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1: /* =========================================================== 2: * JFreeChart : a free chart library for the Java(tm) platform 3: * =========================================================== 4: * 5: * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors. 6: * 7: * Project Info: http://www.jfree.org/jfreechart/index.html 8: * 9: * This library is free software; you can redistribute it and/or modify it 10: * under the terms of the GNU Lesser General Public License as published by 11: * the Free Software Foundation; either version 2.1 of the License, or 12: * (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but 15: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 17: * License for more details. 18: * 19: * You should have received a copy of the GNU Lesser General Public 20: * License along with this library; if not, write to the Free Software 21: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 22: * USA. 23: * 24: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 25: * in the United States and other countries.] 26: * 27: * ----------------- 28: * ValueHandler.java 29: * ----------------- 30: * (C) Copyright 2003-2007, by Object Refinery Limited and Contributors. 31: * 32: * Original Author: David Gilbert (for Object Refinery Limited); 33: * Contributor(s): Luke Quinane; 34: * 35: * Changes 36: * ------- 37: * 23-Jan-2003 : Version 1 (DG); 38: * 25-Nov-2003 : Patch to handle 'NaN' values (DG); 39: * 40: */ 41: 42: package org.jfree.data.xml; 43: 44: import org.xml.sax.Attributes; 45: import org.xml.sax.SAXException; 46: import org.xml.sax.helpers.DefaultHandler; 47: 48: /** 49: * A handler for reading a 'Value' element. 50: */ 51: public class ValueHandler extends DefaultHandler implements DatasetTags { 52: 53: /** The root handler. */ 54: private RootHandler rootHandler; 55: 56: /** The item handler. */ 57: private ItemHandler itemHandler; 58: 59: /** Storage for the current CDATA */ 60: private StringBuffer currentText; 61: 62: /** 63: * Creates a new value handler. 64: * 65: * @param rootHandler the root handler. 66: * @param itemHandler the item handler. 67: */ 68: public ValueHandler(RootHandler rootHandler, ItemHandler itemHandler) { 69: this.rootHandler = rootHandler; 70: this.itemHandler = itemHandler; 71: this.currentText = new StringBuffer(); 72: } 73: 74: /** 75: * The start of an element. 76: * 77: * @param namespaceURI the namespace. 78: * @param localName the element name. 79: * @param qName the element name. 80: * @param atts the attributes. 81: * 82: * @throws SAXException for errors. 83: */ 84: public void startElement(String namespaceURI, 85: String localName, 86: String qName, 87: Attributes atts) throws SAXException { 88: 89: if (qName.equals(VALUE_TAG)) { 90: // no attributes to read 91: clearCurrentText(); 92: } 93: else { 94: throw new SAXException("Expecting <Value> but found " + qName); 95: } 96: 97: } 98: 99: /** 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: }