001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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, 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
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 }