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POJava is a simple, light-weight Java-based library providing a variety of
utilities for data transformation.
package org.pojava.util;
/*
Copyright 2008-09 John Pile
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* A set of methods for performing string manipulation, mostly to support internal needs without
* requiring external libraries.
*/
public class StringTool {
/**
* Returns a zero-based offset if the left-most characters of str match all of the
* characters of any member of list.
*
* @param list
* @param str
* @return -1 if no match, else indexed offset
*/
public static int indexedStartMatch(String[] list, String str) {
for (int i = 0; i < list.length; i++) {
int len = list[i].length();
if (str.length() >= len && list[i].equals(str.substring(0, len))) {
return i;
}
}
return -1;
}
/**
* True if a string matches /^[-]?[0-9]+$/
*
* @param s
* @return true if string is numeric
*/
public static boolean isInteger(String s) {
if (s == null || s.length() == 0)
return false;
char c = s.charAt(0);
if (s.length() == 1)
return c >= '0' && c <= '9';
return (c == '-' || c >= '0' && c <= '9') && onlyDigits(s.substring(1));
}
/**
* True if a string matches /^[tTyY1].*$/
* @param s
* @return true if string represents true
*/
public static boolean isTrue(String s) {
if (s == null || s.length() == 0)
return false;
char c = s.charAt(0);
return c=='t' || c=='T' || c=='y' || c=='Y' || c=='1';
}
/**
* True if a string has only digits in it.
*
* @param s
* @return true if string is composed of only digits.
*/
public static boolean onlyDigits(String s) {
if (s == null || s.length() == 0)
return false;
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (c < '0' || c > '9')
return false;
}
return true;
}
/**
* True if a string starts with a digit.
*
* @param s
* @return true if string starts with a digit.
*/
public static boolean startsWithDigit(String s) {
if (s == null || s.length() == 0)
return false;
char c = s.charAt(0);
return (c >= '0' && c <= '9');
}
/**
* Parse an integer from left-to-right until non-digit reached
*
* @param str
* @return first integer greedily matched from a string
*/
public static int parseIntFragment(String str) {
if (str == null) {
return 0;
}
int parsed = 0;
boolean isNeg = false;
char[] strip = str.toCharArray();
char c = strip[0];
if (c == '-') {
isNeg = true;
} else if (c >= '0' && c <= '9') {
parsed = c - '0';
} else {
return 0;
}
for (int i = 1; i < strip.length; i++) {
c = strip[i];
if (c >= '0' && c <= '9') {
parsed = 10 * parsed + c - '0';
} else {
break;
}
}
return isNeg ? -parsed : parsed;
}
/**
* Capitalize the first character of a String.
*
* @param str
* @return Capitalize the first character.
*/
public static String capitalize(String str) {
char[] chars = str.toCharArray();
chars[0] = Character.toUpperCase(chars[0]);
return new String(chars);
}
/**
* Convert strings of this_style to thisStyle.
*
* @param str
* @return camelCase from underscored_words
*/
public static String camelFromUnderscore(String str) {
if (str == null)
return null;
StringBuffer sb = new StringBuffer();
char[] a = str.toCharArray();
boolean up = false;
for (int i = 0; i < a.length; i++) {
char c = a[i];
if (c == '_') {
up = true;
} else {
if (up) {
up = false;
if (c >= '0' && c <= '9') {
sb.append('_');
sb.append(c);
} else {
sb.append(Character.toUpperCase(c));
}
} else {
if (c >= 'A' && c <= 'Z') {
c += 'a' - 'A';
}
sb.append(c);
}
}
}
return sb.toString();
}
/**
* Convert strings of thisStyle to this_style.
*
* @param str
* @return underscored_words from camelCase
*/
public static String underscoreFromCamel(String str) {
if (str == null)
return null;
StringBuffer sb = new StringBuffer();
char[] a = str.toCharArray();
for (int i = 0; i < a.length; i++) {
char c = a[i];
if (c >= 'A' && c <= 'Z') {
sb.append('_');
c += ('a' - 'A');
}
sb.append(c);
}
return sb.toString();
}
/**
* Collapses a string with whitespace characters, including carriage returns, into a
* one-line string with no spaces or tabs.
*
* @param str
* @return A string with all whitespace removed.
*/
public static String stripWhitespace(String str) {
char[] from = str.toCharArray();
char[] to = new char[from.length];
int f = 0;
int t = 0;
int last = from.length;
for (f = 0; f < last; f++) {
char c = from[f];
if (!(c == ' ' || c == '\t' || c == '\n' || c == '\r')) {
to[t++] = c;
}
}
return new String(to, 0, t);
}
/**
* Right-pad a string to a fixed width with spaces.
*
* @param str
* @param width
* @return Padded string of minimal width.
*/
public static String pad(String str, int width) {
if (width < str.length()) {
return str;
}
StringBuffer sb = new StringBuffer(width);
sb.append(str);
for (int i = 0; i < width - str.length(); i++) {
sb.append(' ');
}
return sb.toString();
}
}