/*

  * Copyright 2003-2004 Sun Microsystems, Inc.  All Rights Reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Sun designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Sun in the LICENSE file that accompanied this code.

  *

  * This code 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

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  */

 package java.util;

 import java.io.*;

 import org.xml.sax.*;

 import org.xml.sax.helpers.*;

 import org.w3c.dom.*;

 import javax.xml.parsers.*;

 import javax.xml.transform.*;

 import javax.xml.transform.dom.*;

 import javax.xml.transform.stream.*;

 /**

  * A class used to aid in Properties load and save in XML. Keeping this

  * code outside of Properties helps reduce the number of classes loaded

  * when Properties is loaded.

  *

  * @author  Michael McCloskey

  * @since   1.3

  */

 class XMLUtils {

     // XML loading and saving methods for Properties

     // The required DTD URI for exported properties

     private static final String PROPS_DTD_URI =

     "http://java.sun.com/dtd/properties.dtd";

     private static final String PROPS_DTD =

     "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +

     "<!-- DTD for properties -->"                +

     "<!ELEMENT properties ( comment?, entry* ) >"+

     "<!ATTLIST properties"                       +

         " version CDATA #FIXED \"1.0\">"         +

     "<!ELEMENT comment (#PCDATA) >"              +

     "<!ELEMENT entry (#PCDATA) >"                +

     "<!ATTLIST entry "                           +

         " key CDATA #REQUIRED>";

     /**

      * Version number for the format of exported properties files.

      */

     private static final String EXTERNAL_XML_VERSION = "1.0";

     static void load(Properties props, InputStream in)

         throws IOException, InvalidPropertiesFormatException

     {

         Document doc = null;

         try {

             doc = getLoadingDoc(in);

         } catch (SAXException saxe) {

             throw new InvalidPropertiesFormatException(saxe);

         }

         Element propertiesElement = (Element)doc.getChildNodes().item(1);

         String xmlVersion = propertiesElement.getAttribute("version");

         if (xmlVersion.compareTo(EXTERNAL_XML_VERSION) > 0)

             throw new InvalidPropertiesFormatException(

                 "Exported Properties file format version " + xmlVersion +

                 " is not supported. This java installation can read" +

                 " versions " + EXTERNAL_XML_VERSION + " or older. You" +

                 " may need to install a newer version of JDK.");

         importProperties(props, propertiesElement);

     }

     static Document getLoadingDoc(InputStream in)

         throws SAXException, IOException

     {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         dbf.setIgnoringElementContentWhitespace(true);

         dbf.setValidating(true);

         dbf.setCoalescing(true);

         dbf.setIgnoringComments(true);

         try {

             DocumentBuilder db = dbf.newDocumentBuilder();

             db.setEntityResolver(new Resolver());

             db.setErrorHandler(new EH());

             InputSource is = new InputSource(in);

             return db.parse(is);

         } catch (ParserConfigurationException x) {

             throw new Error(x);

         }

     }

     static void importProperties(Properties props, Element propertiesElement) {

         NodeList entries = propertiesElement.getChildNodes();

         int numEntries = entries.getLength();

         int start = numEntries > 0 &&

             entries.item(0).getNodeName().equals("comment") ? 1 : 0;

         for (int i=start; i<numEntries; i++) {

             Element entry = (Element)entries.item(i);

             if (entry.hasAttribute("key")) {

                 Node n = entry.getFirstChild();

                 String val = (n == null) ? "" : n.getNodeValue();

                 props.setProperty(entry.getAttribute("key"), val);

             }

         }

     }

     static void save(Properties props, OutputStream os, String comment,

                      String encoding)

         throws IOException

     {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = null;

         try {

             db = dbf.newDocumentBuilder();

         } catch (ParserConfigurationException pce) {

             assert(false);

         }

         Document doc = db.newDocument();

         Element properties =  (Element)

             doc.appendChild(doc.createElement("properties"));

         if (comment != null) {

             Element comments = (Element)properties.appendChild(

                 doc.createElement("comment"));

             comments.appendChild(doc.createTextNode(comment));

         }

         Set keys = props.keySet();

         Iterator i = keys.iterator();

         while(i.hasNext()) {

             String key = (String)i.next();

             Element entry = (Element)properties.appendChild(

                 doc.createElement("entry"));

             entry.setAttribute("key", key);

             entry.appendChild(doc.createTextNode(props.getProperty(key)));

         }

         emitDocument(doc, os, encoding);

     }

     static void emitDocument(Document doc, OutputStream os, String encoding)

         throws IOException

     {

         TransformerFactory tf = TransformerFactory.newInstance();

         Transformer t = null;

         try {

             t = tf.newTransformer();

             t.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, PROPS_DTD_URI);

             t.setOutputProperty(OutputKeys.INDENT, "yes");

             t.setOutputProperty(OutputKeys.METHOD, "xml");

             t.setOutputProperty(OutputKeys.ENCODING, encoding);

         } catch (TransformerConfigurationException tce) {

             assert(false);

         }

         DOMSource doms = new DOMSource(doc);

         StreamResult sr = new StreamResult(os);

         try {

             t.transform(doms, sr);

         } catch (TransformerException te) {

             IOException ioe = new IOException();

             ioe.initCause(te);

             throw ioe;

         }

     }

     private static class Resolver implements EntityResolver {

         public InputSource resolveEntity(String pid, String sid)

             throws SAXException

         {

             if (sid.equals(PROPS_DTD_URI)) {

                 InputSource is;

                 is = new InputSource(new StringReader(PROPS_DTD));

                 is.setSystemId(PROPS_DTD_URI);

                 return is;

             }

             throw new SAXException("Invalid system identifier: " + sid);

         }

     }

     private static class EH implements ErrorHandler {

         public void error(SAXParseException x) throws SAXException {

             throw x;

         }

         public void fatalError(SAXParseException x) throws SAXException {

             throw x;

         }

         public void warning(SAXParseException x) throws SAXException {

             throw x;

         }

     }

 }