jfreechart example source code file (StandardTickUnitSource.java)

This example jfreechart source code file (StandardTickUnitSource.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

decimalformat, decimalformat, io, log_10_value, log_10_value, serializable, standardtickunitsource, standardtickunitsource, text, tickunit, tickunit, tickunitsource

The jfreechart StandardTickUnitSource.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ---------------------------
 * StandardTickUnitSource.java
 * ---------------------------
 * (C) Copyright 2003-2008, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 23-Sep-2003 : Version 1 (DG);
 * 25-Oct-2007 : Implemented Serializable and equals() method (DG);
 *
 */

package org.jfree.chart.axis;

import java.io.Serializable;
import java.text.DecimalFormat;

/**
 * A source that can used by the {@link NumberAxis} class to obtain a
 * suitable {@link TickUnit}.  Instances of this class are {@link Serializable}
 * from version 1.0.7 onwards.  Cloning is not supported, because instances
 * are immutable.
 */
public class StandardTickUnitSource implements TickUnitSource, Serializable {

    /** Constant for log(10.0). */
    private static final double LOG_10_VALUE = Math.log(10.0);

    /**
     * Default constructor.
     */
    public StandardTickUnitSource() {
        super();
    }

    /**
     * Returns a tick unit that is larger than the supplied unit.
     *
     * @param unit  the unit (<code>null not permitted).
     *
     * @return A tick unit that is larger than the supplied unit.
     */
    public TickUnit getLargerTickUnit(TickUnit unit) {
        double x = unit.getSize();
        double log = Math.log(x) / LOG_10_VALUE;
        double higher = Math.ceil(log);
        return new NumberTickUnit(Math.pow(10, higher),
                new DecimalFormat("0.0E0"));
    }

    /**
     * Returns the tick unit in the collection that is greater than or equal
     * to (in size) the specified unit.
     *
     * @param unit  the unit (<code>null not permitted).
     *
     * @return A unit from the collection.
     */
    public TickUnit getCeilingTickUnit(TickUnit unit) {
        return getLargerTickUnit(unit);
    }

    /**
     * Returns the tick unit in the collection that is greater than or equal
     * to the specified size.
     *
     * @param size  the size.
     *
     * @return A unit from the collection.
     */
    public TickUnit getCeilingTickUnit(double size) {
        double log = Math.log(size) / LOG_10_VALUE;
        double higher = Math.ceil(log);
        return new NumberTickUnit(Math.pow(10, higher),
                new DecimalFormat("0.0E0"));
    }

    /**
     * Tests this instance for equality with an arbitrary object.
     *
     * @param obj  the object (<code>null permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        return (obj instanceof StandardTickUnitSource);
    }

    /**
     * Returns a hash code for this instance.
     *
     * @return A hash code.
     */
    public int hashCode() {
        return 0;
    }

}