www.pudn.com > jfreechart-0.9.12.zip > TickUnit.java

/* ====================================== 
 * JFreeChart : a free Java chart library 
 * ====================================== 
 * 
 * Project Info:  http://www.jfree.org/jfreechart/index.html 
 * Project Lead:  David Gilbert (david.gilbert@object-refinery.com); 
 * 
 * (C) Copyright 2000-2003, by Object Refinery Limited and Contributors. 
 * 
 * This library is free software; you can redistribute it and/or modify it under the terms 
 * of the GNU Lesser General Public License as published by the Free Software Foundation; 
 * either version 2.1 of the License, or (at your option) any later version. 
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 * See the GNU Lesser General Public License for more details. 
 * 
 * You should have received a copy of the GNU Lesser General Public License along with this 
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
 * Boston, MA 02111-1307, USA. 
 * 
 * ------------- 
 * TickUnit.java 
 * ------------- 
 * (C) Copyright 2001-2003, by Object Refinery Limited. 
 * 
 * Original Author:  David Gilbert (for Object Refinery Limited); 
 * Contributor(s):   -; 
 * 
 * $Id: TickUnit.java,v 1.3 2003/06/13 15:45:57 mungady Exp $ 
 * 
 * Changes (from 19-Dec-2001) 
 * -------------------------- 
 * 19-Dec-2001 : Added standard header (DG); 
 * 01-May-2002 : Changed the unit size from Number to double (DG); 
 * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG); 
 * 08-Nov-2002 : Moved to new package com.jrefinery.chart.axis (DG); 
 * 26-Mar-2003 : Implemented Serializable (DG); 
 * 
 */ 
 
package org.jfree.chart.axis; 
 
import java.io.Serializable; 
 
/** 
 * Base class representing a tick unit.  This determines the spacing of the 
 * tick marks on an axis. 
 * 
 
 * This class (and any subclasses) should be immutable, the reason being that 
 * ORDERED collections of tick units are maintained and if one instance can be 
 * changed, it may destroy the order of the collection that it belongs to. 
 * In addition, if the implementations are immutable, they can belong to 
 * multiple collections. 
 * 
 * @see ValueAxis 
 * 
 * @author David Gilbert 
 */ 
public abstract class TickUnit implements Comparable, Serializable { 
 
    /** The size of the tick unit. */ 
    private double size; 
 
    /** 
     * Constructs a new tick unit. 
     * 
     * @param size  the tick unit size. 
     */ 
    public TickUnit(double size) { 
        this.size = size; 
    } 
 
    /** 
     * Returns the size of the tick unit. 
     * 
     * @return the size of the tick unit. 
     */ 
    public double getSize() { 
        return this.size; 
    } 
 
    /** 
     * Converts the supplied value to a string. 
     * 
 
     * Subclasses may implement special formatting by overriding this method. 
     * 
     * @param value  the data value. 
     * 
     * @return value as string. 
     */ 
    public String valueToString(double value) { 
        return String.valueOf(value); 
    } 
 
    /** 
     * Compares this tick unit to an arbitrary object. 
     * 
     * @param object  the object to compare against. 
     * 
     * @return 1 if the size of the other object is less than this, 
     *      0 if both have the same size and -1 this 
     *      size is less than the others. 
     */ 
    public int compareTo(Object object) { 
 
        if (object instanceof TickUnit) { 
            TickUnit other = (TickUnit) object; 
            if (this.size > other.getSize()) { 
                return 1; 
            } 
            else if (this.size < other.getSize()) { 
                return -1; 
            } 
            else { 
                return 0; 
            } 
        } 
        else { 
            return -1; 
        } 
 
    } 
 
    /** 
     * Tests this unit for equality with another object. 
     * 
     * @param obj  the object. 
     * 
     * @return true or false. 
     */ 
    public boolean equals(Object obj) { 
 
        if (obj == null) { 
            return false; 
        } 
 
        if (obj == this) { 
            return true; 
        } 
 
        if (obj instanceof TickUnit) { 
            TickUnit tu = (TickUnit) obj; 
            return this.size == tu.size; 
        } 
 
        return false; 
 
    } 
 
}