/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999,2000 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 "Xerces" 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) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.html.dom;





import java.util.Vector;

import org.w3c.dom.*;

import org.w3c.dom.html.*;

import org.xml.sax.*;

import org.apache.xerces.dom.TextImpl;

import org.apache.xerces.dom.ElementImpl;

import org.apache.xerces.dom.ProcessingInstructionImpl;





/**

 * This is a SAX document handler that is used to build an HTML document.

 * It can build a document from any SAX parser, but is specifically tuned

 * for working with the OpenXML HTML parser.

 * 

 * 

 * @version $Revision: 1.3 $ $Date: 2000/02/10 04:00:09 $

 * @author <a href="mailto:arkin@openxml.org">Assaf Arkin</a>

 */

public class HTMLBuilder

    implements DocumentHandler

{





    /**

     * The document that is being built.

     */

    protected HTMLDocumentImpl    _document;

    

    

    /**

     * The current node in the document into which elements, text and

     * other nodes will be inserted. This starts as the document iself

     * and reflects each element that is currently being parsed.

     */

    protected ElementImpl        _current;

    

    /**

     * A reference to the current locator, this is generally the parser

     * itself. The locator is used to locate errors and identify the

     * source locations of elements.

     */

    private Locator         _locator;





    /**

     * Applies only to whitespace appearing between element tags in element content,

     * as per the SAX definition, and true by default.

     */

    private boolean         _ignoreWhitespace = true;





    /**

     * Indicates whether finished building a document. If so, can start building

     * another document. Must be initially true to get the first document processed.

     */

    private boolean         _done = true;





    /**    

     * The document is only created the same time as the document element, however, certain

     * nodes may precede the document element (comment and PI), and they are accumulated

     * in this vector.

     */

    protected Vector         _preRootNodes;



    

    public void startDocument()

        throws SAXException

    {

        if ( ! _done )

	    throw new SAXException( "HTM001 State error: startDocument fired twice on one builder." );

	_document = null;

	_done = false;

    }





    public void endDocument()

        throws SAXException

    {

        if ( _document == null )

            throw new SAXException( "HTM002 State error: document never started or missing document element." );

	if ( _current != null )

	    throw new SAXException( "HTM003 State error: document ended before end of document element." );

        _current = null;

	_done = true;

    }





    public synchronized void startElement( String tagName, AttributeList attrList )

        throws SAXException

    {

        ElementImpl elem;

        int         i;

        

	if ( tagName == null )

	    throw new SAXException( "HTM004 Argument 'tagName' is null." );



	// If this is the root element, this is the time to create a new document,

	// because only know we know the document element name and namespace URI.

	if ( _document == null )

	{

	    // No need to create the element explicitly.

	    _document = new HTMLDocumentImpl();

	    elem = (ElementImpl) _document.getDocumentElement();

	    _current = elem;

	    if ( _current == null )

		throw new SAXException( "HTM005 State error: Document.getDocumentElement returns null." );



	    // Insert nodes (comment and PI) that appear before the root element.

	    if ( _preRootNodes != null )

	    {

		for ( i = _preRootNodes.size() ; i-- > 0 ; )

		    _document.insertBefore( (Node) _preRootNodes.elementAt( i ), elem );

		_preRootNodes = null;

	    }

	     

	}

	else

	{

	    // This is a state error, indicates that document has been parsed in full,

	    // or that there are two root elements.

	    if ( _current == null )

		throw new SAXException( "HTM006 State error: startElement called after end of document element." );

	    elem = (ElementImpl) _document.createElement( tagName );

	    _current.appendChild( elem );

	    _current = elem;

	}



	// Add the attributes (specified and not-specified) to this element.

        if ( attrList != null )

        {

            for ( i = 0 ; i < attrList.getLength() ; ++ i )

                elem.setAttribute( attrList.getName( i ), attrList.getValue( i ) );

        }

    }



    

    public void endElement( String tagName )

        throws SAXException

    {



        if ( _current == null )

            throw new SAXException( "HTM007 State error: endElement called with no current node." );

	if ( ! _current.getNodeName().equals( tagName ) )

	    throw new SAXException( "HTM008 State error: mismatch in closing tag name " + tagName + "\n" + tagName);



	// Move up to the parent element. When you reach the top (closing the root element).

	// the parent is document and current is null.

	if ( _current.getParentNode() == _current.getOwnerDocument() )

	    _current = null;

	else

	    _current = (ElementImpl) _current.getParentNode();

    }





    public void characters( String text )

        throws SAXException

    {

	if ( _current == null )

            throw new SAXException( "HTM009 State error: character data found outside of root element." );

	_current.appendChild( new TextImpl( _document, text ) );

    }



    

    public void characters( char[] text, int start, int length )

        throws SAXException

    {

	if ( _current == null )

            throw new SAXException( "HTM010 State error: character data found outside of root element." );

	_current.appendChild( new TextImpl( _document, new String( text, start, length ) ) );

    }

    

    

    public void ignorableWhitespace( char[] text, int start, int length )

        throws SAXException

    {

        Node    node;

        

        if ( ! _ignoreWhitespace )

	    _current.appendChild( new TextImpl( _document, new String( text, start, length ) ) );

     }

    

    

    public void processingInstruction( String target, String instruction )

        throws SAXException

    {

        Node    node;

        

	// Processing instruction may appear before the document element (in fact, before the

	// document has been created, or after the document element has been closed.

        if ( _current == null && _document == null )

	{

	    if ( _preRootNodes == null )

		_preRootNodes = new Vector();

	    _preRootNodes.addElement( new ProcessingInstructionImpl( null, target, instruction ) );

	}

	else

        if ( _current == null && _document != null )

	    _document.appendChild( new ProcessingInstructionImpl( _document, target, instruction ) );

	else

	    _current.appendChild( new ProcessingInstructionImpl( _document, target, instruction ) );

    }

    

    

    public HTMLDocument getHTMLDocument()

    {

        return (HTMLDocument) _document;

    }



    

    public void setDocumentLocator( Locator locator )

    {

        _locator = locator;

    }





}

