001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-present, by David Gilbert 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 */
028
029package org.jfree.chart.ui;
030
031import java.awt.geom.Rectangle2D;
032import java.io.ObjectStreamException;
033import java.io.Serializable;
034
035/**
036 * Used to indicate the edge of a rectangle.
037 */
038public final class RectangleEdge implements Serializable {
039
040    /** For serialization. */
041    private static final long serialVersionUID = -7400988293691093548L;
042    
043    /** Top. */
044    public static final RectangleEdge TOP 
045        = new RectangleEdge("RectangleEdge.TOP");
046
047    /** Bottom. */
048    public static final RectangleEdge BOTTOM 
049        = new RectangleEdge("RectangleEdge.BOTTOM");
050
051    /** Left. */
052    public static final RectangleEdge LEFT 
053        = new RectangleEdge("RectangleEdge.LEFT");
054
055    /** Right. */
056    public static final RectangleEdge RIGHT 
057        = new RectangleEdge("RectangleEdge.RIGHT");
058
059    /** The name. */
060    private String name;
061
062    /**
063     * Private constructor.
064     *
065     * @param name  the name.
066     */
067    private RectangleEdge(String name) {
068        this.name = name;
069    }
070
071    /**
072     * Returns a string representing the object.
073     *
074     * @return The string.
075     */
076    @Override
077    public String toString() {
078        return this.name;
079    }
080
081    /**
082     * Returns {@code true} if this object is equal to the specified 
083     * object, and {@code false} otherwise.
084     *
085     * @param o  the other object.
086     *
087     * @return A boolean.
088     */
089    @Override
090    public boolean equals(Object o) {
091
092        if (this == o) {
093            return true;
094        }
095        if (!(o instanceof RectangleEdge)) {
096            return false;
097        }
098
099        final RectangleEdge order = (RectangleEdge) o;
100        if (!this.name.equals(order.name)) {
101            return false;
102        }
103
104        return true;
105
106    }
107
108    /**
109     * Returns a hash code value for the object.
110     *
111     * @return the hashcode
112     */
113    @Override
114    public int hashCode() {
115        return this.name.hashCode();
116    }
117
118    /**
119     * Returns {@code true} if the edge is {@code TOP} or 
120     * {@code BOTTOM}, and {@code false} otherwise.
121     * 
122     * @param edge  the edge.
123     * 
124     * @return A boolean.
125     */
126    public static boolean isTopOrBottom(RectangleEdge edge) {
127        return (edge == RectangleEdge.TOP || edge == RectangleEdge.BOTTOM);    
128    }
129    
130    /**
131     * Returns {@code true} if the edge is {@code LEFT} or 
132     * {@code RIGHT}, and {@code false} otherwise.
133     * 
134     * @param edge  the edge.
135     * 
136     * @return A boolean.
137     */
138    public static boolean isLeftOrRight(RectangleEdge edge) {
139        return (edge == RectangleEdge.LEFT || edge == RectangleEdge.RIGHT);    
140    }
141
142    /**
143     * Returns the opposite edge.
144     * 
145     * @param edge  an edge.
146     * 
147     * @return The opposite edge.
148     */
149    public static RectangleEdge opposite(RectangleEdge edge) {
150        RectangleEdge result = null;
151        if (edge == RectangleEdge.TOP) {
152            result = RectangleEdge.BOTTOM;
153        }
154        else if (edge == RectangleEdge.BOTTOM) {
155            result = RectangleEdge.TOP;
156        }
157        else if (edge == RectangleEdge.LEFT) {
158            result = RectangleEdge.RIGHT;
159        }
160        else if (edge == RectangleEdge.RIGHT) {
161            result = RectangleEdge.LEFT;
162        }
163        return result;
164    }
165    
166    /**
167     * Returns the x or y coordinate of the specified edge.
168     * 
169     * @param rectangle  the rectangle.
170     * @param edge  the edge.
171     * 
172     * @return The coordinate.
173     */
174    public static double coordinate(Rectangle2D rectangle, RectangleEdge edge) {
175        double result = 0.0;
176        if (edge == RectangleEdge.TOP) {
177            result = rectangle.getMinY();
178        }
179        else if (edge == RectangleEdge.BOTTOM) {
180            result = rectangle.getMaxY();
181        }
182        else if (edge == RectangleEdge.LEFT) {
183            result = rectangle.getMinX();
184        }
185        else if (edge == RectangleEdge.RIGHT) {
186            result = rectangle.getMaxX();
187        }
188        return result;
189    }
190    
191    /**
192     * Ensures that serialization returns the unique instances.
193     * 
194     * @return The object.
195     * 
196     * @throws ObjectStreamException if there is a problem.
197     */
198    private Object readResolve() throws ObjectStreamException {
199        RectangleEdge result = null;
200        if (this.equals(RectangleEdge.TOP)) {
201            result = RectangleEdge.TOP;
202        }
203        else if (this.equals(RectangleEdge.BOTTOM)) {
204            result = RectangleEdge.BOTTOM;
205        }
206        else if (this.equals(RectangleEdge.LEFT)) {
207            result = RectangleEdge.LEFT;
208        }
209        else if (this.equals(RectangleEdge.RIGHT)) {
210            result = RectangleEdge.RIGHT;
211        }
212        return result;
213    }
214    
215}