    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    025 * Other names may be trademarks of their respective owners.]
    026 *
    027 * ----------------
    028 * DomainOrder.java
    029 * ----------------
    030 * (C) Copyright 2004-2008, by Object Refinery Limited.
    031 *
    032 * Original Author:  David Gilbert (for Object Refinery Limited);
    033 * Contributor(s):   -;
    034 *
    035 * Changes:
    036 * --------
    037 * 29-Jul-2004 : Version 1 (DG);
    038 *
    039 */
    040
    041package org.jfree.data;
    042
    043import java.io.ObjectStreamException;
    044import java.io.Serializable;
    045
    046/**
    047 * Used to indicate sorting order if any (ascending, descending or none).
    048 */
    049public final class DomainOrder implements Serializable {
    050
    051    /** For serialization. */
    052    private static final long serialVersionUID = 4902774943512072627L;
    053
    054    /** No order. */
    055    public static final DomainOrder NONE = new DomainOrder("DomainOrder.NONE");
    056
    057    /** Ascending order. */
    058    public static final DomainOrder ASCENDING
    059        = new DomainOrder("DomainOrder.ASCENDING");
    060
    061    /** Descending order. */
    062    public static final DomainOrder DESCENDING
    063        = new DomainOrder("DomainOrder.DESCENDING");
    064
    065    /** The name. */
    066    private String name;
    067
    068    /**
    069     * Private constructor.
    070     *
    071     * @param name  the name.
    072     */
    073    private DomainOrder(String name) {
    074        this.name = name;
    075    }
    076
    077    /**
    078     * Returns a string representing the object.
    079     *
    080     * @return The string.
    081     */
    082    public String toString() {
    083        return this.name;
    084    }
    085
    086    /**
    087     * Returns <code>true</code> if this object is equal to the specified
    088     * object, and <code>false</code> otherwise.
    089     *
    090     * @param obj  the other object.
    091     *
    092     * @return A boolean.
    093     */
    094    public boolean equals(Object obj) {
    095
    096        if (this == obj) {
    097            return true;
    098        }
    099        if (!(obj instanceof DomainOrder)) {
    100            return false;
    101        }
    102        DomainOrder that = (DomainOrder) obj;
    103        if (!this.name.equals(that.toString())) {
    104            return false;
    105        }
    106        return true;
    107    }
    108
    109    /**
    110     * Returns a hash code value for the object.
    111     *
    112     * @return The hashcode
    113     */
    114    public int hashCode() {
    115        return this.name.hashCode();
    116    }
    117
    118    /**
    119     * Ensures that serialization returns the unique instances.
    120     *
    121     * @return The object.
    122     *
    123     * @throws ObjectStreamException if there is a problem.
    124     */
    125    private Object readResolve() throws ObjectStreamException {
    126        if (this.equals(DomainOrder.ASCENDING)) {
    127            return DomainOrder.ASCENDING;
    128        }
    129        else if (this.equals(DomainOrder.DESCENDING)) {
    130            return DomainOrder.DESCENDING;
    131        }
    132        else if (this.equals(DomainOrder.NONE)) {
    133            return DomainOrder.NONE;
    134        }
    135        return null;
    136    }
    137
    138}