commons-lang-1.0.1.jar - Apache Commons Lang
commons-lang-1.0.1.jar is the JAR file for Apache Commons Lang 1.0.1, which
provides a host of helper utilities for the java.lang API.
JAR File Size and Download Location:
File name: commons-lang-1.0.1.jar File size: 63980 bytes Date modified: 11/22/2002 Download: Apache Commons Lang Website
✍: FYIcenter.com
⏎ org/apache/commons/lang/StringUtils.java
package org.apache.commons.lang;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.util.StringTokenizer;
import java.util.Iterator;
/**
* <p>Common <code>String</code> manipulation routines.</p>
*
* <p>Originally from
* <a href="http://jakarta.apache.org/turbine/">Turbine</a> and the
* GenerationJavaCore library.</p>
*
* @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
* @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
* @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
* @author <a href="mailto:bayard@generationjava.com">Henri Yandell</a>
* @author <a href="mailto:ed@apache.org">Ed Korthof</a>
* @author <a href="mailto:rand_mcneely@yahoo.com>Rand McNeely</a>
* @author <a href="mailto:scolebourne@joda.org>Stephen Colebourne</a>
* @author <a href="mailto:fredrik@westermarck.com>Fredrik Westermarck</a>
* @version $Id: StringUtils.java,v 1.18.2.1 2002/11/23 01:06:56 bayard Exp $
*/
public class StringUtils {
/**
* StringUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as <code>StringUtils.trim(" foo ");</code>.
* This constructor is public to permit tools that require a JavaBean instance
* to operate.
*/
public StringUtils() {
}
// Empty
//--------------------------------------------------------------------------
/**
* Removes control characters, including whitespace, from both ends of this
* string, handling null by returning an empty string.
*
* @see java.lang.String#trim()
* @param str the string to check
* @return the trimmed text (never <code>null</code>)
*/
public static String clean(String str) {
return (str == null ? "" : str.trim());
}
/**
* Removes control characters, including whitespace, from both ends of this
* string, handling null by returning null.
*
* @see java.lang.String#trim()
* @param str the string to check
* @return the trimmed text (or <code>null</code>)
*/
public static String trim(String str) {
return (str == null ? null : str.trim());
}
/**
* Deletes all 'space' characters from a String.
* Spaces are defined as {' ', '\t', '\r', '\n', '\b'}
* in line with the deprecated Character.isSpace
*
* @param str String target to delete spaces from
* @return the text without spaces
* @throws NullPointerException
*/
public static String deleteSpaces(String str) {
return CharSetUtils.delete(str, " \t\r\n\b");
}
/**
* Deletes all whitespace from a String.
* Whitespace is defined by Character.isWhitespace
*
* @param str String target to delete whitespace from
* @return the text without whitespace
* @throws NullPointerException
*/
public static String deleteWhitespace(String str) {
StringBuffer buffer = new StringBuffer();
int sz = str.length();
for (int i=0; i<sz; i++) {
if(!Character.isWhitespace(str.charAt(i))) {
buffer.append(str.charAt(i));
}
}
return buffer.toString();
}
/**
* Checks if a String is non null and is not empty (length > 0).
*
* @param str the string to check
* @return true if the String is non-null, and not length zero
*/
public static boolean isNotEmpty(String str) {
return (str != null && str.length() > 0);
}
/**
* Checks if a (trimmed) String is null or empty.
*
* @param str the string to check
* @return true if the String is null, or length zero once trimmed
*/
public static boolean isEmpty(String str) {
return (str == null || str.trim().length() == 0);
}
// Equals and IndexOf
//--------------------------------------------------------------------------
/**
* Compares two Strings, returning true if they are equal.
* Nulls are handled without exceptions. Two <code>null</code>
* references are considered equal. Comparison is case sensitive.
*
* @see java.lang.String#equals(Object)
* @param str1 the first string
* @param str2 the second string
* @return true if the Strings are equal, case sensitive, or both null
*/
public static boolean equals(String str1, String str2) {
return (str1 == null ? str2 == null : str1.equals(str2));
}
/**
* Compares two Strings, returning true if they are equal ignoring case.
* Nulls are handled without exceptions. Two <code>null</code>
* references are considered equal. Comparison is case insensitive.
