001/* 
002    Licensed to the Apache Software Foundation (ASF) under one
003    or more contributor license agreements.  See the NOTICE file
004    distributed with this work for additional information
005    regarding copyright ownership.  The ASF licenses this file
006    to you under the Apache License, Version 2.0 (the
007    "License"); you may not use this file except in compliance
008    with the License.  You may obtain a copy of the License at
009
010       http://www.apache.org/licenses/LICENSE-2.0
011
012    Unless required by applicable law or agreed to in writing,
013    software distributed under the License is distributed on an
014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015    KIND, either express or implied.  See the License for the
016    specific language governing permissions and limitations
017    under the License.  
018 */
019package org.apache.wiki.render;
020
021import java.io.IOException;
022import java.util.Iterator;
023import java.util.List;
024
025import org.apache.log4j.Logger;
026import org.apache.wiki.WikiContext;
027import org.apache.wiki.parser.WikiDocument;
028import org.jdom2.JDOMException;
029import org.jdom2.Text;
030import org.jdom2.xpath.XPath;
031
032/**
033 *  A simple renderer that just renders all the text() nodes
034 *  from the DOM tree.  This is very useful for cleaning away
035 *  all of the XHTML.
036 *  
037 *  @since  2.4
038 */
039public class CleanTextRenderer
040    extends WikiRenderer
041{
042    private static final String ALL_TEXT_NODES = "//text()";
043    
044    protected static final Logger log = Logger.getLogger( CleanTextRenderer.class );
045    
046    /**
047     *  Create a renderer.
048     *  
049     *  @param context {@inheritDoc}
050     *  @param doc {@inheritDoc}
051     */
052    public CleanTextRenderer( WikiContext context, WikiDocument doc )
053    {
054        super( context, doc );
055    }
056    
057    /**
058     *  {@inheritDoc}
059     */
060    public String getString()
061        throws IOException
062    {
063        StringBuilder sb = new StringBuilder();
064        
065        try
066        {
067            XPath xp = XPath.newInstance( ALL_TEXT_NODES );
068        
069            List nodes = xp.selectNodes(m_document.getDocument());
070            
071            for( Iterator i = nodes.iterator(); i.hasNext(); )
072            {
073                Object el = i.next();
074                
075                if( el instanceof Text )
076                {
077                    sb.append( ((Text)el).getValue() );
078                }
079            }
080        }
081        catch( JDOMException e )
082        {
083            log.error("Could not parse XPATH expression");
084            throw new IOException( e.getMessage() );
085        }
086    
087        return sb.toString();
088    }
089}