source: trunk/gsdl3/src/java/org/greenstone/gsdl3/util/XMLTransformer.java@ 3769

/*
 *    XMLTransformer.java
 *    Copyright (C) 2002 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.greenstone.gsdl3.util;

// XML classes
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;

import javax.xml.transform.stream.StreamSource;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.dom.DOMResult;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

// other java classes
import java.io.StringReader;
import java.io.StringWriter;
import java.io.File;

/** XMLTransformer - utility class for greenstone
 *
 * transforms xml using xslt
 *
 * @author <a href="mailto:[email protected]">Katherine Don</a>
 * @version $Revision: 3572 $
 */
public class XMLTransformer {

  /** The transformer factory we're using */
    TransformerFactory t_factory_=null;
  
  /**
   * The no-arguments constructor. 
   *
   * Any exceptions thrown are caught internally
   * 
   * @return a new transformer
   * @see javax.xml.transform.TransformerFactory
   */
    public XMLTransformer() {

    // make sure we are using the xalan transformer
    System.setProperty("javax.xml.transform.TransformerFactory", "org.apache.xalan.processor.TransformerFactoryImpl");
    try {
        t_factory_ = org.apache.xalan.processor.TransformerFactoryImpl.newInstance();

    } catch (Exception e) {
        System.out.println("XMLTransformer() exception "+e.getMessage());
    }
    }

 
    
  /**
   * Transform an XML document using a XSLT stylesheet
   * 
   * @param stylesheet a filename for an XSLT stylesheet
   * @param xml_in the XML to be transformed
   * @return the transformed XML
   */
    public String transform(String stylesheet, String xml_in) {
    
    try {
        // Use the TransformerFactory to process the stylesheet Source and generate a Transformer.
        Transformer transformer = t_factory_.newTransformer(new StreamSource(stylesheet));

        // Use the Transformer to transform an XML Source and send the output to a Result object.
        StringWriter output = new StringWriter();

        transformer.transform(new StreamSource(new StringReader(xml_in)), new StreamResult(output));
        return output.toString();
    } catch (TransformerConfigurationException e) {
        System.err.println("XMLTransformer: couldn't create transformer object: "+e.getMessage());
        return "";
    } catch (TransformerException e) {
        System.err.println("XMLTransformer: couldn't transform the source: " + e.getMessage());
        return "";
    }   
    }

      public String transformToString(Document stylesheet, Node xml_in) {
      
      try {
        // Use the TransformerFactory to process the stylesheet Source and generate a Transformer.
        Transformer transformer = t_factory_.newTransformer(new DOMSource(stylesheet));
        
        // Use the Transformer to transform an XML Source and send the output to a Result object.
        StringWriter output = new StringWriter();
        
        transformer.transform(new DOMSource(xml_in), new StreamResult(output));
        return output.toString();
    } catch (TransformerConfigurationException e) {
        System.err.println("XMLTransformer: couldn't create transformer object: "+e.getMessage());
        return "";
    } catch (TransformerException e) {
        System.err.println("XMLTransformer: couldn't transform the source: " + e.getMessage());
        return "";
    }   
      }

    public Node transform(Document stylesheet, Node xml_in) {

    try {
        // Use the TransformerFactory to process the stylesheet Source and generate a Transformer.
        Transformer transformer = t_factory_.newTransformer(new DOMSource(stylesheet));

        DOMResult result = new DOMResult();
        transformer.transform(new DOMSource(xml_in), result);
        return result.getNode().getFirstChild();
    } catch (TransformerConfigurationException e) {
        System.err.println("XMLTransformer: couldn't create transformer object: "+e.getMessage());
        return null;
    } catch (TransformerException e) {
        System.err.println("XMLTransformer: couldn't transform the source: " + e.getMessage());
        return null;
    }   
      }
}