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     * Dataset.java
029     * ------------
030     * (C) Copyright 2000-2005, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: Dataset.java,v 1.3.2.1 2005/10/25 21:32:29 mungady Exp $
036     *
037     * Changes (from 18-Sep-2001)
038     * --------------------------
039     * 18-Sep-2001 : Added standard header and fixed DOS encoding problem (DG);
040     * 15-Oct-2001 : Moved to a new package (com.jrefinery.data.*) (DG);
041     * 22-Oct-2001 : Changed name to Dataset.java (DG);
042     * 17-Nov-2001 : Added getLegendItemCount() and getLegendItemLabels() methods, 
043     *               created SeriesDataset interface and transferred series related
044     *               methods out (DG);
045     * 22-Jan-2002 : Reconsidered (and removed) the getLegendItemCount() and 
046     *               getLegendItemLabels() methods...leave this to client code (DG);
047     * 27-Sep-2002 : Added get/setDatasetGroup() methods (DG);
048     * 10-Jan-2003 : Updated Javadocs (DG);
049     *
050     */
051    
052    package org.jfree.data.general;
053    
054    /**
055     * The base interface for data sets.
056     * <P>
057     * All datasets are required to support the {@link DatasetChangeEvent} 
058     * mechanism by allowing listeners to register and receive notification of any 
059     * changes to the dataset.
060     * <P>
061     * In addition, all datasets must belong to one (and only one) 
062     * {@link DatasetGroup}.  The group object maintains a reader-writer lock 
063     * which provides synchronised access to the datasets in multi-threaded code.
064     */
065    public interface Dataset {
066    
067        /**
068         * Registers an object for notification of changes to the dataset.
069         *
070         * @param listener  the object to register.
071         */
072        public void addChangeListener(DatasetChangeListener listener);
073    
074        /**
075         * Deregisters an object for notification of changes to the dataset.
076         *
077         * @param listener  the object to deregister.
078         */
079        public void removeChangeListener(DatasetChangeListener listener);
080    
081        /**
082         * Returns the dataset group.
083         *
084         * @return The dataset group.
085         */
086        public DatasetGroup getGroup();
087    
088        /**
089         * Sets the dataset group.
090         *
091         * @param group  the dataset group.
092         */
093        public void setGroup(DatasetGroup group);
094    
095    }