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 }