001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-present, by David Gilbert 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 * -----------------------
028 * DatasetChangeEvent.java
029 * -----------------------
030 * (C) Copyright 2000-present, by David Gilbert.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.data.general;
038
039/**
040 * A change event that encapsulates information about a change to a dataset.
041 */
042public class DatasetChangeEvent extends java.util.EventObject {
043
044    /**
045     * The dataset that generated the change event.
046     */
047    private Dataset dataset;
048
049    /**
050     * Constructs a new event.  The source is either the dataset or the
051     * {@link org.jfree.chart.plot.Plot} class.  The dataset can be
052     * {@code null} (in this case the source will be the
053     * {@link org.jfree.chart.plot.Plot} class).
054     *
055     * @param source  the source of the event.
056     * @param dataset  the dataset that generated the event ({@code null}
057     *                 permitted).
058     */
059    public DatasetChangeEvent(Object source, Dataset dataset) {
060        super(source);
061        this.dataset = dataset;
062    }
063
064    /**
065     * Returns the dataset that generated the event.  Note that the dataset
066     * may be {@code null} since adding a {@code null} dataset to a
067     * plot will generated a change event.
068     *
069     * @return The dataset (possibly {@code null}).
070     */
071    public Dataset getDataset() {
072        return this.dataset;
073    }
074
075}