* @see java.lang.String#equalsIgnoreCase(String)
* @param str1 the first string
* @param str2 the second string
* @return true if the Strings are equal, case insensitive, or both null
*/
public static boolean equalsIgnoreCase(String str1, String str2) {
return (str1 == null ? str2 == null : str1.equalsIgnoreCase(str2));
}
/**
* Find the earliest index of any of a set of potential substrings.
* Null string will return -1.
*
* @param str the string to check
* @param searchStrs the strings to search for
* @return the earliest index of any of the strings
* @throws NullPointerException if any of searchStrs[i] is null
*/
public static int indexOfAny(String str, String[] searchStrs) {
if ((str == null) || (searchStrs == null)) {
return -1;
}
int sz = searchStrs.length;
// String's can't have a MAX_VALUEth index.
int ret = Integer.MAX_VALUE;
int tmp = 0;
for (int i = 0; i < sz; i++) {
tmp = str.indexOf(searchStrs[i]);
if (tmp == -1) {
continue;
}
if (tmp < ret) {
ret = tmp;
}
}
return (ret == Integer.MAX_VALUE) ? -1 : ret;
}
/**
* Find the latest index of any of a set of potential substrings.
* Null string will return -1.
*
* @param str the string to check
* @param searchStrs the strings to search for
* @return the last index of any of the strings
* @throws NullPointerException if any of searchStrs[i] is null
*/
public static int lastIndexOfAny(String str, String[] searchStrs) {
if ((str == null) || (searchStrs == null)) {
return -1;
}
int sz = searchStrs.length;
int ret = -1;
int tmp = 0;
for (int i = 0; i < sz; i++) {
tmp = str.lastIndexOf(searchStrs[i]);
if (tmp > ret) {
ret = tmp;
}
}
return ret;
}
// Substring
//--------------------------------------------------------------------------
/**
* Gets a substring of the specified string avoiding exceptions.
* A negative start position can be used to start n characters from
* the end of the string.
*
* @param str the string to get the substring from
* @param start the position to start from, negative means
* count back from the end of the string by this many characters
* @return substring from start position
*/
public static String substring(String str, int start) {
if (str == null) {
return null;
}
// handle negatives, which means last n characters
if (start < 0) {
start = str.length() + start; // remember start is negative
}
if (start < 0) {
start = 0;
}
if (start > str.length()) {
return "";
}
return str.substring(start);
}
/**
* Gets a substring of the specified string avoiding exceptions.
* A negative start position can be used to start/end n characters
* from the end of the string.
*
* @param str the string to get the substring from
* @param start the position to start from, negative means
* count back from the end of the string by this many characters
* @param end the position to end at (exclusive), negative means
* count back from the end of the string by this many characters
* @return substring from start position to end positon
*/
public static String substring(String str, int start, int end) {
if (str == null) {
return null;
}
// handle negatives
if (end < 0) {
end = str.length() + end; // remember end is negative
}
if (start < 0) {
start = str.length() + start; // remember start is negative
}
// check length next
if (end > str.length()) {
// check this works.
end = str.length();
}
// if start is greater than end, return ""
if (start > end) {
return "";
}
if (start < 0) {
start = 0;
}
if (end < 0) {
end = 0;
}
return str.substring(start, end);
}
/**
* Gets the leftmost n characters of a string. If n characters are not
* available, or the string is null, the string will be returned
* without an exception.
*
* @param str the string to get the leftmost characters from
* @param len the length of the required string
* @return the leftmost characters
* @throws IllegalArgumentException if len is less than zero
*/
public static String left(String str, int len) {
if (len < 0) {
throw new IllegalArgumentException("Requested String length " + len + " is less than zero");
}
if ((str == null) || (str.length() <= len)) {
return str;
} else {
return str.substring(0, len);
}
}
/**
* Gets the rightmost n characters of a string. If n characters are not
* available, or the string is null, the string will be returned
* without an exception.
*
* @param str the string to get the rightmost characters from
* @param len the length of the required string
* @return the leftmost characters
* @throws IllegalArgumentException if len is less than zero
*/
public static String right(String str, int len) {
if (len < 0) {
throw new IllegalArgumentException("Requested String length " + len + " is less than zero");
}
if ((str == null) || (str.length() <= len)) {
return str;
} else {
return str.substring(str.length() - len);
}
}
/**
* Gets n characters from the middle of a string. If n characters are
* not available, the remainder of the string will be returned
* without an exception. If the string is null, null will be returned.
