/*
 * @(#)$Id$
 *
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 2001, Sun
 * Microsystems., http://www.sun.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * @author G. Todd Miller 
 */


package org.apache.xalan.xsltc.trax;

import java.util.Stack;
import java.util.Vector;

import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.Attributes;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Comment;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.Text;
import org.w3c.dom.Attr;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.SAXException;

import org.apache.xalan.xsltc.runtime.Constants;

public class SAX2DOM implements ContentHandler, LexicalHandler, Constants {

    private Node _root = null;
    private Document _document = null;
    private Stack _nodeStk = new Stack();
    private Vector _namespaceDecls = null;

    public SAX2DOM() throws ParserConfigurationException {
	final DocumentBuilderFactory factory = 
		DocumentBuilderFactory.newInstance();
	_document = factory.newDocumentBuilder().newDocument();
	_root = _document;
    }

    public SAX2DOM(Node root) throws ParserConfigurationException {
	_root = root;
	if (root instanceof Document) {
	  _document = (Document)root;
	}
	else if (root != null) {
	  _document = root.getOwnerDocument();
	}
	else {
	  final DocumentBuilderFactory factory = 
		DocumentBuilderFactory.newInstance();
	  _document = factory.newDocumentBuilder().newDocument();
	  _root = _document;
	}
    }

    public Node getDOM() {
	return _root;
    }

    public void characters(char[] ch, int start, int length) {
	final Node last = (Node)_nodeStk.peek();

	// No text nodes can be children of root (DOM006 exception)
	if (last != _document) {
	    final String text = new String(ch, start, length);
	    last.appendChild(_document.createTextNode(text));
	}
    }

    public void startDocument() {
	_nodeStk.push(_root);
    }

    public void endDocument() {
        _nodeStk.pop();
    }

    public void startElement(String namespace, String localName, String qName,
	Attributes attrs) 
    {
	final Element tmp = (Element)_document.createElementNS(namespace, qName);

	// Add namespace declarations first
	if (_namespaceDecls != null) {
	    final int nDecls = _namespaceDecls.size();
	    for (int i = 0; i < nDecls; i++) {
		final String prefix = (String) _namespaceDecls.elementAt(i++);

		if (prefix == null || prefix.equals(EMPTYSTRING)) {
		    tmp.setAttributeNS(XMLNS_URI, XMLNS_PREFIX,
			(String) _namespaceDecls.elementAt(i));
		}
		else {
		    tmp.setAttributeNS(XMLNS_URI, XMLNS_STRING + prefix, 
			(String) _namespaceDecls.elementAt(i));
		}
	    }
	    _namespaceDecls.clear();
	}

	// Add attributes to element
	final int nattrs = attrs.getLength();
	for (int i = 0; i < nattrs; i++) {
	    if (attrs.getLocalName(i) == null) {
		tmp.setAttribute(attrs.getQName(i), attrs.getValue(i));
	    }
	    else {
		tmp.setAttributeNS(attrs.getURI(i), attrs.getQName(i), 
		    attrs.getValue(i));
	    }
	}

	// Append this new node onto current stack node
	Node last = (Node)_nodeStk.peek();
	last.appendChild(tmp);

	// Push this node onto stack
	_nodeStk.push(tmp);
    }

    public void endElement(String namespace, String localName, String qName) {
	_nodeStk.pop();  
    }

    public void startPrefixMapping(String prefix, String uri) {
	if (_namespaceDecls == null) {
	    _namespaceDecls = new Vector(2);
	}
	_namespaceDecls.addElement(prefix);
	_namespaceDecls.addElement(uri);
    }

    public void endPrefixMapping(String prefix) {
	// do nothing
    }

    /**
     * This class is only used internally so this method should never 
     * be called.
     */
    public void ignorableWhitespace(char[] ch, int start, int length) {
    }

    /**
     * adds processing instruction node to DOM.
     */
    public void processingInstruction(String target, String data) {
	final Node last = (Node)_nodeStk.peek();
	ProcessingInstruction pi = _document.createProcessingInstruction(
		target, data);
	if (pi != null)  last.appendChild(pi);
    }

    /**
     * This class is only used internally so this method should never 
     * be called.
     */
    public void setDocumentLocator(Locator locator) {
    }

    /**
     * This class is only used internally so this method should never 
     * be called.
     */
    public void skippedEntity(String name) {
    }


    /**
     * Lexical Handler method to create comment node in DOM tree.
     */
    public void comment(char[] ch, int start, int length) {
	final Node last = (Node)_nodeStk.peek();
	Comment comment = _document.createComment(new String(ch,start,length));
	if (comment != null) last.appendChild(comment);
    }

    // Lexical Handler methods- not implemented
    public void startCDATA() { }
    public void endCDATA() { }
    public void startEntity(java.lang.String name) { }
    public void endDTD() { }
    public void endEntity(String name) { }
    public void startDTD(String name, String publicId, String systemId)
        throws SAXException { }

}