001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-present, by David Gilbert 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 * DatasetRenderingOrder.java
029 * --------------------------
030 * (C) Copyright 2003-present, by David Gilbert.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.chart.plot;
038
039import java.io.ObjectStreamException;
040import java.io.Serializable;
041
042/**
043 * Defines the tokens that indicate the rendering order for datasets in a
044 * {@link org.jfree.chart.plot.CategoryPlot} or an
045 * {@link org.jfree.chart.plot.XYPlot}.
046 */
047public final class DatasetRenderingOrder implements Serializable {
048
049    /** For serialization. */
050    private static final long serialVersionUID = -600593412366385072L;
051
052    /**
053     * Render datasets in the order 0, 1, 2, ..., N-1, where N is the number
054     * of datasets.
055     */
056    public static final DatasetRenderingOrder FORWARD
057            = new DatasetRenderingOrder("DatasetRenderingOrder.FORWARD");
058
059    /**
060     * Render datasets in the order N-1, N-2, ..., 2, 1, 0, where N is the
061     * number of datasets.
062     */
063    public static final DatasetRenderingOrder REVERSE
064            = new DatasetRenderingOrder("DatasetRenderingOrder.REVERSE");
065
066    /** The name. */
067    private final String name;
068
069    /**
070     * Private constructor.
071     *
072     * @param name  the name.
073     */
074    private DatasetRenderingOrder(String name) {
075        this.name = name;
076    }
077
078    /**
079     * Returns a string representing the object.
080     *
081     * @return The string (never {@code null}).
082     */
083    @Override
084    public String toString() {
085        return this.name;
086    }
087
088    /**
089     * Returns {@code true} if this object is equal to the specified
090     * object, and {@code false} otherwise.
091     *
092     * @param obj  the object ({@code null} permitted).
093     *
094     * @return A boolean.
095     */
096    @Override
097    public boolean equals(Object obj) {
098        if (this == obj) {
099            return true;
100        }
101        if (!(obj instanceof DatasetRenderingOrder)) {
102            return false;
103        }
104        DatasetRenderingOrder order = (DatasetRenderingOrder) obj;
105        if (!this.name.equals(order.toString())) {
106            return false;
107        }
108        return true;
109    }
110
111    /**
112     * Returns a hash code for this instance.
113     *
114     * @return A hash code.
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(DatasetRenderingOrder.FORWARD)) {
130            return DatasetRenderingOrder.FORWARD;
131        }
132        else if (this.equals(DatasetRenderingOrder.REVERSE)) {
133            return DatasetRenderingOrder.REVERSE;
134        }
135        return null;
136    }
137
138}