*
* @param str the string to get the characters from
* @param pos the position to start from
* @param len the length of the required string
* @return the leftmost characters
* @throws IndexOutOfBoundsException if pos is out of bounds
* @throws IllegalArgumentException if len is less than zero
*/
public static String mid(String str, int pos, int len) {
if ((pos < 0) ||
(str != null && pos > str.length())) {
throw new StringIndexOutOfBoundsException("String index " + pos + " is out of bounds");
}
if (len < 0) {
throw new IllegalArgumentException("Requested String length " + len + " is less than zero");
}
if (str == null) {
return null;
}
if (str.length() <= (pos + len)) {
return str.substring(pos);
} else {
return str.substring(pos, pos + len);
}
}
// Splitting
//--------------------------------------------------------------------------
/**
* Splits the provided text into a list, using whitespace as the separator.
* The separator is not included in the returned String array.
*
* @param str the string to parse
* @return an array of parsed Strings
*/
public static String[] split(String str) {
return split(str, null, -1);
}
/**
* @see #split(String, String, int)
*/
public static String[] split(String text, String separator) {
return split(text, separator, -1);
}
/**
* Splits the provided text into a list, based on a given separator.
* The separator is not included in the returned String array.
* The maximum number of splits to perfom can be controlled.
* A null separator will cause parsing to be on whitespace.
*
* <p>This is useful for quickly splitting a string directly into
* an array of tokens, instead of an enumeration of tokens (as
* <code>StringTokenizer</code> does).
*
* @param str The string to parse.
* @param separator Characters used as the delimiters. If
* <code>null</code>, splits on whitespace.
* @param max The maximum number of elements to include in the
* list. A zero or negative value implies no limit.
* @return an array of parsed Strings
*/
public static String[] split(String str, String separator, int max) {
StringTokenizer tok = null;
if (separator == null) {
// Null separator means we're using StringTokenizer's default
// delimiter, which comprises all whitespace characters.
tok = new StringTokenizer(str);
} else {
tok = new StringTokenizer(str, separator);
}
int listSize = tok.countTokens();
if (max > 0 && listSize > max) {
listSize = max;
}
String[] list = new String[listSize];
int i = 0;
int lastTokenBegin = 0;
int lastTokenEnd = 0;
while (tok.hasMoreTokens()) {
if (max > 0 && i == listSize - 1) {
// In the situation where we hit the max yet have
// tokens left over in our input, the last list
// element gets all remaining text.
String endToken = tok.nextToken();
lastTokenBegin = str.indexOf(endToken, lastTokenEnd);
list[i] = str.substring(lastTokenBegin);
break;
} else {
list[i] = tok.nextToken();
lastTokenBegin = str.indexOf(list[i], lastTokenEnd);
lastTokenEnd = lastTokenBegin + list[i].length();
}
i++;
}
return list;
}
// Joining
//--------------------------------------------------------------------------
/**
* Concatenates elements of an array into a single string.
* The difference from join is that concatenate has no delimiter.
*
* @param array the array of values to concatenate.
* @return the concatenated string.
*/
public static String concatenate(Object[] array) {
return join(array, "");
}
/**
* Joins the elements of the provided array into a single string
* containing the provided list of elements.
* No delimiter is added before or after the list.
* A null separator is the same as a blank String.
*
* @param array the array of values to join together
* @param separator the separator character to use
* @return the joined String
*/
public static String join(Object[] array, String separator) {
if (separator == null) {
separator = "";
}
int arraySize = array.length;
int bufSize = (arraySize == 0 ? 0 : (array[0].toString().length() +
separator.length()) * arraySize);
StringBuffer buf = new StringBuffer(bufSize);
for (int i = 0; i < arraySize; i++) {
if (i > 0) {
buf.append(separator);
}
buf.append(array[i]);
}
return buf.toString();
}
/**
* Joins the elements of the provided iterator into a single string
* containing the provided elements.
* No delimiter is added before or after the list.
* A null separator is the same as a blank String.
*
* @param iterator the iterator of values to join together
* @param separator the separator character to use
* @return the joined String
*/
public static String join(Iterator iterator, String separator) {
if (separator == null) {
separator = "";
}
StringBuffer buf = new StringBuffer(256); // Java default is 16, probably too small
while (iterator.hasNext()) {
buf.append(iterator.next());
if (iterator.hasNext()) {
buf.append(separator);
}
}
return buf.toString();
}
// Replacing
//--------------------------------------------------------------------------
/**
* Replace a string with another string inside a larger string, once.
