Format.java
/*
* Copyright 2003-2004, Franz-Josef Elmer, All rights reserved
*
* 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 program 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
* (http://www.gnu.org/copyleft/lesser.html).
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package jcckit.util;
import java.util.Vector;
/**
* A helper class for formatting numbers according to
* a <tt>printf</tt>-like format string. Each instance of
* this class is initialized by a format string for a
* single number.
*
* @author Franz-Josef Elmer
*/
public class Format implements TicLabelFormat {
/**
* Creates a new instance based of specified key-value pair of the
* specified configuration parameters.
* @param config Config parameters.
* @param key The key of the key-value pair in <tt>config</tt> containing
* the format string.
* @return <tt>null</tt> if undefined key-value pair or format string
* is an empty string.
* @throws FactoryException if the format string is invalid.
*/
public static Format create(ConfigParameters config, String key) {
Format result = null;
String format = config.get(key, null);
if (format != null && format.length() > 0) {
try {
result = new Format(format);
} catch (Exception e) {
throw new FactoryException(config, key, e);
}
}
return result;
}
private final FormatElement[] _formatElements;
private final Vector _staticParts;
/**
* Creates an instance for the specified format string.
* The format string is an alternation of some static texts and
* format elements.
* A format element has to start with `%` and it must end with
* one of the following format descriptors:
* <table border=0 cellpadding=5>
* <tr><td><tt>d</tt></td>
* <td>decimal integer</td></tr>
* <tr><td><tt>o</tt></td>
* <td>octal integer</td></tr>
* <tr><td><tt>x</tt></td>
* <td>hex integer</td></tr>
* <tr><td><tt>f</tt></td>
* <td>floating point number with a fixed decimal point</td></tr>
* <tr><td><tt>e, E</tt></td>
* <td>floating point number in logarithmic format</td></tr>
* <tr><td><tt>g, G</tt></td>
* <td>floating point number rendered either in fixed-decimal
* format of logarithmic format depending on the size of
* the mantissa.</td></tr>
* </table>
* The characters between `%` and the decriptor are optional.
* They can be grouped into
* <ul><li>modifier<br>
* it is
* <ul><li>'-' if the formated result should be flushed left
* <li>'+' if the sign should be always appear
* <li>'0' if the leading space should be filled with zeros
* </ul>
* <li>width<br>
* a decimal number given the minimum number of characters
* of the result
* <li>precision
* </ul>
* A plain `%` is coded as `%%`.
* @param formatString The format string.
* @exception IllegalArgumentException if invalid format string.
*/
public Format(String formatString) {
_staticParts = new Vector();
Vector formatElements = new Vector();
StringBuffer part = new StringBuffer();
boolean insideFormatElement = false;
boolean atPercentSymbol = false;
for (int i = 0, n = formatString.length(); i < n; i++) {
char c = formatString.charAt(i);
if (insideFormatElement) {
part.append(c);
if (FormatElement.DESCRIPTORS.indexOf(c) >= 0) {
formatElements.addElement(new String(part));
part.setLength(0);
insideFormatElement = false;
}
} else if (atPercentSymbol) {
atPercentSymbol = false;
if (c != '%') {
_staticParts.addElement(new String(part));
part.setLength(0);
insideFormatElement = true;
}
part.append(c);
if (FormatElement.DESCRIPTORS.indexOf(c) >= 0) {
formatElements.addElement(new String(part));
part.setLength(0);
insideFormatElement = false;
}
} else {
if (c == '%') {
atPercentSymbol = true;
} else {
part.append(c);
}
}
}
if (insideFormatElement) {
formatElements.addElement(new String(part));
} else {
_staticParts.addElement(new String(part));
}
_formatElements = new FormatElement[formatElements.size()];
for (int i = 0; i < _formatElements.length; i++) {
_formatElements[i]
= new FormatElement((String) formatElements.elementAt(i));
}
}
/**
* Format a number.
* If there are no format elements the numbers will be ignored.
* If there are more than one format elements the
* additional format elements will be ignored and only the static parts
* are taken.
* @param number Number to be formated.
* @return Formated number.
*/
public String form(long number) {
StringBuffer result = new StringBuffer();
result.append(_staticParts.elementAt(0));
if (_formatElements.length > 0) {
_formatElements[0].form(result, number);
}
return appendRest(result);
}
/**
* Format a number.
* If there are no format elements the numbers will be ignored.
* If there are more than one format elements the
* additional format elements will be ignored and only the static parts
* are taken.
* @param number Number to be formated.
* @return Formated number.
*/
public String form(double number) {
StringBuffer result = new StringBuffer();
result.append(_staticParts.elementAt(0));
if (_formatElements.length > 0) {
_formatElements[0].form(result, number);
}
return appendRest(result);
}
private String appendRest(StringBuffer buffer) {
for (int i = 1, n = _staticParts.size(); i < n; i++) {
buffer.append(_staticParts.elementAt(i));
}
return new String(buffer);
}
/**
* Format an array of double numbers.
* If there are less format elements than numbers the additional numbers
* will be ignored. If there are less numbers than format elements the
* additional format elements will be ignored and only the static parts
* are taken.
* @param numbers Numbers to be formated.
* @return Formated numbers.
*/
public String form(double[] numbers) {
StringBuffer result = new StringBuffer();
for (int i = 0, n = _staticParts.size(); i < n; i++) {
result.append(_staticParts.elementAt(i));
if (i < _formatElements.length && i < numbers.length) {
_formatElements[i].form(result, numbers[i]);
}
}
return new String(result);
}
}