/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* -----------------
* ValueHandler.java
* -----------------
* (C) Copyright 2003-2007, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): Luke Quinane;
*
* Changes
* -------
* 23-Jan-2003 : Version 1 (DG);
* 25-Nov-2003 : Patch to handle 'NaN' values (DG);
*
*/
package org.jfree.data.xml;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* A handler for reading a 'Value' element.
*/
public class ValueHandler extends DefaultHandler implements DatasetTags {
/** The root handler. */
private RootHandler rootHandler;
/** The item handler. */
private ItemHandler itemHandler;
/** Storage for the current CDATA */
private StringBuffer currentText;
/**
* Creates a new value handler.
*
* @param rootHandler the root handler.
* @param itemHandler the item handler.
*/
public ValueHandler(RootHandler rootHandler, ItemHandler itemHandler) {
this.rootHandler = rootHandler;
this.itemHandler = itemHandler;
this.currentText = new StringBuffer();
}
/**
* The start of an element.
*
* @param namespaceURI the namespace.
* @param localName the element name.
* @param qName the element name.
* @param atts the attributes.
*
* @throws SAXException for errors.
*/
public void startElement(String namespaceURI,
String localName,
String qName,
Attributes atts) throws SAXException {
if (qName.equals(VALUE_TAG)) {
// no attributes to read
clearCurrentText();
}
else {
throw new SAXException("Expecting <Value> but found " + qName);
}
}
/**
* The end of an element.
*
* @param namespaceURI the namespace.
* @param localName the element name.
* @param qName the element name.
*
* @throws SAXException for errors.
*/
public void endElement(String namespaceURI,
String localName,
String qName) throws SAXException {
if (qName.equals(VALUE_TAG)) {
Number value;
try {
value = Double.valueOf(this.currentText.toString());
if (((Double) value).isNaN()) {
value = null;
}
}
catch (NumberFormatException e1) {
value = null;
}
this.itemHandler.setValue(value);
this.rootHandler.popSubHandler();
}
else {
throw new SAXException("Expecting </Value> but found " + qName);
}
}
/**
* Receives some (or all) of the text in the current element.
*
* @param ch character buffer.
* @param start the start index.
* @param length the length of the valid character data.
*/
public void characters(char[] ch, int start, int length) {
if (this.currentText != null) {
this.currentText.append(String.copyValueOf(ch, start, length));
}
}
/**
* Returns the current text of the textbuffer.
*
* @return The current text.
*/
protected String getCurrentText() {
return this.currentText.toString();
}
/**
* Removes all text from the textbuffer at the end of a CDATA section.
*/
protected void clearCurrentText() {
this.currentText.delete(0, this.currentText.length());
}
}
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