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 }