001    /* ===========================================================
002     * JFreeChart : a free chart 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/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, 2005, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: DomainOrder.java,v 1.4.2.1 2005/10/25 21:29:13 mungady Exp $
036     *
037     * Changes:
038     * --------
039     * 29-Jul-2004 : Version 1 (DG);
040     * 
041     */
042    
043    package org.jfree.data;
044    
045    import java.io.ObjectStreamException;
046    import java.io.Serializable;
047    
048    /**
049     * Used to indicate sorting order if any (ascending, descending or none).
050     */
051    public final class DomainOrder implements Serializable {
052    
053        /** For serialization. */
054        private static final long serialVersionUID = 4902774943512072627L;
055        
056        /** No order. */
057        public static final DomainOrder NONE = new DomainOrder("DomainOrder.NONE");
058    
059        /** Ascending order. */
060        public static final DomainOrder ASCENDING 
061            = new DomainOrder("DomainOrder.ASCENDING");
062    
063        /** Descending order. */
064        public static final DomainOrder DESCENDING 
065            = new DomainOrder("DomainOrder.DESCENDING");
066    
067        /** The name. */
068        private String name;
069    
070        /**
071         * Private constructor.
072         *
073         * @param name  the name.
074         */
075        private DomainOrder(String name) {
076            this.name = name;
077        }
078    
079        /**
080         * Returns a string representing the object.
081         *
082         * @return The string.
083         */
084        public String toString() {
085            return this.name;
086        }
087    
088        /**
089         * Returns <code>true</code> if this object is equal to the specified 
090         * object, and <code>false</code> otherwise.
091         *
092         * @param obj  the other object.
093         *
094         * @return A boolean.
095         */
096        public boolean equals(Object obj) {
097    
098            if (this == obj) {
099                return true;
100            }
101            if (!(obj instanceof DomainOrder)) {
102                return false;
103            }
104            DomainOrder that = (DomainOrder) obj;
105            if (!this.name.equals(that.toString())) {
106                return false;
107            }
108            return true;
109        }
110        
111        /**
112         * Returns a hash code value for the object.
113         *
114         * @return The hashcode
115         */
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    }