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 * AxisLocation.java
029 * -----------------
030 * (C) Copyright 2003-present, by David Gilbert and Contributors.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   Nick Guenther;
034 *
035 */
036
037package org.jfree.chart.axis;
038
039import java.io.ObjectStreamException;
040import java.io.Serializable;
041import org.jfree.chart.util.Args;
042
043/**
044 * Used to indicate the location of an axis on a 2D plot, prior to knowing the
045 * orientation of the plot.
046 */
047public final class AxisLocation implements Serializable {
048
049    /** For serialization. */
050    private static final long serialVersionUID = -3276922179323563410L;
051
052    /** Axis at the top or left. */
053    public static final AxisLocation TOP_OR_LEFT = new AxisLocation(
054            "AxisLocation.TOP_OR_LEFT");
055
056    /** Axis at the top or right. */
057    public static final AxisLocation TOP_OR_RIGHT = new AxisLocation(
058            "AxisLocation.TOP_OR_RIGHT");
059
060    /** Axis at the bottom or left. */
061    public static final AxisLocation BOTTOM_OR_LEFT = new AxisLocation(
062            "AxisLocation.BOTTOM_OR_LEFT");
063
064    /** Axis at the bottom or right. */
065    public static final AxisLocation BOTTOM_OR_RIGHT = new AxisLocation(
066            "AxisLocation.BOTTOM_OR_RIGHT");
067
068    /** The name. */
069    private final String name;
070
071    /**
072     * Private constructor.
073     *
074     * @param name  the name.
075     */
076    private AxisLocation(String name) {
077        this.name = name;
078    }
079
080    /**
081     * Returns the location that is opposite to this location.
082     *
083     * @return The opposite location.
084     */
085    public AxisLocation getOpposite() {
086        return getOpposite(this);
087    }
088
089    /**
090     * Returns a string representing the object.
091     *
092     * @return The string.
093     */
094    @Override
095    public String toString() {
096        return this.name;
097    }
098
099    /**
100     * Returns {@code true} if this object is equal to the specified
101     * object, and {@code false} otherwise.
102     *
103     * @param obj  the other object ({@code null} permitted).
104     *
105     * @return A boolean.
106     */
107    @Override
108    public boolean equals(Object obj) {
109        if (this == obj) {
110            return true;
111        }
112        if (!(obj instanceof AxisLocation)) {
113            return false;
114        }
115        AxisLocation location = (AxisLocation) obj;
116        if (!this.name.equals(location.toString())) {
117            return false;
118        }
119        return true;
120    }
121
122    /**
123     * Returns a hash code for this instance.
124     * 
125     * @return A hash code.
126     */
127    @Override
128    public int hashCode() {
129        int hash = 5;
130        hash = 83 * hash + this.name.hashCode();
131        return hash;
132    }
133
134    /**
135     * Returns the location that is opposite to the supplied location.
136     *
137     * @param location  the location ({@code null} not permitted).
138     *
139     * @return The opposite location.
140     */
141    public static AxisLocation getOpposite(AxisLocation location) {
142        Args.nullNotPermitted(location, "location");
143        AxisLocation result = null;
144        if (location == AxisLocation.TOP_OR_LEFT) {
145            result = AxisLocation.BOTTOM_OR_RIGHT;
146        }
147        else if (location == AxisLocation.TOP_OR_RIGHT) {
148            result = AxisLocation.BOTTOM_OR_LEFT;
149        }
150        else if (location == AxisLocation.BOTTOM_OR_LEFT) {
151            result = AxisLocation.TOP_OR_RIGHT;
152        }
153        else if (location == AxisLocation.BOTTOM_OR_RIGHT) {
154            result = AxisLocation.TOP_OR_LEFT;
155        }
156        else {
157            throw new IllegalStateException("AxisLocation not recognised.");
158        }
159        return result;
160    }
161
162    /**
163     * Ensures that serialization returns the unique instances.
164     *
165     * @return The object.
166     *
167     * @throws ObjectStreamException if there is a problem.
168     */
169    private Object readResolve() throws ObjectStreamException {
170        if (this.equals(AxisLocation.TOP_OR_RIGHT)) {
171            return AxisLocation.TOP_OR_RIGHT;
172        }
173        else if (this.equals(AxisLocation.BOTTOM_OR_RIGHT)) {
174            return AxisLocation.BOTTOM_OR_RIGHT;
175        }
176        else if (this.equals(AxisLocation.TOP_OR_LEFT)) {
177            return AxisLocation.TOP_OR_LEFT;
178        }
179        else if (this.equals(AxisLocation.BOTTOM_OR_LEFT)) {
180            return AxisLocation.BOTTOM_OR_LEFT;
181        }
182        return null;
183    }
184
185}