Trim string from left or right : String format « Data Type « Java
Trim string from left or right
//package com.studiofortress.sf.util;
/**
* A fully static class, this contains helper methods for working with strings.
*
* @author Joseph Lenton
*/
public final class StringUtil
{
private static final char DEFAULT_TRIM_WHITESPACE = ' ';
/**
* No Constructor.
*/
private StringUtil() { }
/**
* Concatonates all the strings given together into one long string.
* @param strings An array of strings, cannot be null and cannot contain null.
* @return A string made by concatonating all the elements of strings together.
*/
public static String stringConcat(String ... strings)
{
/* Add up the total length of the strings, this is a small optimization
* for when were working with lots of long strings. */
int length = 0;
for (int i = 0; i < strings.length; i++) {
length += strings[i].length();
}
// append all strings together
final StringBuilder concatString = new StringBuilder(length);
for (int i = 0; i < strings.length; i++) {
concatString.append(strings[i]);
}
return concatString.toString();
}
/**
* Trims spaces from the left side of the string and returns the result.
* @param string The string to trim.
* @return A string with all spaces removed from the left side.
*/
public static String trimLeft(String string)
{
return trimLeft( string, DEFAULT_TRIM_WHITESPACE );
}
/**
* Trims the character given from the given string and returns the result.
* @param string The string to trim, cannot be null.
* @param trimChar The character to trim from the left of the given string.
* @return A string with the given character trimmed from the string given.
*/
public static String trimLeft(final String string, final char trimChar)
{
final int stringLength = string.length();
int i;
for (i = 0; i < stringLength && string.charAt(i) == trimChar; i++) {
/* increment i until it is at the location of the first char that
* does not match the trimChar given. */
}
if (i == 0) {
return string;
} else {
return string.substring(i);
}
}
/**
* Trims spaces from the right side of the string given and returns the
* result.
* @param string The string to trim, cannot be null.
* @return A string with all whitespace trimmed from the right side of it.
*/
public static String trimRight(final String string)
{
return trimRight(string, DEFAULT_TRIM_WHITESPACE);
}
/**
* Trims the character given from the right side of the string given. The
* result of this trimming is then returned.
* @param string The string to trim, cannot be null.
* @param trimChar The character to trim from the right side of the given string.
* @return The result of trimming the character given from the right side of the given string.
*/
public static String trimRight(final String string, final char trimChar)
{
final int lastChar = string.length() - 1;
int i;
for (i = lastChar; i >= 0 && string.charAt(i) == trimChar; i--) {
/* Decrement i until it is equal to the first char that does not
* match the trimChar given. */
}
if (i < lastChar) {
// the +1 is so we include the char at i
return string.substring(0, i+1);
} else {
return string;
}
}
/**
* Trims the character given from both left and right of the string given.
* For trimming whitespace you can simply use the String classes trim method.
* @param string The string to trim characters from, cannot be null.
* @param trimChar The character to trim from either side of the given string.
* @return A string with the given characters trimmed from either side.
*/
public static String trim(final String string, final char trimChar)
{
return trimLeft(trimRight(string, trimChar), trimChar);
}
}
