    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2007, 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     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
    025     * in the United States and other countries.]
    026     *
    027     * --------------------
    028     * HexNumberFormat.java
    029     * --------------------
    030     * (C) Copyright 2007, 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
    041    package org.jfree.chart.util;
    042
    043    import java.text.FieldPosition;
    044    import java.text.NumberFormat;
    045    import 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     */
    053    public 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    }