# DatasetRenderingOrder.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.]
     *
     * --------------------------
     * DatasetRenderingOrder.java
     * --------------------------
     * (C) Copyright 2003-2007, by Object Refinery Limited.
     *
     * Original Author:  David Gilbert (for Object Refinery Limited);
     * Contributor(s):   -;
     *
     * Changes:
     * --------
     * 02-May-2003 : Version 1 (DG);
     * 02-Jun-2004 : Changed 'STANDARD' --> 'FORWARD' (DG);
     * 21-Nov-2007 : Implemented hashCode() (DG);
     *
     */

    package org.jfree.chart.plot;

    import java.io.ObjectStreamException;
    import java.io.Serializable;

    /**
     * Defines the tokens that indicate the rendering order for datasets in a
     * {@link org.jfree.chart.plot.CategoryPlot} or an
     * {@link org.jfree.chart.plot.XYPlot}.
     */
    public final class DatasetRenderingOrder implements Serializable {

        /** For serialization. */
        private static final long serialVersionUID = -600593412366385072L;

        /**
         * Render datasets in the order 0, 1, 2, ..., N-1, where N is the number
         * of datasets.
         */
        public static final DatasetRenderingOrder FORWARD
                = new DatasetRenderingOrder("DatasetRenderingOrder.FORWARD");

        /**
         * Render datasets in the order N-1, N-2, ..., 2, 1, 0, where N is the
         * number of datasets.
         */
        public static final DatasetRenderingOrder REVERSE
                = new DatasetRenderingOrder("DatasetRenderingOrder.REVERSE");

        /** The name. */
        private String name;

        /**
         * Private constructor.
         *
         * @param name  the name.
         */
        private DatasetRenderingOrder(String name) {
            this.name = name;
        }

        /**
         * Returns a string representing the object.
         *
         * @return The string (never <code>null</code>).
         */
        public String toString() {
            return this.name;
        }

        /**
         * Returns <code>true</code> if this object is equal to the specified
         * object, and <code>false</code> otherwise.
         *
         * @param obj  the object (<code>null</code> permitted).
         *
         * @return A boolean.
         */
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (!(obj instanceof DatasetRenderingOrder)) {
                return false;
            }
            DatasetRenderingOrder order = (DatasetRenderingOrder) obj;
            if (!this.name.equals(order.toString())) {
                return false;
            }
            return true;
        }

        /**
         * Returns a hash code for this instance.
         *
         * @return A hash code.
         */
        public int hashCode() {
            return this.name.hashCode();
        }

        /**
         * Ensures that serialization returns the unique instances.
         *
         * @return The object.
         *
         * @throws ObjectStreamException if there is a problem.
         */
        private Object readResolve() throws ObjectStreamException {
            if (this.equals(DatasetRenderingOrder.FORWARD)) {
                return DatasetRenderingOrder.FORWARD;
            }
            else if (this.equals(DatasetRenderingOrder.REVERSE)) {
                return DatasetRenderingOrder.REVERSE;
            }
            return null;
        }

    }