NumberTickUnitSource.java

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2014, 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.
 *
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 *
 * -------------------------
 * NumberTickUnitSource.java
 * -------------------------
 * (C) Copyright 2014, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 18-Mar-2014 : Version 1 (DG);
 *
 */

package org.jfree.chart.axis;

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

/**
 * A tick unit source implementation that returns NumberTickUnit instances 
 * that are multiples of 1 or 5 times some power of 10.
 * 
 * @since 1.0.18
 */
public class NumberTickUnitSource implements TickUnitSource, Serializable {

    private int power = 0;
    
    private int factor = 1;

    /**
     * Creates a new instance.
     */
    public NumberTickUnitSource() {
        this.power = 0;
        this.factor = 1;
    }
    
    @Override
    public TickUnit getLargerTickUnit(TickUnit unit) {
        TickUnit t = getCeilingTickUnit(unit);
        if (t.equals(unit)) {
            next();
            t = new NumberTickUnit(getTickSize(), getTickLabelFormat(), 
                    getMinorTickCount());
        }
        return t; 
    }

    @Override
    public TickUnit getCeilingTickUnit(TickUnit unit) {
        return getCeilingTickUnit(unit.getSize());
    }

    @Override
    public TickUnit getCeilingTickUnit(double size) {
        this.power = (int) Math.ceil(Math.log10(size));
        this.factor = 1;
        return new NumberTickUnit(getTickSize(), getTickLabelFormat(), 
                getMinorTickCount());
    }
    
    private boolean next() {
        if (factor == 1) {
            factor = 5;
            return true;
        } 
        if (factor == 5) {
            power++;
            factor = 1;
            return true;
        } 
        throw new IllegalStateException("We should never get here.");
    }

    private boolean previous() {
        if (factor == 1) {
            factor = 5;
            power--;
            return true;
        } 
        if (factor == 5) {
            factor = 1;
            return true;
        } 
        throw new IllegalStateException("We should never get here.");
    }

    private double getTickSize() {
        return this.factor * Math.pow(10.0, this.power);
    }
    
    private DecimalFormat dfNeg4 = new DecimalFormat("0.0000");
    private DecimalFormat dfNeg3 = new DecimalFormat("0.000");
    private DecimalFormat dfNeg2 = new DecimalFormat("0.00");
    private DecimalFormat dfNeg1 = new DecimalFormat("0.0");
    private DecimalFormat df0 = new DecimalFormat("#,##0");

    private NumberFormat getTickLabelFormat() {
        if (power == -4) {
            return dfNeg4;
        }
        if (power == -3) {
            return dfNeg3;
        }
        if (power == -2) {
            return dfNeg2;
        }
        if (power == -1) {
            return dfNeg1;
        }
        if (power >= 0 && power <= 6) {
            return df0;
        }
        return new DecimalFormat("#.##########");
    }
    
    private int getMinorTickCount() {
        if (factor == 1) {
            return 10;
        } else if (factor == 5) {
            return 5;
        }
        return 0;
    }
    
    @Override
    public boolean equals(Object obj) {
        return (obj instanceof NumberTickUnitSource);
    }
}