001/* ========================================================================
002 * JCommon : a free general purpose class 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/jcommon/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 * RectangleEdge
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: RectangleEdge.java,v 1.4 2005/10/18 13:18:34 mungady Exp $
036 *
037 * Changes:
038 * --------
039 * 14-Jul-2003 (DG);
040 * 
041 */
042
043package org.jfree.ui;
044
045import java.awt.geom.Rectangle2D;
046import java.io.ObjectStreamException;
047import java.io.Serializable;
048
049/**
050 * Used to indicate the edge of a rectangle.
051 *
052 * @author David Gilbert
053 */
054public final class RectangleEdge implements Serializable {
055
056    /** For serialization. */
057    private static final long serialVersionUID = -7400988293691093548L;
058    
059    /** Top. */
060    public static final RectangleEdge TOP 
061        = new RectangleEdge("RectangleEdge.TOP");
062
063    /** Bottom. */
064    public static final RectangleEdge BOTTOM 
065        = new RectangleEdge("RectangleEdge.BOTTOM");
066
067    /** Left. */
068    public static final RectangleEdge LEFT 
069        = new RectangleEdge("RectangleEdge.LEFT");
070
071    /** Right. */
072    public static final RectangleEdge RIGHT 
073        = new RectangleEdge("RectangleEdge.RIGHT");
074
075    /** The name. */
076    private String name;
077
078    /**
079     * Private constructor.
080     *
081     * @param name  the name.
082     */
083    private RectangleEdge(final String name) {
084        this.name = name;
085    }
086
087    /**
088     * Returns a string representing the object.
089     *
090     * @return The string.
091     */
092    public String toString() {
093        return this.name;
094    }
095
096    /**
097     * Returns <code>true</code> if this object is equal to the specified 
098     * object, and <code>false</code> otherwise.
099     *
100     * @param o  the other object.
101     *
102     * @return A boolean.
103     */
104    public boolean equals(final Object o) {
105
106        if (this == o) {
107            return true;
108        }
109        if (!(o instanceof RectangleEdge)) {
110            return false;
111        }
112
113        final RectangleEdge order = (RectangleEdge) o;
114        if (!this.name.equals(order.name)) {
115            return false;
116        }
117
118        return true;
119
120    }
121
122    /**
123     * Returns a hash code value for the object.
124     *
125     * @return the hashcode
126     */
127    public int hashCode() {
128        return this.name.hashCode();
129    }
130
131    /**
132     * Returns <code>true</code> if the edge is <code>TOP</code> or 
133     * <code>BOTTOM</code>, and <code>false</code> otherwise.
134     * 
135     * @param edge  the edge.
136     * 
137     * @return A boolean.
138     */
139    public static boolean isTopOrBottom(final RectangleEdge edge) {
140        return (edge == RectangleEdge.TOP || edge == RectangleEdge.BOTTOM);    
141    }
142    
143    /**
144     * Returns <code>true</code> if the edge is <code>LEFT</code> or 
145     * <code>RIGHT</code>, and <code>false</code> otherwise.
146     * 
147     * @param edge  the edge.
148     * 
149     * @return A boolean.
150     */
151    public static boolean isLeftOrRight(final RectangleEdge edge) {
152        return (edge == RectangleEdge.LEFT || edge == RectangleEdge.RIGHT);    
153    }
154
155    /**
156     * Returns the opposite edge.
157     * 
158     * @param edge  an edge.
159     * 
160     * @return The opposite edge.
161     */
162    public static RectangleEdge opposite(final RectangleEdge edge) {
163        RectangleEdge result = null;
164        if (edge == RectangleEdge.TOP) {
165            result = RectangleEdge.BOTTOM;
166        }
167        else if (edge == RectangleEdge.BOTTOM) {
168            result = RectangleEdge.TOP;
169        }
170        else if (edge == RectangleEdge.LEFT) {
171            result = RectangleEdge.RIGHT;
172        }
173        else if (edge == RectangleEdge.RIGHT) {
174            result = RectangleEdge.LEFT;
175        }
176        return result;
177    }
178    
179    /**
180     * Returns the x or y coordinate of the specified edge.
181     * 
182     * @param rectangle  the rectangle.
183     * @param edge  the edge.
184     * 
185     * @return The coordinate.
186     */
187    public static double coordinate(final Rectangle2D rectangle, 
188                                    final RectangleEdge edge) {
189        double result = 0.0;
190        if (edge == RectangleEdge.TOP) {
191            result = rectangle.getMinY();
192        }
193        else if (edge == RectangleEdge.BOTTOM) {
194            result = rectangle.getMaxY();
195        }
196        else if (edge == RectangleEdge.LEFT) {
197            result = rectangle.getMinX();
198        }
199        else if (edge == RectangleEdge.RIGHT) {
200            result = rectangle.getMaxX();
201        }
202        return result;
203    }
204    
205    /**
206     * Ensures that serialization returns the unique instances.
207     * 
208     * @return The object.
209     * 
210     * @throws ObjectStreamException if there is a problem.
211     */
212    private Object readResolve() throws ObjectStreamException {
213        RectangleEdge result = null;
214        if (this.equals(RectangleEdge.TOP)) {
215            result = RectangleEdge.TOP;
216        }
217        else if (this.equals(RectangleEdge.BOTTOM)) {
218            result = RectangleEdge.BOTTOM;
219        }
220        else if (this.equals(RectangleEdge.LEFT)) {
221            result = RectangleEdge.LEFT;
222        }
223        else if (this.equals(RectangleEdge.RIGHT)) {
224            result = RectangleEdge.RIGHT;
225        }
226        return result;
227    }
228    
229}