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     * AxisLocation.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: AxisLocation.java,v 1.4.2.1 2005/10/25 20:37:34 mungady Exp $
036     *
037     * Changes:
038     * --------
039     * 02-May-2003 : Version 1 (DG);
040     * 03-Jul-2003 : Added isTopOrBottom() and isLeftOrRight() methods (DG);
041     * 13-Aug-2003 : Fixed readResolve() bug (id=788202) (DG);
042     * 24-Mar-2004 : Added getOpposite() method (DG);
043     *
044     */
045    
046    package org.jfree.chart.axis;
047    
048    import java.io.ObjectStreamException;
049    import java.io.Serializable;
050    
051    /**
052     * Used to indicate the location of an axis on a 2D plot, prior to knowing the 
053     * orientation of the plot.
054     */
055    public final class AxisLocation implements Serializable {
056    
057        /** For serialization. */
058        private static final long serialVersionUID = -3276922179323563410L;
059        
060        /** Axis at the top or left. */
061        public static final AxisLocation TOP_OR_LEFT = new AxisLocation(
062            "AxisLocation.TOP_OR_LEFT"
063        );
064    
065        /** Axis at the top or right. */
066        public static final AxisLocation TOP_OR_RIGHT = new AxisLocation(
067            "AxisLocation.TOP_OR_RIGHT"
068        );
069        
070        /** Axis at the bottom or left. */
071        public static final AxisLocation BOTTOM_OR_LEFT = new AxisLocation(
072            "AxisLocation.BOTTOM_OR_LEFT"
073        );
074            
075        /** Axis at the bottom or right. */
076        public static final AxisLocation BOTTOM_OR_RIGHT = new AxisLocation(
077            "AxisLocation.BOTTOM_OR_RIGHT"
078        );
079        
080        /** The name. */
081        private String name;
082    
083        /**
084         * Private constructor.
085         *
086         * @param name  the name.
087         */
088        private AxisLocation(String name) {
089            this.name = name;
090        }
091    
092        /**
093         * Returns a string representing the object.
094         *
095         * @return The string.
096         */
097        public String toString() {
098            return this.name;
099        }
100    
101        /**
102         * Returns <code>true</code> if this object is equal to the specified 
103         * object, and <code>false</code> otherwise.
104         *
105         * @param obj  the other object (<code>null</code> permitted).
106         *
107         * @return A boolean.
108         */
109        public boolean equals(Object obj) {
110    
111            if (this == obj) {
112                return true;
113            }
114            if (!(obj instanceof AxisLocation)) {
115                return false;
116            }
117            AxisLocation location = (AxisLocation) obj;
118            if (!this.name.equals(location.toString())) {
119                return false;
120            }
121            return true;
122    
123        }
124        
125        /**
126         * Returns the location that is opposite to the supplied location.
127         * 
128         * @param location  the location (<code>null</code> not permitted).
129         * 
130         * @return The opposite location.
131         */
132        public static AxisLocation getOpposite(AxisLocation location) {
133            if (location == null) {
134                throw new IllegalArgumentException("Null 'location' argument.");   
135            }
136            AxisLocation result = null;
137            if (location == AxisLocation.TOP_OR_LEFT) {
138                result = AxisLocation.BOTTOM_OR_RIGHT;   
139            }
140            else if (location == AxisLocation.TOP_OR_RIGHT) {
141                result = AxisLocation.BOTTOM_OR_LEFT;   
142            }
143            else if (location == AxisLocation.BOTTOM_OR_LEFT) {
144                result = AxisLocation.TOP_OR_RIGHT;   
145            }
146            else if (location == AxisLocation.BOTTOM_OR_RIGHT) {
147                result = AxisLocation.TOP_OR_LEFT;   
148            }
149            else {
150                throw new IllegalStateException("AxisLocation not recognised.");   
151            }
152            return result;
153        }
154            
155        /**
156         * Ensures that serialization returns the unique instances.
157         * 
158         * @return The object.
159         * 
160         * @throws ObjectStreamException if there is a problem.
161         */
162        private Object readResolve() throws ObjectStreamException {
163            if (this.equals(AxisLocation.TOP_OR_RIGHT)) {
164                return AxisLocation.TOP_OR_RIGHT;
165            }
166            else if (this.equals(AxisLocation.BOTTOM_OR_RIGHT)) {
167                return AxisLocation.BOTTOM_OR_RIGHT;
168            }    
169            else if (this.equals(AxisLocation.TOP_OR_LEFT)) {
170                return AxisLocation.TOP_OR_LEFT;
171            }    
172            else if (this.equals(AxisLocation.BOTTOM_OR_LEFT)) {
173                return AxisLocation.BOTTOM_OR_LEFT;
174            }
175            return null;
176        }
177        
178    }