001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2020, 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 * [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 * TimePeriodAnchor.java
029 * ---------------------
030 * (C) Copyright 2003-2020, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.data.time;
038
039import java.io.ObjectStreamException;
040import java.io.Serializable;
041
042/**
043 * Used to indicate one of three positions in a time period:
044 * {@code START}, {@code MIDDLE} and {@code END}.
045 */
046public final class TimePeriodAnchor implements Serializable {
047
048    /** For serialization. */
049    private static final long serialVersionUID = 2011955697457548862L;
050
051    /** Start of period. */
052    public static final TimePeriodAnchor START
053        = new TimePeriodAnchor("TimePeriodAnchor.START");
054
055    /** Middle of period. */
056    public static final TimePeriodAnchor MIDDLE
057        = new TimePeriodAnchor("TimePeriodAnchor.MIDDLE");
058
059    /** End of period. */
060    public static final TimePeriodAnchor END
061        = new TimePeriodAnchor("TimePeriodAnchor.END");
062
063    /** The name. */
064    private String name;
065
066    /**
067     * Private constructor.
068     *
069     * @param name  the name.
070     */
071    private TimePeriodAnchor(String name) {
072        this.name = name;
073    }
074
075    /**
076     * Returns a string representing the object.
077     *
078     * @return The string.
079     */
080    @Override
081    public String toString() {
082        return this.name;
083    }
084
085    /**
086     * Returns {@code true} if this object is equal to the specified
087     * object, and {@code false} otherwise.
088     *
089     * @param obj  the other object.
090     *
091     * @return A boolean.
092     */
093    @Override
094    public boolean equals(Object obj) {
095
096        if (this == obj) {
097            return true;
098        }
099        if (!(obj instanceof TimePeriodAnchor)) {
100            return false;
101        }
102
103        TimePeriodAnchor position = (TimePeriodAnchor) obj;
104        if (!this.name.equals(position.name)) {
105            return false;
106        }
107
108        return true;
109    }
110
111    /**
112     * Returns a hash code value for the object.
113     *
114     * @return The hashcode
115     */
116    @Override
117    public int hashCode() {
118        return this.name.hashCode();
119    }
120
121    /**
122     * Ensures that serialization returns the unique instances.
123     *
124     * @return The object.
125     *
126     * @throws ObjectStreamException if there is a problem.
127     */
128    private Object readResolve() throws ObjectStreamException {
129        if (this.equals(TimePeriodAnchor.START)) {
130            return TimePeriodAnchor.START;
131        }
132        else if (this.equals(TimePeriodAnchor.MIDDLE)) {
133            return TimePeriodAnchor.MIDDLE;
134        }
135        else if (this.equals(TimePeriodAnchor.END)) {
136            return TimePeriodAnchor.END;
137        }
138        return null;
139    }
140
141}