001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2013, 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    @Override
083    public String toString() {
084        return this.name;
085    }
086
087    /**
088     * Returns <code>true</code> if this object is equal to the specified
089     * object, and <code>false</code> otherwise.
090     *
091     * @param obj  the other object.
092     *
093     * @return A boolean.
094     */
095    @Override
096    public boolean equals(Object obj) {
097        if (this == obj) {
098            return true;
099        }
100        if (!(obj instanceof DomainOrder)) {
101            return false;
102        }
103        DomainOrder that = (DomainOrder) obj;
104        if (!this.name.equals(that.toString())) {
105            return false;
106        }
107        return true;
108    }
109
110    /**
111     * Returns a hash code value for the object.
112     *
113     * @return The hashcode
114     */
115    @Override
116    public int hashCode() {
117        return this.name.hashCode();
118    }
119
120    /**
121     * Ensures that serialization returns the unique instances.
122     *
123     * @return The object.
124     *
125     * @throws ObjectStreamException if there is a problem.
126     */
127    private Object readResolve() throws ObjectStreamException {
128        if (this.equals(DomainOrder.ASCENDING)) {
129            return DomainOrder.ASCENDING;
130        }
131        else if (this.equals(DomainOrder.DESCENDING)) {
132            return DomainOrder.DESCENDING;
133        }
134        else if (this.equals(DomainOrder.NONE)) {
135            return DomainOrder.NONE;
136        }
137        return null;
138    }
139
140}