*
* @see #replace(String text, String repl, String with, int max)
* @param text text to search and replace in
* @param repl String to search for
* @param with String to replace with
* @return the text with any replacements processed
*/
public static String replaceOnce(String text, String repl, String with) {
return replace(text, repl, with, 1);
}
/**
* Replace all occurances of a string within another string.
*
* @see #replace(String text, String repl, String with, int max)
* @param text text to search and replace in
* @param repl String to search for
* @param with String to replace with
* @return the text with any replacements processed
*/
public static String replace(String text, String repl, String with) {
return replace(text, repl, with, -1);
}
/**
* Replace a string with another string inside a larger string,
* for the first <code>max</code> values of the search string. A
* <code>null</code> reference is passed to this method is a
* no-op.
*
* @param text text to search and replace in
* @param repl String to search for
* @param with String to replace with
* @param max maximum number of values to replace, or
* <code>-1</code> if no maximum
* @return the text with any replacements processed
* @throws NullPointerException if repl is null
*/
public static String replace(String text, String repl, String with,
int max) {
if (text == null) {
return null;
}
StringBuffer buf = new StringBuffer(text.length());
int start = 0, end = 0;
while ((end = text.indexOf(repl, start)) != -1) {
buf.append(text.substring(start, end)).append(with);
start = end + repl.length();
if (--max == 0) {
break;
}
}
buf.append(text.substring(start));
return buf.toString();
}
/**
* Overlay a part of a string with another string.
*
* @param text String to do overlaying in
* @param overlay String to overlay
* @param start int to start overlaying at
* @param end int to stop overlaying before
* @return String with overlayed text
* @throws NullPointerException if text or overlay is null
*/
public static String overlayString(String text, String overlay, int start, int end) {
return new StringBuffer(start + overlay.length() + text.length() - end + 1)
.append(text.substring(0, start))
.append(overlay)
.append(text.substring(end))
.toString();
}
// Centering
//--------------------------------------------------------------------------
/**
* Center a string in a larger string of size n.
* Uses spaces as the value to buffer the string with.
* Equivalent to <code>center(str, size, "")</code>
*
* @param str String to center
* @param size int size of new String
* @return String containing centered String
* @throws NullPointerException if str is null
*/
public static String center(String str, int size) {
return center(str, size, " ");
}
/**
* Center a string in a larger string of size n.
* Uses a supplied String as the value to buffer the string with..
*
* @param str String to center
* @param size int size of new String
* @param delim String to buffer the new String with
* @return String containing centered String
* @throws NullPointerException if str or delim is null
* @throws ArithmeticException if delim is the empty string
*/
public static String center(String str, int size, String delim) {
int sz = str.length();
int p = size - sz;
if (p < 1) {
return str;
}
str = leftPad(str, sz + p / 2, delim);
str = rightPad(str, size, delim);
return str;
}
// Chomping
//--------------------------------------------------------------------------
/**
* Remove the last newline, and everything after it from a String.
*
* @param str String to chomp the newline from
* @return String without chomped newline
* @throws NullPointerException if str is null
*/
public static String chomp(String str) {
return chomp(str, "\n");
}
/**
* Remove the last value of a supplied String, and everything after it
* from a String.
*
* @param str String to chomp from
* @param sep String to chomp
* @return String without chomped ending
* @throws NullPointerException if str or sep is null
*/
public static String chomp(String str, String sep) {
int idx = str.lastIndexOf(sep);
if (idx != -1) {
return str.substring(0, idx);
} else {
return str;
}
}
/**
* Remove a newline if and only if it is at the end
* of the supplied string.
*
* @param str String to chomp from
* @return String without chomped ending
* @throws NullPointerException if str is null
*/
public static String chompLast(String str) {
return chompLast(str, "\n");
}
/**
* Remove a value if and only if the string ends with that value.
*
* @param str String to chomp from
* @param sep String to chomp
* @return String without chomped ending
* @throws NullPointerException if str or sep is null
*/
public static String chompLast(String str, String sep) {
if (str.length() == 0) {
return str;
}
String sub = str.substring(str.length() - sep.length());
if (sep.equals(sub)) {
return str.substring(0, str.length() - sep.length());
} else {
return str;
}
}
/**
* Remove everything and return the last value of a supplied String, and
* everything after it from a String.
