    001/* ===========================================================
    002 * Orson Charts : a 3D chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C)opyright 2013-2016, by Object Refinery Limited.  All rights reserved.
    006 *
    007 * http://www.object-refinery.com/orsoncharts/index.html
    008 *
    009 * This program is free software: you can redistribute it and/or modify
    010 * it under the terms of the GNU General Public License as published by
    011 * the Free Software Foundation, either version 3 of the License, or
    012 * (at your option) any later version.
    013 *
    014 * This program is distributed in the hope that it will be useful,
    015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
    016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    017 * GNU General Public License for more details.
    018 *
    019 * You should have received a copy of the GNU General Public License
    020 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    021 *
    022 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    023 * Other names may be trademarks of their respective owners.]
    024 *
    025 * If you do not wish to be bound by the terms of the GPL, an alternative
    026 * commercial license can be purchased.  For details, please see visit the
    027 * Orson Charts home page:
    028 *
    029 * http://www.object-refinery.com/orsoncharts/index.html
    030 *
    031 */
    032
    033package com.orsoncharts.axis;
    034
    035import java.io.Serializable;
    036import java.text.DecimalFormat;
    037import java.text.Format;
    038import com.orsoncharts.util.ArgChecks;
    039
    040/**
    041 * A {@link TickSelector} implementation that selects tick units in multiples
    042 * of 1, 2 and 5 and only displays integer values.
    043 * <br><br>
    044 * NOTE: This class is serializable, but the serialization format is subject
    045 * to change in future releases and should not be relied upon for persisting
    046 * instances of this class.
    047 *
    048 * @since 1.5
    049 */
    050@SuppressWarnings("serial")
    051public class IntegerTickSelector implements TickSelector, Serializable {
    052
    053    private int power = 0;
    054
    055    private int factor = 1;
    056
    057    /**
    058     * Creates a new instance.
    059     */
    060    public IntegerTickSelector() {
    061        this.power = 0;
    062        this.factor = 1;
    063    }
    064
    065    /**
    066     * Selects and returns a standard tick size that is greater than or equal to
    067     * the specified reference value and, ideally, as close to it as possible
    068     * (to minimise the number of iterations used by axes to determine the tick
    069     * size to use).  After a call to this method, the
    070     * {@link #getCurrentTickSize()} method should return the selected tick
    071     * size (there is a "pointer" to this tick size), the {@link #next()}
    072     * method should move the pointer to the next (larger) standard tick size,
    073     * and the {@link #previous()} method should move the pointer to the
    074     * previous (smaller) standard tick size.
    075     *
    076     * @param reference  the reference value (must be positive and finite).
    077     *
    078     * @return The selected tick size.
    079     */
    080    @Override
    081    public double select(double reference) {
    082        ArgChecks.finitePositiveRequired(reference, "reference");
    083        this.power = (int) Math.ceil(Math.log10(reference));
    084        this.factor = 1;
    085        return getCurrentTickSize();
    086    }
    087
    088    /**
    089     * Move the cursor to the next (larger) tick size, if there is one.
    090     * Returns {@code true} in the case that the cursor is moved, and
    091     * {@code false} where there are a finite number of tick sizes and the
    092     * current tick size is the largest available.
    093     */
    094    @Override
    095    public boolean next() {
    096        if (factor == 1) {
    097            factor = 2;
    098            return true;
    099        }
    100        if (factor == 2) {
    101            factor = 5;
    102            return true;
    103        }
    104        if (factor == 5) {
    105            power++;
    106            factor = 1;
    107            return true;
    108        }
    109        throw new IllegalStateException("We should never get here.");
    110    }
    111
    112    /**
    113     * Move the cursor to the previous (smaller) tick size, if there is one.
    114     * Returns {@code true} in the case that the cursor is moved, and
    115     * {@code false} where there are a finite number of tick sizes and the
    116     * current tick size is the smallest available.
    117     */
    118    @Override
    119    public boolean previous() {
    120        if (factor == 1) {
    121            if (power == 0) {
    122                return false;
    123            }
    124            factor = 5;
    125            power--;
    126            return true;
    127        }
    128        if (factor == 2) {
    129            factor = 1;
    130            return true;
    131        }
    132        if (factor == 5) {
    133            factor = 2;
    134            return true;
    135        }
    136        throw new IllegalStateException("We should never get here.");
    137    }
    138
    139    @Override
    140    public double getCurrentTickSize() {
    141        return this.factor * Math.pow(10.0, this.power);
    142    }
    143
    144    private DecimalFormat df0 = new DecimalFormat("#,##0");
    145
    146    @Override
    147    public Format getCurrentTickLabelFormat() {
    148        if (power >= 0 && power <= 6) {
    149            return df0;
    150        }
    151        return new DecimalFormat("0.0000E0");
    152    }
    153
    154    /**
    155     * Tests this instance for equality with an arbitrary object.
    156     *
    157     * @param obj  the object ({@code null} permitted).
    158     *
    159     * @return A boolean.
    160     */
    161    @Override
    162    public boolean equals(Object obj) {
    163        if (obj ==  this) {
    164            return true;
    165        }
    166        if (!(obj instanceof IntegerTickSelector)) {
    167            return false;
    168        }
    169        return true;
    170    }
    171
    172}