Pad string
/*
* Static String formatting and query routines.
* Copyright (C) 2001-2005 Stephen Ostermiller
* http://ostermiller.org/contact.pl?regarding=Java+Utilities
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
* See COPYING.TXT for details.
*/
import java.util.HashMap;
import java.util.regex.Pattern;
/**
* Utilities for String formatting, manipulation, and queries.
* More information about this class is available from <a target="_top" href=
* "http://ostermiller.org/utils/StringHelper.html">ostermiller.org</a>.
*
* @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
* @since ostermillerutils 1.00.00
*/
public class StringHelper {
/**
* Pad the beginning of the given String with spaces until
* the String is of the given length.
* <p>
* If a String is longer than the desired length,
* it will not be truncated, however no padding
* will be added.
*
* @param s String to be padded.
* @param length desired length of result.
* @return padded String.
* @throws NullPointerException if s is null.
*
* @since ostermillerutils 1.00.00
*/
public static String prepad(String s, int length){
return prepad(s, length, ' ');
}
/**
* Pre-pend the given character to the String until
* the result is the desired length.
* <p>
* If a String is longer than the desired length,
* it will not be truncated, however no padding
* will be added.
*
* @param s String to be padded.
* @param length desired length of result.
* @param c padding character.
* @return padded String.
* @throws NullPointerException if s is null.
*
* @since ostermillerutils 1.00.00
*/
public static String prepad(String s, int length, char c){
int needed = length - s.length();
if (needed <= 0){
return s;
}
char padding[] = new char[needed];
java.util.Arrays.fill(padding, c);
StringBuffer sb = new StringBuffer(length);
sb.append(padding);
sb.append(s);
return sb.toString();
}
/**
* Pad the end of the given String with spaces until
* the String is of the given length.
* <p>
* If a String is longer than the desired length,
* it will not be truncated, however no padding
* will be added.
*
* @param s String to be padded.
* @param length desired length of result.
* @return padded String.
* @throws NullPointerException if s is null.
*
* @since ostermillerutils 1.00.00
*/
public static String postpad(String s, int length){
return postpad(s, length, ' ');
}
/**
* Append the given character to the String until
* the result is the desired length.
* <p>
* If a String is longer than the desired length,
* it will not be truncated, however no padding
* will be added.
*
* @param s String to be padded.
* @param length desired length of result.
* @param c padding character.
* @return padded String.
* @throws NullPointerException if s is null.
*
* @since ostermillerutils 1.00.00
*/
public static String postpad(String s, int length, char c){
int needed = length - s.length();
if (needed <= 0){
return s;
}
char padding[] = new char[needed];
java.util.Arrays.fill(padding, c);
StringBuffer sb = new StringBuffer(length);
sb.append(s);
sb.append(padding);
return sb.toString();
}
/**
* Pad the beginning and end of the given String with spaces until
* the String is of the given length. The result is that the original
* String is centered in the middle of the new string.
* <p>
* If the number of characters to pad is even, then the padding
* will be split evenly between the beginning and end, otherwise,
* the extra character will be added to the end.
* <p>
* If a String is longer than the desired length,
* it will not be truncated, however no padding
* will be added.
*
* @param s String to be padded.
* @param length desired length of result.
* @return padded String.
* @throws NullPointerException if s is null.
*
* @since ostermillerutils 1.00.00
*/
public static String midpad(String s, int length){
return midpad(s, length, ' ');
}
/**
* Pad the beginning and end of the given String with the given character
* until the result is the desired length. The result is that the original
* String is centered in the middle of the new string.
* <p>
* If the number of characters to pad is even, then the padding
* will be split evenly between the beginning and end, otherwise,
* the extra character will be added to the end.
* <p>
* If a String is longer than the desired length,
* it will not be truncated, however no padding
* will be added.
*
* @param s String to be padded.
* @param length desired length of result.
* @param c padding character.
* @return padded String.
* @throws NullPointerException if s is null.
*
* @since ostermillerutils 1.00.00
*/
public static String midpad(String s, int length, char c){
int needed = length - s.length();
if (needed <= 0){
return s;
}
int beginning = needed / 2;
int end = beginning + needed % 2;
char prepadding[] = new char[beginning];
java.util.Arrays.fill(prepadding, c);
char postpadding[] = new char[end];
java.util.Arrays.fill(postpadding, c);
StringBuffer sb = new StringBuffer(length);
sb.append(prepadding);
sb.append(s);
sb.append(postpadding);
return sb.toString();
}
}