    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    025 * Other names may be trademarks of their respective owners.]
    026 *
    027 * --------------------
    028 * HexNumberFormat.java
    029 * --------------------
    030 * (C) Copyright 2007, 2008, by Richard West and Contributors.
    031 *
    032 * Original Author:  Richard West, Advanced Micro Devices, Inc.;
    033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
    034 *
    035 * Changes:
    036 * --------
    037 * 14-Jun-2007 : Version 1 (RW);
    038 *
    039 */
    040
    041package org.jfree.chart.util;
    042
    043import java.text.FieldPosition;
    044import java.text.NumberFormat;
    045import java.text.ParsePosition;
    046
    047/**
    048 * A custom number formatter that formats numbers as hexadecimal strings.
    049 * There are some limitations, so be careful using this class.
    050 *
    051 * @since 1.0.6
    052 */
    053public class HexNumberFormat extends NumberFormat {
    054
    055    /** Number of hexadecimal digits for a byte. */
    056    public static final int BYTE = 2;
    057
    058    /** Number of hexadecimal digits for a word. */
    059    public static final int WORD = 4;
    060
    061    /** Number of hexadecimal digits for a double word. */
    062    public static final int DWORD = 8;
    063
    064    /** Number of hexadecimal digits for a quad word. */
    065    public static final int QWORD = 16;
    066
    067    /** The number of digits (shorter strings will be left padded). */
    068    private int m_numDigits = DWORD;
    069
    070    /**
    071     * Creates a new instance with 8 digits.
    072     */
    073    public HexNumberFormat() {
    074        this(DWORD);
    075    }
    076
    077    /**
    078     * Creates a new instance with the specified number of digits.
    079
    080     * @param digits  the digits.
    081     */
    082    public HexNumberFormat(int digits) {
    083        super();
    084        this.m_numDigits = digits;
    085    }
    086
    087    /**
    088     * Returns the number of digits.
    089     *
    090     * @return The number of digits.
    091     */
    092    public final int getNumberOfDigits() {
    093        return this.m_numDigits;
    094    }
    095
    096    /**
    097     * Sets the number of digits.
    098     *
    099     * @param digits  the number of digits.
    100     */
    101    public void setNumberOfDigits(int digits) {
    102        this.m_numDigits = digits;
    103    }
    104
    105    /**
    106     * Formats the specified number as a hexadecimal string.  The decimal
    107     * fraction is ignored.
    108     *
    109     * @param number  the number to format.
    110     * @param toAppendTo  the buffer to append to (ignored here).
    111     * @param pos  the field position (ignored here).
    112     *
    113     * @return The string buffer.
    114     */
    115    public StringBuffer format(double number, StringBuffer toAppendTo,
    116            FieldPosition pos) {
    117        return format((long) number, toAppendTo, pos);
    118    }
    119
    120    /**
    121     * Formats the specified number as a hexadecimal string.  The decimal
    122     * fraction is ignored.
    123     *
    124     * @param number  the number to format.
    125     * @param toAppendTo  the buffer to append to (ignored here).
    126     * @param pos  the field position (ignored here).
    127     *
    128     * @return The string buffer.
    129     */
    130    public StringBuffer format(long number, StringBuffer toAppendTo,
    131            FieldPosition pos) {
    132        String l_hex = Long.toHexString(number).toUpperCase();
    133
    134        int l_pad = this.m_numDigits - l_hex.length();
    135        l_pad = (0 < l_pad) ? l_pad : 0;
    136
    137        StringBuffer l_extended = new StringBuffer("0x");
    138        for (int i = 0; i < l_pad; i++) {
    139            l_extended.append(0);
    140        }
    141        l_extended.append(l_hex);
    142
    143        return l_extended;
    144    }
    145
    146    /**
    147     * Parsing is not implemented, so this method always returns
    148     * <code>null</code>.
    149     *
    150     * @param source  ignored.
    151     * @param parsePosition  ignored.
    152     *
    153     * @return Always <code>null</code>.
    154     */
    155    public Number parse (String source, ParsePosition parsePosition) {
    156        return null; // don't bother with parsing
    157    }
    158
    159}