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 from the DOM tree.
034 *  This is very useful for cleaning away all of the XHTML.
035 *
036 *  @since  2.4
037 */
038public class CleanTextRenderer
039    extends WikiRenderer
040{
041    private static final String ALL_TEXT_NODES = "//text()";
042
043    protected static final Logger log = Logger.getLogger( CleanTextRenderer.class );
044
045    /**
046     *  Create a renderer.
047     *
048     *  @param context A WikiContext in which the rendering will take place.
049     *  @param doc The WikiDocument which shall be rendered.
050     */
051    public CleanTextRenderer( WikiContext context, WikiDocument doc )
052    {
053        super( context, doc );
054    }
055
056    /**
057     *  {@inheritDoc}
058     */
059    public String getString() throws IOException
060    {
061        StringBuilder sb = new StringBuilder();
062
063        try
064        {
065            XPath xp = XPath.newInstance( ALL_TEXT_NODES );
066
067            List nodes = xp.selectNodes(m_document.getDocument());
068
069            for( Iterator i = nodes.iterator(); i.hasNext(); )
070            {
071                Object el = i.next();
072
073                if( el instanceof Text )
074                {
075                    sb.append( ((Text)el).getValue() );
076                }
077            }
078        }
079        catch( JDOMException e )
080        {
081            log.error("Could not parse XPATH expression");
082            throw new IOException( e.getMessage() );
083        }
084
085        return sb.toString();
086    }
087}