/*

 * 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;

        }

    }

}