    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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 * [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 2000-2008, by Object Refinery Limited.
    031 *
    032 * Original Author:  David Gilbert (for Object Refinery Limited);
    033 * Contributor(s):   -;
    034 *
    035 * Changes (from 24-Aug-2001)
    036 * --------------------------
    037 * 24-Aug-2001 : Added standard source header. Fixed DOS encoding problem (DG);
    038 * 15-Oct-2001 : Move to new package (com.jrefinery.data.*) (DG);
    039 * 22-Oct-2001 : Renamed DataSource.java --> Dataset.java etc. (DG);
    040 * 11-Jun-2002 : Separated the event source from the dataset to cover the case
    041 *               where the dataset is changed to null in the Plot class.
    042 *               Updated Javadocs (DG);
    043 * 04-Oct-2002 : Fixed errors reported by Checkstyle (DG);
    044 * 05-Oct-2004 : Minor Javadoc updates (DG);
    045 *
    046 */
    047
    048package org.jfree.data.general;
    049
    050/**
    051 * A change event that encapsulates information about a change to a dataset.
    052 */
    053public class DatasetChangeEvent extends java.util.EventObject {
    054
    055    /**
    056     * The dataset that generated the change event.
    057     */
    058    private Dataset dataset;
    059
    060    /**
    061     * Constructs a new event.  The source is either the dataset or the
    062     * {@link org.jfree.chart.plot.Plot} class.  The dataset can be
    063     * <code>null</code> (in this case the source will be the
    064     * {@link org.jfree.chart.plot.Plot} class).
    065     *
    066     * @param source  the source of the event.
    067     * @param dataset  the dataset that generated the event (<code>null</code>
    068     *                 permitted).
    069     */
    070    public DatasetChangeEvent(Object source, Dataset dataset) {
    071        super(source);
    072        this.dataset = dataset;
    073    }
    074
    075    /**
    076     * Returns the dataset that generated the event.  Note that the dataset
    077     * may be <code>null</code> since adding a <code>null</code> dataset to a
    078     * plot will generated a change event.
    079     *
    080     * @return The dataset (possibly <code>null</code>).
    081     */
    082    public Dataset getDataset() {
    083        return this.dataset;
    084    }
    085
    086}