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 * ValueHandler.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): Luke Quinane; 034 * 035 * $Id: ValueHandler.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 * 25-Nov-2003 : Patch to handle 'NaN' values (DG); 041 * 042 */ 043 044 package org.jfree.data.xml; 045 046 import org.xml.sax.Attributes; 047 import org.xml.sax.SAXException; 048 import org.xml.sax.helpers.DefaultHandler; 049 050 /** 051 * A handler for reading a 'Value' element. 052 */ 053 public class ValueHandler extends DefaultHandler implements DatasetTags { 054 055 /** The root handler. */ 056 private RootHandler rootHandler; 057 058 /** The item handler. */ 059 private ItemHandler itemHandler; 060 061 /** Storage for the current CDATA */ 062 private StringBuffer currentText; 063 064 /** 065 * Creates a new value handler. 066 * 067 * @param rootHandler the root handler. 068 * @param itemHandler the item handler. 069 */ 070 public ValueHandler(RootHandler rootHandler, ItemHandler itemHandler) { 071 this.rootHandler = rootHandler; 072 this.itemHandler = itemHandler; 073 this.currentText = new StringBuffer(); 074 } 075 076 /** 077 * The start of an element. 078 * 079 * @param namespaceURI the namespace. 080 * @param localName the element name. 081 * @param qName the element name. 082 * @param atts the attributes. 083 * 084 * @throws SAXException for errors. 085 */ 086 public void startElement(String namespaceURI, 087 String localName, 088 String qName, 089 Attributes atts) throws SAXException { 090 091 if (qName.equals(VALUE_TAG)) { 092 // no attributes to read 093 clearCurrentText(); 094 } 095 else { 096 throw new SAXException("Expecting <Value> but found " + qName); 097 } 098 099 } 100 101 /** 102 * The end of an element. 103 * 104 * @param namespaceURI the namespace. 105 * @param localName the element name. 106 * @param qName the element name. 107 * 108 * @throws SAXException for errors. 109 */ 110 public void endElement(String namespaceURI, 111 String localName, 112 String qName) throws SAXException { 113 114 if (qName.equals(VALUE_TAG)) { 115 Number value; 116 try { 117 value = Double.valueOf(this.currentText.toString()); 118 if (((Double) value).isNaN()) { 119 value = null; 120 } 121 } 122 catch (NumberFormatException e1) { 123 value = null; 124 } 125 this.itemHandler.setValue(value); 126 this.rootHandler.popSubHandler(); 127 } 128 else { 129 throw new SAXException("Expecting </Value> but found " + qName); 130 } 131 132 } 133 134 /** 135 * Receives some (or all) of the text in the current element. 136 * 137 * @param ch character buffer. 138 * @param start the start index. 139 * @param length the length of the valid character data. 140 */ 141 public void characters(char[] ch, int start, int length) { 142 if (this.currentText != null) { 143 this.currentText.append(String.copyValueOf(ch, start, length)); 144 } 145 } 146 147 /** 148 * Returns the current text of the textbuffer. 149 * 150 * @return The current text. 151 */ 152 protected String getCurrentText() { 153 return this.currentText.toString(); 154 } 155 156 /** 157 * Removes all text from the textbuffer at the end of a CDATA section. 158 */ 159 protected void clearCurrentText() { 160 this.currentText.delete(0, this.currentText.length()); 161 } 162 163 }