jfreechart example source code file (CategorySeriesHandler.java)

This example jfreechart source code file (CategorySeriesHandler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

categorydatasethandler, categorydatasethandler, categoryserieshandler, comparable, comparable, defaultkeyedvalues, expecting, itemhandler, itemhandler, number, sax, saxexception, series, string, string, util

The jfreechart CategorySeriesHandler.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, 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.]
 *
 * --------------------------
 * CategorySeriesHandler.java
 * --------------------------
 * (C) Copyright 2003-2008, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 23-Jan-2003 : Version 1 (DG);
 *
 */

package org.jfree.data.xml;

import java.util.Iterator;

import org.jfree.data.DefaultKeyedValues;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * A handler for reading a series for a category dataset.
 */
public class CategorySeriesHandler extends DefaultHandler
        implements DatasetTags {

    /** The root handler. */
    private RootHandler root;

    /** The series key. */
    private Comparable seriesKey;

    /** The values. */
    private DefaultKeyedValues values;

    /**
     * Creates a new item handler.
     *
     * @param root  the root handler.
     */
    public CategorySeriesHandler(RootHandler root) {
        this.root = root;
        this.values = new DefaultKeyedValues();
    }

    /**
     * Sets the series key.
     *
     * @param key  the key.
     */
    public void setSeriesKey(Comparable key) {
        this.seriesKey = key;
    }

    /**
     * Adds an item to the temporary storage for the series.
     *
     * @param key  the key.
     * @param value  the value.
     */
    public void addItem(Comparable key, final Number value) {
        this.values.addValue(key, value);
    }

    /**
     * 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(SERIES_TAG)) {
            setSeriesKey(atts.getValue("name"));
            ItemHandler subhandler = new ItemHandler(this.root, this);
            this.root.pushSubHandler(subhandler);
        }
        else if (qName.equals(ITEM_TAG)) {
            ItemHandler subhandler = new ItemHandler(this.root, this);
            this.root.pushSubHandler(subhandler);
            subhandler.startElement(namespaceURI, localName, qName, atts);
        }

        else {
            throw new SAXException(
                "Expecting <Series> or  tag...found " + qName
            );
        }
    }

    /**
     * The end of an element.
     *
     * @param namespaceURI  the namespace.
     * @param localName  the element name.
     * @param qName  the element name.
     */
    public void endElement(String namespaceURI,
                           String localName,
                           String qName) {

        if (this.root instanceof CategoryDatasetHandler) {
            CategoryDatasetHandler handler = (CategoryDatasetHandler) this.root;

            Iterator iterator = this.values.getKeys().iterator();
            while (iterator.hasNext()) {
                Comparable key = (Comparable) iterator.next();
                Number value = this.values.getValue(key);
                handler.addItem(this.seriesKey, key, value);
            }

            this.root.popSubHandler();
        }

    }

}