/*
    * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/dom/DOMFactoryXALANImpl.java,v 1.7 2005/12/02 12:35:47 hkollmann Exp $
    * $Revision: 1.7 $
    * $Date: 2005/12/02 12:35:47 $
    *
    * DbForms - a Rapid Application Development Framework
    * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
    *
    * This library 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 library 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 library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */
  
  package org.dbforms.dom;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.xpath.domapi.XPathEvaluatorImpl;
  
  import org.dbforms.util.Util;
  
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.w3c.dom.xpath.XPathEvaluator;
  
  import org.xml.sax.InputSource;
  
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.StringReader;
  import java.io.StringWriter;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.transform.Transformer;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamResult;
  
  
  
  /***
   * special implementation of the DOMFactory for xerces/xalan implementation,
   * This is the default class used by DOMFactory!
   *
   * @author Henner Kollmann
   */
  public class DOMFactoryXALANImpl extends AbstractDOMFactoryImpl
            {
     private DocumentBuilder builder     = createDOMBuilder();
     private Log             logCat      = LogFactory.getLog(this.getClass().getName());
     private Transformer     transformer = createDOMWriter();
  
     /***
      * Creates a string representation of the given DOMDocument
      *
      * @param doc The document to transform
      *
      * @return string representation
      */
     public String DOM2String(Document doc) {
        StringWriter writer = new StringWriter();
  
        try {
           StreamResult result = new StreamResult(writer);
           DOMSource    source = new DOMSource(doc);
           transformer.transform(source, result);
        } catch (Exception e) {
           logCat.error("write", e);
        }
  
        String s = writer.toString();
  
        return s;
     }
  
  
     /***
      * Creates an new DOMDocument from the given string
      *
      * @param data the string to parse
      *
      * @return The new DOMDocument
      */
     public Document String2DOM(String data) {
        Document doc = null;
  
        if (!Util.isNull(data)) {
          // String parsen
          try {
             // String parsen
             InputSource in = new InputSource(new StringReader(data));
             doc = builder.parse(in);
          } catch (Exception e) {
             logCat.error(e.getMessage() + "\n" + data);
          }
       }
 
       return doc;
    }
 
 
    /***
     * Creates a new empty DOMDocument
     *
     * @return An empty DOMDocument
     */
    public Document newDOMDocument() {
       return builder.newDocument();
    }
 
 
    /***
     * returns an new created XPathEvaluator
     *
     * @return the new XPathEvaluator
     */
    public XPathEvaluator newXPathEvaluator() {
       return new XPathEvaluatorImpl();
    }
 
 
    /***
     * Reads a DOMDocument from given url
     *
     * @param in the url to read from
     *
     * @return The new parsed DOMDocument
     */
    public Document read(InputStream in) {
       Document doc = null;
 
       try {
          InputSource src = new InputSource(in);
          doc = builder.parse(src);
       } catch (Exception e) {
          logCat.error(e);
       }
 
       return doc;
    }
 
 
    /***
     * Writes a DOMDocument into an OutputStream
     *
     * @param out OutputStream to write into
     * @param root The Ddcument to write
     */
    public void write(OutputStream out,
                      Element      root) {
       try {
          StreamResult result = new StreamResult(out);
          DOMSource    source = new DOMSource(root);
          transformer.transform(source, result);
       } catch (Exception e) {
          logCat.error("write", e);
       }
    }
 
 
    private DocumentBuilder createDOMBuilder() {
       DocumentBuilder res = null;
 
       try {
          // Init DOM
          DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
          dfactory.setValidating(false);
          dfactory.setNamespaceAware(false);
          res = dfactory.newDocumentBuilder();
       } catch (Exception e) {
          logCat.error(e);
       }
 
       return res;
    }
 
 
    private Transformer createDOMWriter() {
       Transformer res = null;
 
       try {
          TransformerFactory transFactory = TransformerFactory.newInstance();
          res = transFactory.newTransformer();
       } catch (Exception e) {
          logCat.error("createDOMWriter", e);
       }
 
       return res;
    }
 }