*
* @param str String to chomp from
* @param sep String to chomp
* @return String chomped
* @throws NullPointerException if str or sep is null
*/
public static String getChomp(String str, String sep) {
int idx = str.lastIndexOf(sep);
if (idx == str.length() - sep.length()) {
return sep;
} else if (idx != -1) {
return str.substring(idx);
} else {
return "";
}
}
/**
* Remove the first value of a supplied String, and everything before it
* from a String.
*
* @param str String to chomp from
* @param sep String to chomp
* @return String without chomped beginning
* @throws NullPointerException if str or sep is null
*/
public static String prechomp(String str, String sep) {
int idx = str.indexOf(sep);
if (idx != -1) {
return str.substring(idx + sep.length());
} else {
return str;
}
}
/**
* Remove and return everything before the first value of a
* supplied String from another String.
*
* @param str String to chomp from
* @param sep String to chomp
* @return String prechomped
* @throws NullPointerException if str or sep is null
*/
public static String getPrechomp(String str, String sep) {
int idx = str.indexOf(sep);
if (idx != -1) {
return str.substring(0, idx + sep.length());
} else {
return "";
}
}
// Chopping
//--------------------------------------------------------------------------
/**
* Remove the last character from a String. If the String
* ends in \r\n, then remove both of them.
*
* @param str String to chop last character from
* @return String without last character
* @throws NullPointerException if str is null
*/
public static String chop(String str) {
if ("".equals(str)) {
return "";
}
if (str.length() == 1) {
return "";
}
int lastIdx = str.length() - 1;
String ret = str.substring(0, lastIdx);
char last = str.charAt(lastIdx);
if (last == '\n') {
if (ret.charAt(lastIdx - 1) == '\r') {
return ret.substring(0, lastIdx - 1);
}
}
return ret;
}
/**
* Remove \n from end of a String if it's there.
* If a \r precedes it, then remove that too.
*
* @param str String to chop a newline from
* @return String without newline
* @throws NullPointerException if str is null
*/
public static String chopNewline(String str) {
int lastIdx = str.length() - 1;
char last = str.charAt(lastIdx);
if (last == '\n') {
if (str.charAt(lastIdx - 1) == '\r') {
lastIdx--;
}
} else {
lastIdx++;
}
return str.substring(0, lastIdx);
}
// Conversion
//--------------------------------------------------------------------------
// spec 3.10.6
/**
* Escapes any values it finds into their String form.
* So a tab becomes the characters '\\' and 't'.
*
* @param str String to escape values in
*
* @return String with escaped values
* @throws NullPointerException if str is null
*/
public static String escape(String str) {
// improved with code from cybertiger@cyberiantiger.org
// unicode from him, and defaul for < 32's.
int sz = str.length();
StringBuffer buffer = new StringBuffer(2 * sz);
for (int i = 0; i < sz; i++) {
char ch = str.charAt(i);
// handle unicode
if (ch > 0xfff) {
buffer.append("\\u" + Integer.toHexString(ch));
} else if (ch > 0xff) {
buffer.append("\\u0" + Integer.toHexString(ch));
} else if (ch > 0x7f) {
buffer.append("\\u00" + Integer.toHexString(ch));
} else if (ch < 32) {
switch (ch) {
case '\b' :
buffer.append('\\');
buffer.append('b');
break;
case '\n' :
buffer.append('\\');
buffer.append('n');
break;
case '\t' :
buffer.append('\\');
buffer.append('t');
break;
case '\f' :
buffer.append('\\');
buffer.append('f');
break;
case '\r' :
buffer.append('\\');
buffer.append('r');
break;
default :
if (ch > 0xf) {
buffer.append("\\u00" + Integer.toHexString(ch));
} else {
buffer.append("\\u000" + Integer.toHexString(ch));
}
break;
}
} else {
switch (ch) {
case '\'' :
buffer.append('\\');
buffer.append('\'');
break;
case '"' :
buffer.append('\\');
buffer.append('"');
break;
case '\\' :
buffer.append('\\');
buffer.append('\\');
break;
default :
buffer.append(ch);
break;
}
}
}
return buffer.toString();
}
// Padding
//--------------------------------------------------------------------------
/**
* Repeat a string n times to form a new string.
