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 * DatasetRenderingOrder.java
029 * --------------------------
030 * (C) Copyright 2003-2008, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes:
036 * --------
037 * 02-May-2003 : Version 1 (DG);
038 * 02-Jun-2004 : Changed 'STANDARD' --> 'FORWARD' (DG);
039 * 21-Nov-2007 : Implemented hashCode() (DG);
040 *
041 */
042
043package org.jfree.chart.plot;
044
045import java.io.ObjectStreamException;
046import java.io.Serializable;
047
048/**
049 * Defines the tokens that indicate the rendering order for datasets in a
050 * {@link org.jfree.chart.plot.CategoryPlot} or an
051 * {@link org.jfree.chart.plot.XYPlot}.
052 */
053public final class DatasetRenderingOrder implements Serializable {
054
055    /** For serialization. */
056    private static final long serialVersionUID = -600593412366385072L;
057
058    /**
059     * Render datasets in the order 0, 1, 2, ..., N-1, where N is the number
060     * of datasets.
061     */
062    public static final DatasetRenderingOrder FORWARD
063            = new DatasetRenderingOrder("DatasetRenderingOrder.FORWARD");
064
065    /**
066     * Render datasets in the order N-1, N-2, ..., 2, 1, 0, where N is the
067     * number of datasets.
068     */
069    public static final DatasetRenderingOrder REVERSE
070            = new DatasetRenderingOrder("DatasetRenderingOrder.REVERSE");
071
072    /** The name. */
073    private String name;
074
075    /**
076     * Private constructor.
077     *
078     * @param name  the name.
079     */
080    private DatasetRenderingOrder(String name) {
081        this.name = name;
082    }
083
084    /**
085     * Returns a string representing the object.
086     *
087     * @return The string (never <code>null</code>).
088     */
089    public String toString() {
090        return this.name;
091    }
092
093    /**
094     * Returns <code>true</code> if this object is equal to the specified
095     * object, and <code>false</code> otherwise.
096     *
097     * @param obj  the object (<code>null</code> permitted).
098     *
099     * @return A boolean.
100     */
101    public boolean equals(Object obj) {
102        if (this == obj) {
103            return true;
104        }
105        if (!(obj instanceof DatasetRenderingOrder)) {
106            return false;
107        }
108        DatasetRenderingOrder order = (DatasetRenderingOrder) obj;
109        if (!this.name.equals(order.toString())) {
110            return false;
111        }
112        return true;
113    }
114
115    /**
116     * Returns a hash code for this instance.
117     *
118     * @return A hash code.
119     */
120    public int hashCode() {
121        return this.name.hashCode();
122    }
123
124    /**
125     * Ensures that serialization returns the unique instances.
126     *
127     * @return The object.
128     *
129     * @throws ObjectStreamException if there is a problem.
130     */
131    private Object readResolve() throws ObjectStreamException {
132        if (this.equals(DatasetRenderingOrder.FORWARD)) {
133            return DatasetRenderingOrder.FORWARD;
134        }
135        else if (this.equals(DatasetRenderingOrder.REVERSE)) {
136            return DatasetRenderingOrder.REVERSE;
137        }
138        return null;
139    }
140
141}