001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2005, 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     * TickUnit.java
029     * -------------
030     * (C) Copyright 2001-2005, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: TickUnit.java,v 1.3.2.2 2005/10/25 20:37:34 mungady Exp $
036     *
037     * Changes (from 19-Dec-2001)
038     * --------------------------
039     * 19-Dec-2001 : Added standard header (DG);
040     * 01-May-2002 : Changed the unit size from Number to double (DG);
041     * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
042     * 08-Nov-2002 : Moved to new package com.jrefinery.chart.axis (DG);
043     * 26-Mar-2003 : Implemented Serializable (DG);
044     * 05-Sep-2005 : Implemented hashCode(), thanks to Thomas Morgner (DG);
045     *
046     */
047    
048    package org.jfree.chart.axis;
049    
050    import java.io.Serializable;
051    
052    /**
053     * Base class representing a tick unit.  This determines the spacing of the
054     * tick marks on an axis.
055     * <P>
056     * This class (and any subclasses) should be immutable, the reason being that
057     * ORDERED collections of tick units are maintained and if one instance can be
058     * changed, it may destroy the order of the collection that it belongs to.
059     * In addition, if the implementations are immutable, they can belong to
060     * multiple collections.
061     *
062     * @see ValueAxis
063     */
064    public abstract class TickUnit implements Comparable, Serializable {
065    
066        /** For serialization. */
067        private static final long serialVersionUID = 510179855057013974L;
068        
069        /** The size of the tick unit. */
070        private double size;
071    
072        /**
073         * Constructs a new tick unit.
074         *
075         * @param size  the tick unit size.
076         */
077        public TickUnit(double size) {
078            this.size = size;
079        }
080    
081        /**
082         * Returns the size of the tick unit.
083         *
084         * @return The size of the tick unit.
085         */
086        public double getSize() {
087            return this.size;
088        }
089    
090        /**
091         * Converts the supplied value to a string.
092         * <P>
093         * Subclasses may implement special formatting by overriding this method.
094         *
095         * @param value  the data value.
096         *
097         * @return Value as string.
098         */
099        public String valueToString(double value) {
100            return String.valueOf(value);
101        }
102    
103        /**
104         * Compares this tick unit to an arbitrary object.
105         *
106         * @param object  the object to compare against.
107         *
108         * @return <code>1</code> if the size of the other object is less than this,
109         *      <code>0</code> if both have the same size and <code>-1</code> this
110         *      size is less than the others.
111         */
112        public int compareTo(Object object) {
113    
114            if (object instanceof TickUnit) {
115                TickUnit other = (TickUnit) object;
116                if (this.size > other.getSize()) {
117                    return 1;
118                }
119                else if (this.size < other.getSize()) {
120                    return -1;
121                }
122                else {
123                    return 0;
124                }
125            }
126            else {
127                return -1;
128            }
129    
130        }
131    
132        /**
133         * Tests this unit for equality with another object.
134         *
135         * @param obj  the object.
136         *
137         * @return <code>true</code> or <code>false</code>.
138         */
139        public boolean equals(Object obj) {
140    
141            if (obj == null) {
142                return false;
143            }
144            if (obj == this) {
145                return true;
146            }
147            if (obj instanceof TickUnit) {
148                TickUnit tu = (TickUnit) obj;
149                return this.size == tu.size;
150            }
151            return false;
152    
153        }
154    
155        /**
156         * Returns a hash code for this instance.
157         * 
158         * @return A hash code.
159         */
160        public int hashCode() {
161            final long temp = size != +0.0d ? Double.doubleToLongBits(size) : 0L;
162            return (int) (temp ^ (temp >>> 32));
163        }
164    
165    }