xmlutilities.java

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/*====================================================================*\

XmlUtilities.java

XML utilities class.

------------------------------------------------------------------------

This file is part of FuncPlotter, a combined Java application and applet
for plotting explicit functions in one variable.
Copyright 2005-2007 Andy Morgan-Richards.

FuncPlotter is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.

This program 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 for more details.

You should have received a copy of the GNU General Public License along
with this program.  If not, see <http://www.gnu.org/licenses/>.

\*====================================================================*/


// PACKAGE


package xml;

//----------------------------------------------------------------------


// IMPORTS


import exception.AppException;

import java.io.ByteArrayInputStream;
import java.io.CharArrayReader;
import java.io.InputStream;
import java.io.IOException;
import java.io.StringReader;

import java.net.URI;

import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

//----------------------------------------------------------------------


// XML UTILITIES CLASS


public class XmlUtilities
{

////////////////////////////////////////////////////////////////////////
//  Constants
////////////////////////////////////////////////////////////////////////

    private interface AttrName
    {
        String  INDEX   = "index";
        String  XMLNS   = "xmlns";
    }

////////////////////////////////////////////////////////////////////////
//  Enumeration types
////////////////////////////////////////////////////////////////////////


    // ERROR IDENTIFIERS


    private enum ErrorId
        implements AppException.Id
    {

    ////////////////////////////////////////////////////////////////////
    //  Constants
    ////////////////////////////////////////////////////////////////////

        FAILED_TO_INSTANTIATE_DOCUMENT_BUILDER_FACTORY
        ( "Failed to instantiate a DOM document builder factory." ),
        FAILED_TO_CREATE_DOCUMENT_BUILDER
        ( "Failed to create a DOM document builder." ),
        ERROR_PARSING_FILE
        ( "An error occurred while parsing the file." );

    ////////////////////////////////////////////////////////////////////
    //  Constructors
    ////////////////////////////////////////////////////////////////////

        private ErrorId( String message )
        {
            this.message = message;
        }

        //--------------------------------------------------------------

    ////////////////////////////////////////////////////////////////////
    //  Instance methods : AppException.Id interface
    ////////////////////////////////////////////////////////////////////

        public String getMessage( )
        {
            return message;
        }

        //--------------------------------------------------------------

    ////////////////////////////////////////////////////////////////////
    //  Instance variables
    ////////////////////////////////////////////////////////////////////

        private String  message;

    }

    //==================================================================

////////////////////////////////////////////////////////////////////////
//  Constructors
////////////////////////////////////////////////////////////////////////

    private XmlUtilities( )
    {
    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Class methods
////////////////////////////////////////////////////////////////////////

    public static String getElementPath( Element element )
    {
        List<String> strs = new ArrayList<String>( );
        while ( element != null )
        {
            strs.add( element.getNodeName( ) );
            Node parent = element.getParentNode( );
            element = (parent instanceof Element) ? (Element)parent : null;
        }

        StringBuilder buffer = new StringBuilder( strs.size( ) << 4 );
        for ( int i = strs.size( ) - 1; i >= 0; --i )
        {
            buffer.append( strs.get( i ) );
            if ( i > 0 )
                buffer.append( '.' );
        }
        return buffer.toString( );
    }

    //------------------------------------------------------------------

    public static DocumentBuilder createDocumentBuilder( boolean validate )
        throws AppException
    {
        try
        {
            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance( );
            docBuilderFactory.setValidating( validate );
            docBuilderFactory.setNamespaceAware( true );
            return docBuilderFactory.newDocumentBuilder( );
        }
        catch ( FactoryConfigurationError e )
        {
            throw new AppException( ErrorId.FAILED_TO_INSTANTIATE_DOCUMENT_BUILDER_FACTORY, e );
        }
        catch ( ParserConfigurationException e )
        {
            throw new AppException( ErrorId.FAILED_TO_CREATE_DOCUMENT_BUILDER, e );
        }
    }

    //------------------------------------------------------------------

    public static Document createDOMDocument( byte[] data )
        throws AppException
    {
        return createDOMDocument( data, null, null );
    }

    //------------------------------------------------------------------

    public static Document createDOMDocument( byte[]       data,
                                              URI          systemId,
                                              ErrorHandler errorHandler )
        throws AppException
    {
        InputSource inputSource = new InputSource( new ByteArrayInputStream( data ) );
        inputSource.setEncoding( XmlConstants.UTF8_STR );
        return createDOMDocument( inputSource, systemId, errorHandler );
    }

    //------------------------------------------------------------------

    public static Document createDOMDocument( char[] data )
        throws AppException
    {
        return createDOMDocument( data, null, null );
    }

    //------------------------------------------------------------------