001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2007, 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 2003-2007, by Object Refinery Limited and Contributors.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   Nick Guenther;
034     *
035     * $Id: AxisLocation.java,v 1.4.2.3 2007/03/22 10:59:34 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 static getOpposite() method (DG);
043     * ------------- JFREECHART 1.0.x ---------------------------------------------
044     * 22-Mar-2007 : Added getOpposite() method, suggested by Nick Guenther (DG);
045     *
046     */
047    
048    package org.jfree.chart.axis;
049    
050    import java.io.ObjectStreamException;
051    import java.io.Serializable;
052    
053    /**
054     * Used to indicate the location of an axis on a 2D plot, prior to knowing the 
055     * orientation of the plot.
056     */
057    public final class AxisLocation implements Serializable {
058    
059        /** For serialization. */
060        private static final long serialVersionUID = -3276922179323563410L;
061        
062        /** Axis at the top or left. */
063        public static final AxisLocation TOP_OR_LEFT = new AxisLocation(
064                "AxisLocation.TOP_OR_LEFT");
065    
066        /** Axis at the top or right. */
067        public static final AxisLocation TOP_OR_RIGHT = new AxisLocation(
068                "AxisLocation.TOP_OR_RIGHT");
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        /** Axis at the bottom or right. */
075        public static final AxisLocation BOTTOM_OR_RIGHT = new AxisLocation(
076                "AxisLocation.BOTTOM_OR_RIGHT");
077        
078        /** The name. */
079        private String name;
080    
081        /**
082         * Private constructor.
083         *
084         * @param name  the name.
085         */
086        private AxisLocation(String name) {
087            this.name = name;
088        }
089    
090        /**
091         * Returns the location that is opposite to this location.
092         *
093         * @return The opposite location.
094         * 
095         * @since 1.0.5
096         */
097        public AxisLocation getOpposite() {
098            return getOpposite(this);
099        }
100        
101        /**
102         * Returns a string representing the object.
103         *
104         * @return The string.
105         */
106        public String toString() {
107            return this.name;
108        }
109    
110        /**
111         * Returns <code>true</code> if this object is equal to the specified 
112         * object, and <code>false</code> otherwise.
113         *
114         * @param obj  the other object (<code>null</code> permitted).
115         *
116         * @return A boolean.
117         */
118        public boolean equals(Object obj) {
119    
120            if (this == obj) {
121                return true;
122            }
123            if (!(obj instanceof AxisLocation)) {
124                return false;
125            }
126            AxisLocation location = (AxisLocation) obj;
127            if (!this.name.equals(location.toString())) {
128                return false;
129            }
130            return true;
131    
132        }
133        
134        /**
135         * Returns the location that is opposite to the supplied location.
136         * 
137         * @param location  the location (<code>null</code> not permitted).
138         * 
139         * @return The opposite location.
140         */
141        public static AxisLocation getOpposite(AxisLocation location) {
142            if (location == null) {
143                throw new IllegalArgumentException("Null 'location' argument.");   
144            }
145            AxisLocation result = null;
146            if (location == AxisLocation.TOP_OR_LEFT) {
147                result = AxisLocation.BOTTOM_OR_RIGHT;   
148            }
149            else if (location == AxisLocation.TOP_OR_RIGHT) {
150                result = AxisLocation.BOTTOM_OR_LEFT;   
151            }
152            else if (location == AxisLocation.BOTTOM_OR_LEFT) {
153                result = AxisLocation.TOP_OR_RIGHT;   
154            }
155            else if (location == AxisLocation.BOTTOM_OR_RIGHT) {
156                result = AxisLocation.TOP_OR_LEFT;   
157            }
158            else {
159                throw new IllegalStateException("AxisLocation not recognised.");   
160            }
161            return result;
162        }
163            
164        /**
165         * Ensures that serialization returns the unique instances.
166         * 
167         * @return The object.
168         * 
169         * @throws ObjectStreamException if there is a problem.
170         */
171        private Object readResolve() throws ObjectStreamException {
172            if (this.equals(AxisLocation.TOP_OR_RIGHT)) {
173                return AxisLocation.TOP_OR_RIGHT;
174            }
175            else if (this.equals(AxisLocation.BOTTOM_OR_RIGHT)) {
176                return AxisLocation.BOTTOM_OR_RIGHT;
177            }    
178            else if (this.equals(AxisLocation.TOP_OR_LEFT)) {
179                return AxisLocation.TOP_OR_LEFT;
180            }    
181            else if (this.equals(AxisLocation.BOTTOM_OR_LEFT)) {
182                return AxisLocation.BOTTOM_OR_LEFT;
183            }
184            return null;
185        }
186        
187    }