    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2007, 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     * ValueHandler.java
    029     * -----------------
    030     * (C) Copyright 2003-2007, by Object Refinery Limited and Contributors.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   Luke Quinane;
    034     *
    035     * Changes
    036     * -------
    037     * 23-Jan-2003 : Version 1 (DG);
    038     * 25-Nov-2003 : Patch to handle 'NaN' values (DG);
    039     *
    040     */
    041
    042    package org.jfree.data.xml;
    043
    044    import org.xml.sax.Attributes;
    045    import org.xml.sax.SAXException;
    046    import org.xml.sax.helpers.DefaultHandler;
    047
    048    /**
    049     * A handler for reading a 'Value' element.
    050     */
    051    public class ValueHandler extends DefaultHandler implements DatasetTags {
    052
    053        /** The root handler. */
    054        private RootHandler rootHandler;
    055
    056        /** The item handler. */
    057        private ItemHandler itemHandler;
    058
    059        /** Storage for the current CDATA */
    060        private StringBuffer currentText;
    061
    062        /**
    063         * Creates a new value handler.
    064         *
    065         * @param rootHandler  the root handler.
    066         * @param itemHandler  the item handler.
    067         */
    068        public ValueHandler(RootHandler rootHandler, ItemHandler itemHandler) {
    069            this.rootHandler = rootHandler;
    070            this.itemHandler = itemHandler;
    071            this.currentText = new StringBuffer();
    072        }
    073
    074        /**
    075         * The start of an element.
    076         *
    077         * @param namespaceURI  the namespace.
    078         * @param localName  the element name.
    079         * @param qName  the element name.
    080         * @param atts  the attributes.
    081         *
    082         * @throws SAXException for errors.
    083         */
    084        public void startElement(String namespaceURI,
    085                                 String localName,
    086                                 String qName,
    087                                 Attributes atts) throws SAXException {
    088
    089            if (qName.equals(VALUE_TAG)) {
    090                // no attributes to read
    091                clearCurrentText();
    092            }
    093            else {
    094                throw new SAXException("Expecting <Value> but found " + qName);
    095            }
    096
    097        }
    098
    099        /**
    100         * The end of an element.
    101         *
    102         * @param namespaceURI  the namespace.
    103         * @param localName  the element name.
    104         * @param qName  the element name.
    105         *
    106         * @throws SAXException for errors.
    107         */
    108        public void endElement(String namespaceURI,
    109                               String localName,
    110                               String qName) throws SAXException {
    111
    112            if (qName.equals(VALUE_TAG)) {
    113                Number value;
    114                try {
    115                    value = Double.valueOf(this.currentText.toString());
    116                    if (((Double) value).isNaN()) {
    117                        value = null;
    118                    }
    119                }
    120                catch (NumberFormatException e1) {
    121                    value = null;
    122                }
    123                this.itemHandler.setValue(value);
    124                this.rootHandler.popSubHandler();
    125            }
    126            else {
    127                throw new SAXException("Expecting </Value> but found " + qName);
    128            }
    129
    130        }
    131
    132        /**
    133         * Receives some (or all) of the text in the current element.
    134         *
    135         * @param ch  character buffer.
    136         * @param start  the start index.
    137         * @param length  the length of the valid character data.
    138         */
    139        public void characters(char[] ch, int start, int length) {
    140            if (this.currentText != null) {
    141                this.currentText.append(String.copyValueOf(ch, start, length));
    142            }
    143        }
    144
    145        /**
    146         * Returns the current text of the textbuffer.
    147         *
    148         * @return The current text.
    149         */
    150        protected String getCurrentText() {
    151            return this.currentText.toString();
    152        }
    153
    154        /**
    155         * Removes all text from the textbuffer at the end of a CDATA section.
    156         */
    157        protected void clearCurrentText() {
    158            this.currentText.delete(0, this.currentText.length());
    159        }
    160
    161    }