001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006     *
007     * Project Info:  http://www.jfree.org/jfreechart/index.html
008     *
009     * This library is free software; you can redistribute it and/or modify it 
010     * under the terms of the GNU Lesser General Public License as published by 
011     * the Free Software Foundation; either version 2.1 of the License, or 
012     * (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but 
015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017     * License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this library; if not, write to the Free Software
021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022     * USA.  
023     *
024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025     * in the United States and other countries.]
026     *
027     * ---------------
028     * KeyHandler.java
029     * ---------------
030     * (C) Copyright 2003-2005, by Object Refinery Limited and Contributors.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: KeyHandler.java,v 1.3.2.1 2005/10/25 21:36:10 mungady Exp $
036     *
037     * Changes
038     * -------
039     * 23-Jan-2003 : Version 1 (DG);
040     *
041     */
042    
043    package org.jfree.data.xml;
044    
045    import org.xml.sax.Attributes;
046    import org.xml.sax.SAXException;
047    import org.xml.sax.helpers.DefaultHandler;
048    
049    /**
050     * A SAX handler for reading a key.
051     */
052    public class KeyHandler extends DefaultHandler implements DatasetTags {
053    
054        /** The root handler. */
055        private RootHandler rootHandler;
056    
057        /** The item handler. */
058        private ItemHandler itemHandler;
059    
060        /** Storage for the current CDATA */
061        private StringBuffer currentText;
062    
063        /** The key. */
064        //private Comparable key;
065    
066        /**
067         * Creates a new handler.
068         *
069         * @param rootHandler  the root handler.
070         * @param itemHandler  the item handler.
071         */
072        public KeyHandler(RootHandler rootHandler, ItemHandler itemHandler) {
073            this.rootHandler = rootHandler;
074            this.itemHandler = itemHandler;
075            this.currentText = new StringBuffer();
076            //this.key = null;
077        }
078    
079        /**
080         * The start of an element.
081         *
082         * @param namespaceURI  the namespace.
083         * @param localName  the element name.
084         * @param qName  the element name.
085         * @param atts  the attributes.
086         *
087         * @throws SAXException for errors.
088         */
089        public void startElement(String namespaceURI,
090                                 String localName,
091                                 String qName,
092                                 Attributes atts) throws SAXException {
093    
094            if (qName.equals(KEY_TAG)) {
095                clearCurrentText();
096            }
097            else {
098                throw new SAXException("Expecting <Key> but found " + qName);
099            }
100    
101        }
102    
103        /**
104         * The end of an element.
105         *
106         * @param namespaceURI  the namespace.
107         * @param localName  the element name.
108         * @param qName  the element name.
109         *
110         * @throws SAXException for errors.
111         */
112        public void endElement(String namespaceURI,
113                               String localName,
114                               String qName) throws SAXException {
115    
116            if (qName.equals(KEY_TAG)) {
117                this.itemHandler.setKey(getCurrentText());
118                this.rootHandler.popSubHandler();
119                this.rootHandler.pushSubHandler(
120                    new ValueHandler(this.rootHandler, this.itemHandler)
121                );
122            }
123            else {
124                throw new SAXException("Expecting </Key> but found " + qName);
125            }
126    
127        }
128    
129        /**
130         * Receives some (or all) of the text in the current element.
131         *
132         * @param ch  character buffer.
133         * @param start  the start index.
134         * @param length  the length of the valid character data.
135         */
136        public void characters(char[] ch, int start, int length) {
137            if (this.currentText != null) {
138                this.currentText.append(String.copyValueOf(ch, start, length));
139            }
140        }
141    
142        /**
143         * Returns the current text of the textbuffer.
144         *
145         * @return The current text.
146         */
147        protected String getCurrentText() {
148            return this.currentText.toString();
149        }
150    
151        /**
152         * Removes all text from the textbuffer at the end of a CDATA section.
153         */
154        protected void clearCurrentText() {
155            this.currentText.delete(0, this.currentText.length());
156        }
157    
158    }