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 * Layer.java
029 * ----------
030 * (C) Copyright 2003, 2004, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * $Id: Layer.java,v 1.4 2005/10/18 13:18:34 mungady Exp $
036 *
037 * Changes:
038 * --------
039 * 17-Sep-2003 (DG);
040 * 
041 */
042
043package org.jfree.ui;
044
045import java.io.ObjectStreamException;
046import java.io.Serializable;
047
048/**
049 * Used to indicate either the foreground or background layer.
050 *
051 * @author David Gilbert
052 */
053public final class Layer implements Serializable {
054
055    /** For serialization. */
056    private static final long serialVersionUID = -1470104570733183430L;
057    
058    /** Foreground. */
059    public static final Layer FOREGROUND = new Layer("Layer.FOREGROUND");
060
061    /** Background. */
062    public static final Layer BACKGROUND = new Layer("Layer.BACKGROUND");
063
064    /** The name. */
065    private String name;
066
067    /**
068     * Private constructor.
069     *
070     * @param name  the name.
071     */
072    private Layer(final String name) {
073        this.name = name;
074    }
075
076    /**
077     * Returns a string representing the object.
078     *
079     * @return The string.
080     */
081    public String toString() {
082        return this.name;
083    }
084
085    /**
086     * Returns <code>true</code> if this object is equal to the specified 
087     * object, and <code>false</code> otherwise.
088     *
089     * @param o  the other object.
090     *
091     * @return A boolean.
092     */
093    public boolean equals(final Object o) {
094
095        if (this == o) {
096            return true;
097        }
098        if (!(o instanceof Layer)) {
099            return false;
100        }
101
102        final Layer layer = (Layer) o;
103        if (!this.name.equals(layer.name)) {
104            return false;
105        }
106
107        return true;
108
109    }
110
111    /**
112     * Returns a hash code value for the object.
113     *
114     * @return the hashcode
115     */
116    public int hashCode() {
117        return this.name.hashCode();
118    }
119
120    /**
121     * Ensures that serialization returns the unique instances.
122     * 
123     * @return The object.
124     * 
125     * @throws ObjectStreamException if there is a problem.
126     */
127    private Object readResolve() throws ObjectStreamException {
128        Layer result = null;
129        if (this.equals(Layer.FOREGROUND)) {
130            result = Layer.FOREGROUND;
131        }
132        else if (this.equals(Layer.BACKGROUND)) {
133            result = Layer.BACKGROUND;
134        }
135        return result;
136    }
137    
138}
139