001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2008, 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 2000-2008, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * Changes (from 18-Sep-2001)
036     * --------------------------
037     * 18-Sep-2001 : Added standard header and fixed DOS encoding problem (DG);
038     * 15-Oct-2001 : Moved to a new package (com.jrefinery.data.*) (DG);
039     * 22-Oct-2001 : Changed name to Dataset.java (DG);
040     * 17-Nov-2001 : Added getLegendItemCount() and getLegendItemLabels() methods,
041     *               created SeriesDataset interface and transferred series related
042     *               methods out (DG);
043     * 22-Jan-2002 : Reconsidered (and removed) the getLegendItemCount() and
044     *               getLegendItemLabels() methods...leave this to client code (DG);
045     * 27-Sep-2002 : Added get/setDatasetGroup() methods (DG);
046     * 10-Jan-2003 : Updated Javadocs (DG);
047     *
048     */
049    
050    package org.jfree.data.general;
051    
052    /**
053     * The base interface for data sets.
054     * <P>
055     * All datasets are required to support the {@link DatasetChangeEvent}
056     * mechanism by allowing listeners to register and receive notification of any
057     * changes to the dataset.
058     * <P>
059     * In addition, all datasets must belong to one (and only one)
060     * {@link DatasetGroup}.  The group object maintains a reader-writer lock
061     * which provides synchronised access to the datasets in multi-threaded code.
062     */
063    public interface Dataset {
064    
065        /**
066         * Registers an object for notification of changes to the dataset.
067         *
068         * @param listener  the object to register.
069         */
070        public void addChangeListener(DatasetChangeListener listener);
071    
072        /**
073         * Deregisters an object for notification of changes to the dataset.
074         *
075         * @param listener  the object to deregister.
076         */
077        public void removeChangeListener(DatasetChangeListener listener);
078    
079        /**
080         * Returns the dataset group.
081         *
082         * @return The dataset group.
083         */
084        public DatasetGroup getGroup();
085    
086        /**
087         * Sets the dataset group.
088         *
089         * @param group  the dataset group.
090         */
091        public void setGroup(DatasetGroup group);
092    
093    }