jfreechart example source code file (HexNumberFormat.java)

This example jfreechart source code file (HexNumberFormat.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

byte, dword, dword, fieldposition, hexnumberformat, hexnumberformat, number, parseposition, qword, string, string, stringbuffer, stringbuffer, text, word

The jfreechart HexNumberFormat.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, 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.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * --------------------
 * HexNumberFormat.java
 * --------------------
 * (C) Copyright 2007, 2008, by Richard West and Contributors.
 *
 * Original Author:  Richard West, Advanced Micro Devices, Inc.;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * Changes:
 * --------
 * 14-Jun-2007 : Version 1 (RW);
 *
 */

package org.jfree.chart.util;

import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParsePosition;

/**
 * A custom number formatter that formats numbers as hexadecimal strings.
 * There are some limitations, so be careful using this class.
 *
 * @since 1.0.6
 */
public class HexNumberFormat extends NumberFormat {

    /** Number of hexadecimal digits for a byte. */
    public static final int BYTE = 2;

    /** Number of hexadecimal digits for a word. */
    public static final int WORD = 4;

    /** Number of hexadecimal digits for a double word. */
    public static final int DWORD = 8;

    /** Number of hexadecimal digits for a quad word. */
    public static final int QWORD = 16;

    /** The number of digits (shorter strings will be left padded). */
    private int m_numDigits = DWORD;

    /**
     * Creates a new instance with 8 digits.
     */
    public HexNumberFormat() {
        this(DWORD);
    }

    /**
     * Creates a new instance with the specified number of digits.

     * @param digits  the digits.
     */
    public HexNumberFormat(int digits) {
        super();
        this.m_numDigits = digits;
    }

    /**
     * Returns the number of digits.
     *
     * @return The number of digits.
     */
    public final int getNumberOfDigits() {
        return this.m_numDigits;
    }

    /**
     * Sets the number of digits.
     *
     * @param digits  the number of digits.
     */
    public void setNumberOfDigits(int digits) {
        this.m_numDigits = digits;
    }

    /**
     * Formats the specified number as a hexadecimal string.  The decimal
     * fraction is ignored.
     *
     * @param number  the number to format.
     * @param toAppendTo  the buffer to append to (ignored here).
     * @param pos  the field position (ignored here).
     *
     * @return The string buffer.
     */
    public StringBuffer format(double number, StringBuffer toAppendTo,
            FieldPosition pos) {
        return format((long) number, toAppendTo, pos);
    }

    /**
     * Formats the specified number as a hexadecimal string.  The decimal
     * fraction is ignored.
     *
     * @param number  the number to format.
     * @param toAppendTo  the buffer to append to (ignored here).
     * @param pos  the field position (ignored here).
     *
     * @return The string buffer.
     */
    public StringBuffer format(long number, StringBuffer toAppendTo,
            FieldPosition pos) {
        String l_hex = Long.toHexString(number).toUpperCase();

        int l_pad = this.m_numDigits - l_hex.length();
        l_pad = (0 < l_pad) ? l_pad : 0;

        StringBuffer l_extended = new StringBuffer("0x");
        for (int i = 0; i < l_pad; i++) {
            l_extended.append(0);
        }
        l_extended.append(l_hex);

        return l_extended;
    }

    /**
     * Parsing is not implemented, so this method always returns
     * <code>null.
     *
     * @param source  ignored.
     * @param parsePosition  ignored.
     *
     * @return Always <code>null.
     */
    public Number parse (String source, ParsePosition parsePosition) {
        return null; // don't bother with parsing
    }

}