/* ======================================================================
The Bodington System Software License, Version 1.0

Copyright (c) 2001 The University of Leeds.  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 acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.

4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.

5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
EVENT SHALL THE UNIVERSITY OF LEEDS 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 was originally created by the University of Leeds and may contain voluntary
contributions from others.  For more information on the Bodington Open Source Project, please
see http://bodington.org/

====================================================================== */

package org.bodington.xml;

// Imported JAVA API for XML Parsing classes
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.xml.sax.InputSource;

import java.net.URL;
import java.io.File;
import java.io.InputStream;
import java.io.StringReader;

import org.apache.log4j.Logger;
import org.bodington.server.BuildingServerException;

import org.w3c.dom.Document;

/**
 * XML utility class for creating DOMs.
 * @author Antony Corfield; Colin Tatham
 */
public class DOMFactory
{
    
    private static DocumentBuilderFactory factory;
    private static Logger log = Logger.getLogger( DOMFactory.class );
    
    static
    {
        factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware( true );
    }

    /**
     * Gets a document builder from the factory.
     * @return A new instance of a DocumentBuilder
     */
    private static synchronized DocumentBuilder getDocumentBuilder()
    {
        DocumentBuilder builder = null;
        try
        {
            builder = factory.newDocumentBuilder();
            builder.setErrorHandler( new ErrorListener() );
        }
        catch ( ParserConfigurationException e )
        {
            String message = "DOMFactory, static initialization: "
                + "Parser with specified options cannot be built!";
            log.error( message, e );
            System.err.print( "FATAL: " + message
                + " Could not initialize DOMFactory." );
            System.exit( -1 );
        }

        return builder;
    }

    /**
     * Create a new DOM document.
     * @return A new instance of a Document
     */
    public static Document newDocument()
    {
        return getDocumentBuilder().newDocument();
    }

    /**
     * Create a new DOM Document by parsing an XML resource specified by a URL.
     * @param resource The URL defining the resource location
     * @return A new instance of a Document
     * @throws BuildingServerException
     */
    public static Document parse( URL resource ) throws BuildingServerException
    {
        try
        {
            return parse( new File( resource.getPath() ) );
        }
        catch ( NullPointerException npe )
        {
            String message = "Error creating file from URL: " + npe.getMessage();
            log.debug( message );
            throw new BuildingServerException( message );
        }
    }

    /**
     * Create a new DOM Document by parsing XML contained in a File.
     * @param file The File containing XML
     * @return A new instance of a Document
     * @throws BuildingServerException
     */
    public static Document parse( File file ) throws BuildingServerException
    {
        Document document = null;
        try
        {
            DocumentBuilder builder = getDocumentBuilder();
            document = builder.parse( file );
        }
        catch ( Exception e )
        {
            log.debug( "Cannot parse XML file: " + e.getMessage() );
            throw new BuildingServerException( e.getMessage() );
        }

        return document;
    }

    /**
     * Create a new DOM Document by parsing XML from an InputStream.
     * @param inStream InputStream of XML
     * @return A new instance of a Document
     * @throws BuildingServerException
     */
    public static Document parse( InputStream inStream )
        throws BuildingServerException
    {
        Document document = null;
        try
        {
            DocumentBuilder builder = getDocumentBuilder();
            document = builder.parse( inStream );
        }
        catch ( Exception e )
        {
            log.debug( "Cannot parse XML InputStream: " + e.getMessage() );
            throw new BuildingServerException( e.getMessage() );
        }

        return document;
    }

    /**
     * Create a new DOM Document by parsing XML markup in a String.
     * @param data The String of XML markup
     * @return A new instance of a Document
     * @throws BuildingServerException
     */
    public static Document parse( String data ) throws BuildingServerException
    {
        Document document = null;
        try
        {
            DocumentBuilder builder = getDocumentBuilder();
            document = builder
                .parse( new InputSource( new StringReader( data ) ) );
        }
        catch ( Exception e )
        {
            log.debug( "Cannot parse XML string data: " + e.getMessage() );
            throw new BuildingServerException( e.getMessage() );
        }

        return document;
    }
}