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     * AbstractXYZDataset.java
029     * -----------------------
030     * (C) Copyright 2004, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited).
033     * Contributor(s):   -;
034     *
035     * $Id: AbstractXYZDataset.java,v 1.2.2.1 2005/10/25 21:36:51 mungady Exp $
036     *
037     * Changes
038     * -------
039     * 05-May-2004 : Version 1 (DG);
040     * 15-Jul-2004 : Switched getZ() and getZValue() (DG);
041     *
042     */
043    
044    package org.jfree.data.xy;
045    
046    
047    /**
048     * An base class that you can use to create new implementations of the 
049     * {@link XYZDataset} interface.
050     */
051    public abstract class AbstractXYZDataset extends AbstractXYDataset 
052                                             implements XYZDataset {
053    
054        /**
055         * Returns the z-value (as a double primitive) for an item within a series.
056         * 
057         * @param series  the series (zero-based index).
058         * @param item  the item (zero-based index).
059         * 
060         * @return The z-value.
061         */
062        public double getZValue(int series, int item) {
063            double result = Double.NaN;
064            Number z = getZ(series, item);
065            if (z != null) {
066                result = z.doubleValue();   
067            }
068            return result;   
069        }
070    
071    }