    001    /* ========================================================================
    002     * JCommon : a free general purpose class 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/jcommon/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     * SortOrder.java
    029     * --------------
    030     * (C) Copyright 2003, 2004, by Object Refinery Limited.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   -;
    034     *
    035     * $Id: SortOrder.java,v 1.6 2005/10/18 13:24:19 mungady Exp $
    036     *
    037     * Changes:
    038     * --------
    039     * 05-Mar-2003 : Version 1 (DG);
    040     * 13-Mar-2003 : Implemented Serializable (DG);
    041     * 27-Aug-2003 : Moved from JFreeChart --> JCommon (DG);
    042     * 29-Jul-2004 : Fixed error in readResolve() method (DG);
    043     *
    044     */
    045
    046    package org.jfree.util;
    047
    048    import java.io.ObjectStreamException;
    049    import java.io.Serializable;
    050
    051    /**
    052     * Defines tokens used to indicate sorting order (ascending or descending).
    053     *
    054     * @author David Gilbert
    055     */
    056    public final class SortOrder implements Serializable {
    057
    058        /** For serialization. */
    059        private static final long serialVersionUID = -2124469847758108312L;
    060
    061        /** Ascending order. */
    062        public static final SortOrder ASCENDING
    063            = new SortOrder("SortOrder.ASCENDING");
    064
    065        /** Descending order. */
    066        public static final SortOrder DESCENDING
    067            = new SortOrder("SortOrder.DESCENDING");
    068
    069        /** The name. */
    070        private String name;
    071
    072        /**
    073         * Private constructor.
    074         *
    075         * @param name  the name.
    076         */
    077        private SortOrder(final String name) {
    078            this.name = name;
    079        }
    080
    081        /**
    082         * Returns a string representing the object.
    083         *
    084         * @return The string.
    085         */
    086        public String toString() {
    087            return this.name;
    088        }
    089
    090        /**
    091         * Returns <code>true</code> if this object is equal to the specified
    092         * object, and <code>false</code> otherwise.
    093         *
    094         * @param obj  the other object.
    095         *
    096         * @return A boolean.
    097         */
    098        public boolean equals(final Object obj) {
    099
    100            if (this == obj) {
    101                return true;
    102            }
    103            if (!(obj instanceof SortOrder)) {
    104                return false;
    105            }
    106
    107            final SortOrder that = (SortOrder) obj;
    108            if (!this.name.equals(that.toString())) {
    109                return false;
    110            }
    111
    112            return true;
    113        }
    114
    115        /**
    116         * Returns a hash code value for the object.
    117         *
    118         * @return The hashcode
    119         */
    120        public int hashCode() {
    121            return this.name.hashCode();
    122        }
    123
    124        /**
    125         * Ensures that serialization returns the unique instances.
    126         *
    127         * @return The object.
    128         *
    129         * @throws ObjectStreamException if there is a problem.
    130         */
    131        private Object readResolve() throws ObjectStreamException {
    132            if (this.equals(SortOrder.ASCENDING)) {
    133                return SortOrder.ASCENDING;
    134            }
    135            else if (this.equals(SortOrder.DESCENDING)) {
    136                return SortOrder.DESCENDING;
    137            }
    138            return null;
    139        }
    140    }