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     * CategoryAnchor.java
029     * -------------------
030     * (C) Copyright 2003-2005, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: CategoryAnchor.java,v 1.4.2.1 2005/10/25 20:37:34 mungady Exp $
036     *
037     * Changes:
038     * --------
039     * 04-Jul-2003 : Version 1 (DG);
040     *
041     */
042    
043    package org.jfree.chart.axis;
044    
045    import java.io.ObjectStreamException;
046    import java.io.Serializable;
047    
048    /**
049     * Used to indicate one of three positions within a category: 
050     * <code>START</code>, <code>MIDDLE</code> and <code>END</code>.
051     */
052    public final class CategoryAnchor implements Serializable {
053    
054        /** For serialization. */
055        private static final long serialVersionUID = -2604142742210173810L;
056        
057        /** Start of period. */
058        public static final CategoryAnchor START 
059            = new CategoryAnchor("CategoryAnchor.START");
060    
061        /** Middle of period. */
062        public static final CategoryAnchor MIDDLE 
063            = new CategoryAnchor("CategoryAnchor.MIDDLE");
064    
065        /** End of period. */
066        public static final CategoryAnchor END 
067            = new CategoryAnchor("CategoryAnchor.END");
068    
069        /** The name. */
070        private String name;
071    
072        /**
073         * Private constructor.
074         *
075         * @param name  the name.
076         */
077        private CategoryAnchor(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(Object obj) {
099    
100            if (this == obj) {
101                return true;
102            }
103            if (!(obj instanceof CategoryAnchor)) {
104                return false;
105            }
106            CategoryAnchor position = (CategoryAnchor) obj;
107            if (!this.name.equals(position.toString())) {
108                return false;
109            }
110            return true;
111    
112        }
113        
114        /**
115         * Ensures that serialization returns the unique instances.
116         * 
117         * @return The object.
118         * 
119         * @throws ObjectStreamException if there is a problem.
120         */
121        private Object readResolve() throws ObjectStreamException {
122            if (this.equals(CategoryAnchor.START)) {
123                return CategoryAnchor.START;
124            }
125            else if (this.equals(CategoryAnchor.MIDDLE)) {
126                return CategoryAnchor.MIDDLE;
127            }    
128            else if (this.equals(CategoryAnchor.END)) {
129                return CategoryAnchor.END;
130            }    
131            return null;
132        }
133    
134    }