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 * AxisLocation.java
029 * -----------------
030 * (C) Copyright 2003-2008, by Object Refinery Limited and Contributors.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   Nick Guenther;
034 *
035 * Changes:
036 * --------
037 * 02-May-2003 : Version 1 (DG);
038 * 03-Jul-2003 : Added isTopOrBottom() and isLeftOrRight() methods (DG);
039 * 13-Aug-2003 : Fixed readResolve() bug (id=788202) (DG);
040 * 24-Mar-2004 : Added static getOpposite() method (DG);
041 * ------------- JFREECHART 1.0.x ---------------------------------------------
042 * 22-Mar-2007 : Added getOpposite() method, suggested by Nick Guenther (DG);
043 *
044 */
045
046package org.jfree.chart.axis;
047
048import java.io.ObjectStreamException;
049import java.io.Serializable;
050
051/**
052 * Used to indicate the location of an axis on a 2D plot, prior to knowing the
053 * orientation of the plot.
054 */
055public final class AxisLocation implements Serializable {
056
057    /** For serialization. */
058    private static final long serialVersionUID = -3276922179323563410L;
059
060    /** Axis at the top or left. */
061    public static final AxisLocation TOP_OR_LEFT = new AxisLocation(
062            "AxisLocation.TOP_OR_LEFT");
063
064    /** Axis at the top or right. */
065    public static final AxisLocation TOP_OR_RIGHT = new AxisLocation(
066            "AxisLocation.TOP_OR_RIGHT");
067
068    /** Axis at the bottom or left. */
069    public static final AxisLocation BOTTOM_OR_LEFT = new AxisLocation(
070            "AxisLocation.BOTTOM_OR_LEFT");
071
072    /** Axis at the bottom or right. */
073    public static final AxisLocation BOTTOM_OR_RIGHT = new AxisLocation(
074            "AxisLocation.BOTTOM_OR_RIGHT");
075
076    /** The name. */
077    private String name;
078
079    /**
080     * Private constructor.
081     *
082     * @param name  the name.
083     */
084    private AxisLocation(String name) {
085        this.name = name;
086    }
087
088    /**
089     * Returns the location that is opposite to this location.
090     *
091     * @return The opposite location.
092     *
093     * @since 1.0.5
094     */
095    public AxisLocation getOpposite() {
096        return getOpposite(this);
097    }
098
099    /**
100     * Returns a string representing the object.
101     *
102     * @return The string.
103     */
104    public String toString() {
105        return this.name;
106    }
107
108    /**
109     * Returns <code>true</code> if this object is equal to the specified
110     * object, and <code>false</code> otherwise.
111     *
112     * @param obj  the other object (<code>null</code> permitted).
113     *
114     * @return A boolean.
115     */
116    public boolean equals(Object obj) {
117
118        if (this == obj) {
119            return true;
120        }
121        if (!(obj instanceof AxisLocation)) {
122            return false;
123        }
124        AxisLocation location = (AxisLocation) obj;
125        if (!this.name.equals(location.toString())) {
126            return false;
127        }
128        return true;
129
130    }
131
132    /**
133     * Returns the location that is opposite to the supplied location.
134     *
135     * @param location  the location (<code>null</code> not permitted).
136     *
137     * @return The opposite location.
138     */
139    public static AxisLocation getOpposite(AxisLocation location) {
140        if (location == null) {
141            throw new IllegalArgumentException("Null 'location' argument.");
142        }
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}