# AbstractXYZDataset.java

    /* ===========================================================
     * JFreeChart : a free chart library for the Java(tm) platform
     * ===========================================================
     *
     * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
     *
     * Project Info:  http://www.jfree.org/jfreechart/index.html
     *
     * This library is free software; you can redistribute it and/or modify it
     * under the terms of the GNU Lesser General Public License as published by
     * the Free Software Foundation; either version 2.1 of the License, or
     * (at your option) any later version.
     *
     * This library is distributed in the hope that it will be useful, but
     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
     * License for more details.
     *
     * You should have received a copy of the GNU Lesser General Public
     * License along with this library; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
     * USA.
     *
     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
     * in the United States and other countries.]
     *
     * -----------------------
     * AbstractXYZDataset.java
     * -----------------------
     * (C) Copyright 2004, 2007, by Object Refinery Limited.
     *
     * Original Author:  David Gilbert (for Object Refinery Limited).
     * Contributor(s):   -;
     *
     * Changes
     * -------
     * 05-May-2004 : Version 1 (DG);
     * 15-Jul-2004 : Switched getZ() and getZValue() (DG);
     *
     */

    package org.jfree.data.xy;

    /**
     * An base class that you can use to create new implementations of the
     * {@link XYZDataset} interface.
     */
    public abstract class AbstractXYZDataset extends AbstractXYDataset
                                             implements XYZDataset {

        /**
         * Returns the z-value (as a double primitive) for an item within a series.
         *
         * @param series  the series (zero-based index).
         * @param item  the item (zero-based index).
         *
         * @return The z-value.
         */
        public double getZValue(int series, int item) {
            double result = Double.NaN;
            Number z = getZ(series, item);
            if (z != null) {
                result = z.doubleValue();
            }
            return result;
        }

    }