001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 * 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}