001    /*
002     * Copyright (c) 2006 Henri Sivonen
003     *
004     * Permission is hereby granted, free of charge, to any person obtaining a 
005     * copy of this software and associated documentation files (the "Software"), 
006     * to deal in the Software without restriction, including without limitation 
007     * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
008     * and/or sell copies of the Software, and to permit persons to whom the 
009     * Software is furnished to do so, subject to the following conditions:
010     *
011     * The above copyright notice and this permission notice shall be included in 
012     * all copies or substantial portions of the Software.
013     *
014     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
015     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
016     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
017     * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
018     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
019     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
020     * DEALINGS IN THE SOFTWARE.
021     */
022    
023    package fi.iki.hsivonen.xml;
024    
025    import java.util.Arrays;
026    
027    import org.xml.sax.Attributes;
028    import org.xml.sax.SAXException;
029    
030    import gnu.xml.pipeline.EventConsumer;
031    import gnu.xml.pipeline.EventFilter;
032    
033    public class BlockPassFilter extends EventFilter {
034        /**
035         * The XHTML namespace URI
036         */
037        private final static String XHTML_NS = "http://www.w3.org/1999/xhtml";
038    
039        private final static String[] BLOCK_ELEMENTS = { "address", "blockquote",
040                "div", "dl", "h1", "h2", "h3", "h4", "h5", "h6", "ol", "p",
041                "table", "ul" };
042    
043        private int depth;
044    
045        public BlockPassFilter(EventConsumer next) {
046            super(next);
047            setContentHandler(this);
048        }
049    
050        private static boolean isBlock(String name) {
051            return Arrays.binarySearch(BLOCK_ELEMENTS, name) > -1;
052        }
053        
054        /**
055         * @see gnu.xml.pipeline.EventFilter#characters(char[], int, int)
056         */
057        public void characters(char[] arg0, int arg1, int arg2) throws SAXException {
058            if (depth > 0) {
059                super.characters(arg0, arg1, arg2);
060            }
061        }
062    
063        /**
064         * @see gnu.xml.pipeline.EventFilter#endElement(java.lang.String,
065         *      java.lang.String, java.lang.String)
066         */
067        public void endElement(String arg0, String arg1, String arg2)
068                throws SAXException {
069            if (depth > 0) {
070                super.endElement(arg0, arg1, arg2);
071            }
072            depth--;
073        }
074    
075        /**
076         * @see gnu.xml.pipeline.EventFilter#ignorableWhitespace(char[], int, int)
077         */
078        public void ignorableWhitespace(char[] arg0, int arg1, int arg2)
079                throws SAXException {
080            if (depth > 0) {
081                super.ignorableWhitespace(arg0, arg1, arg2);
082            }
083        }
084    
085        /**
086         * @see gnu.xml.pipeline.EventFilter#processingInstruction(java.lang.String,
087         *      java.lang.String)
088         */
089        public void processingInstruction(String arg0, String arg1)
090                throws SAXException {
091            if (depth > 0) {
092                super.processingInstruction(arg0, arg1);
093            }
094        }
095    
096        /**
097         * @see gnu.xml.pipeline.EventFilter#startDocument()
098         */
099        public void startDocument() throws SAXException {
100            depth = -1;
101            super.startDocument();
102        }
103    
104        /**
105         * @see gnu.xml.pipeline.EventFilter#startElement(java.lang.String,
106         *      java.lang.String, java.lang.String, org.xml.sax.Attributes)
107         */
108        public void startElement(String namespaceURI, String localName,
109                String qName, Attributes atts) throws SAXException {
110            if (depth > 0) {
111                super.startElement(namespaceURI, localName, qName, atts);
112                depth++;
113            } else if (XHTML_NS.equals(namespaceURI) && isBlock(localName)) {
114                super.startElement(namespaceURI, localName, qName, atts);
115                depth = 1;
116            }
117        }
118    
119    }