @param <T> the expected type 
 * @author <a href="adrian@jboss.com">Adrian Brock</a>
 * @version $Revision: 1.1 $
 */
public abstract class XSLDeployer<T> extends JAXPDeployer<T>
{
   /** The xsl resource path */
   protected String xslPath;

   /** The templates */
   private Templates templates;

   /**
    * Create a new XSLDeployer.
    * 
    * @param deploymentType the deployment type
    * @throws IllegalArgumentException for a null deployment type
    */
   public XSLDeployer(Class<T> deploymentType)
   {
      super(deploymentType);
   }

   /**
    * Get the xslPath.
    * 
    * @return the xslPath.
    */
   public String getXSLPath()
   {
      return xslPath;
   }

   /**
    * Set the xslPath.
    * 
    * @param xslPath the xslPath.
    */
   public void setXSLPath(String xslPath)
   {
      this.xslPath = xslPath;
   }

   /**
    * Get the templates.
    * 
    * @return the templates.
    * @throws IllegalStateException if the create method has not been invoked
    */
   public Templates getTemplates()
   {
      if (templates == null)
         throw new IllegalStateException("Templates have not been constructed");
      return templates;
   }

   /**
    * Create lifecycle
    * 
    * @throws Exception for any problem
    */
   public void create() throws Exception
   {
      super.create();

      TransformerFactory tf = TransformerFactory.newInstance();
      
      InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(xslPath);
      try
      {
         StreamSource ss = new StreamSource(is);
         ss.setSystemId(xslPath);
         templates = tf.newTemplates(ss);
         log.debug("Created templates: " + templates);
      }
      finally
      {
         try
         {
            is.close();
         }
         catch (Exception ignored)
         {
         }
      }
   }

   /**
    * Destroy lifecycle
    */
   public void destroy()
   {
      super.destroy();
      templates = null;
   }
   
   @Override
   protected T parse(VFSDeploymentUnit unit, VirtualFile file, T root) throws Exception
   {
      if (file == null)
         throw new IllegalArgumentException("Null file");

      Document document = doParse(unit, file);

      Transformer trans = getTemplates().newTransformer();
      trans.setErrorListener(new JBossErrorHandler(file.getPathName(), null));
      Source s = new DOMSource(document);
      s.setSystemId(file.toURI().toString());
      DOMResult r = new DOMResult();
      setParameters(trans);
      
      trans.transform(s, r);
      
      document = (Document) r.getNode();
      String docStr = DOMWriter.printNode(document, true);
      log.debug("Transformed " + file.getPathName() + " into " + docStr);
      
      return parse(unit, file, document);
   }

   /**
    * Set parameters for the transformation
    * 
    * @param trans the transformer
    * @throws Exception for any problem
    */
   protected void setParameters(Transformer trans) throws Exception
   {
      // nothing by default
   }
}