001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 * HistogramType.java
029 * ------------------
030 * (C) Copyright 2004-2008, by Object Refinery Limited and Contributors.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 05-Mar-2004 : Version 1 (DG);
038 *
039 */
040
041package org.jfree.data.statistics;
042
043import java.io.ObjectStreamException;
044import java.io.Serializable;
045
046/**
047 * A class for creating constants to represent the histogram type.  See Bloch's
048 * enum tip in 'Effective Java'.
049 */
050public class HistogramType implements Serializable {
051
052    /** For serialization. */
053    private static final long serialVersionUID = 2618927186251997727L;
054
055    /** Frequency histogram. */
056    public static final HistogramType FREQUENCY
057        = new HistogramType("FREQUENCY");
058
059    /** Relative frequency. */
060    public static final HistogramType RELATIVE_FREQUENCY
061        = new HistogramType("RELATIVE_FREQUENCY");
062
063    /** Scale area to one. */
064    public static final HistogramType SCALE_AREA_TO_1
065        = new HistogramType("SCALE_AREA_TO_1");
066
067    /** The type name. */
068    private String name;
069
070    /**
071     * Creates a new type.
072     *
073     * @param name  the name.
074     */
075    private HistogramType(String name) {
076        this.name = name;
077    }
078
079    /**
080     * Returns a string representing the object.
081     *
082     * @return The string.
083     */
084    public String toString() {
085        return this.name;
086    }
087
088    /**
089     * Tests this type for equality with an arbitrary object.
090     *
091     * @param obj  the object to test against.
092     *
093     * @return A boolean.
094     */
095    public boolean equals(Object obj) {
096
097        if (obj == null) {
098            return false;
099        }
100
101        if (obj == this) {
102            return true;
103        }
104
105        if (!(obj instanceof HistogramType)) {
106            return false;
107        }
108
109        HistogramType t = (HistogramType) obj;
110        if (!this.name.equals(t.name)) {
111            return false;
112        }
113
114        return true;
115
116    }
117
118    /**
119     * Returns a hash code value for the object.
120     *
121     * @return The hashcode
122     */
123    public int hashCode() {
124        return this.name.hashCode();
125    }
126
127    /**
128     * Ensures that serialization returns the unique instances.
129     *
130     * @return The object.
131     *
132     * @throws ObjectStreamException if there is a problem.
133     */
134    private Object readResolve() throws ObjectStreamException {
135        if (this.equals(HistogramType.FREQUENCY)) {
136            return HistogramType.FREQUENCY;
137        }
138        else if (this.equals(HistogramType.RELATIVE_FREQUENCY)) {
139            return HistogramType.RELATIVE_FREQUENCY;
140        }
141        else if (this.equals(HistogramType.SCALE_AREA_TO_1)) {
142            return HistogramType.SCALE_AREA_TO_1;
143        }
144        return null;
145    }
146
147}
148