*
* @param str String to repeat
* @param repeat int number of times to repeat
* @return String with repeated string
* @throws NegativeArraySizeException if repeat < 0
* @throws NullPointerException if str is null
*/
public static String repeat(String str, int repeat) {
StringBuffer buffer = new StringBuffer(repeat * str.length());
for (int i = 0; i < repeat; i++) {
buffer.append(str);
}
return buffer.toString();
}
/**
* Right pad a String with spaces. Pad to a size of n.
*
* @param str String to repeat
* @param size int number of times to repeat
* @return right padded String
* @throws NullPointerException if str is null
*/
public static String rightPad(String str, int size) {
return rightPad(str, size, " ");
}
/**
* Right pad a String with a specified string. Pad to a size of n.
*
* @param str String to pad out
* @param size int size to pad to
* @param delim String to pad with
* @return right padded String
* @throws NullPointerException if str or delim is null
* @throws ArithmeticException if delim is the empty string
*/
public static String rightPad(String str, int size, String delim) {
size = (size - str.length()) / delim.length();
if (size > 0) {
str += repeat(delim, size);
}
return str;
}
/**
* Left pad a String with spaces. Pad to a size of n.
*
* @param str String to pad out
* @param size int size to pad to
* @return left padded String
* @throws NullPointerException if str or delim is null
*/
public static String leftPad(String str, int size) {
return leftPad(str, size, " ");
}
/**
* Left pad a String with a specified string. Pad to a size of n.
*
* @param str String to pad out
* @param size int size to pad to
* @param delim String to pad with
* @return left padded String
* @throws NullPointerException if str or delim is null
* @throws ArithmeticException if delim is the empty string
*/
public static String leftPad(String str, int size, String delim) {
size = (size - str.length()) / delim.length();
if (size > 0) {
str = repeat(delim, size) + str;
}
return str;
}
// Stripping
//--------------------------------------------------------------------------
/**
* Remove whitespace from the front and back of a String.
*
* @param str the string to remove whitespace from
* @return the stripped string
*/
public static String strip(String str) {
return strip(str, null);
}
/**
* Remove a specified String from the front and back of a
* String. If Whitespace is wanted to be removed, used the
* strip(String) method.
*
* @param str the string to remove a string from
* @param delim the string to remove at start and end
* @return the stripped string
*/
public static String strip(String str, String delim) {
str = stripStart(str, delim);
return stripEnd(str, delim);
}
/**
* Strip whitespace from the front and back of every string
* in the array.
*
* @param strs the strings to remove whitespace from
* @return the stripped strings
*/
public static String[] stripAll(String[] strs) {
return stripAll(strs, null);
}
/**
* Strip the specified delimiter from the front and back of
* every String in the array.
*
* @param strs the strings to remove a string from
* @param delimiter the string to remove at start and end
* @return the stripped strings
*/
public static String[] stripAll(String[] strs, String delimiter) {
if ((strs == null) || (strs.length == 0)) {
return strs;
}
int sz = strs.length;
String[] newArr = new String[sz];
for (int i = 0; i < sz; i++) {
newArr[i] = strip(strs[i], delimiter);
}
return newArr;
}
/**
* Strip any of a supplied string from the end of a String..
* If the strip string is null, whitespace is stripped.
*
* @param str the string to remove characters from
* @param strip the string to remove
* @return the stripped string
*/
public static String stripEnd(String str, String strip) {
if (str == null) {
return null;
}
int end = str.length();
if (strip == null) {
while ((end != 0) && Character.isWhitespace(str.charAt(end - 1))) {
end--;
}
} else {
while ((end != 0) && (strip.indexOf(str.charAt(end - 1)) != -1)) {
end--;
}
}
return str.substring(0, end);
}
/**
* Strip any of a supplied string from the start of a String.
* If the strip string is null, whitespace is stripped.
*
* @param str the string to remove characters from
* @param strip the string to remove
* @return the stripped string
*/
public static String stripStart(String str, String strip) {
if (str == null) {
return null;
}
int start = 0;
int sz = str.length();
if (strip == null) {
while ((start != sz) && Character.isWhitespace(str.charAt(start))) {
start++;
}
} else {
while ((start != sz) && (strip.indexOf(str.charAt(start)) != -1)) {
start++;
}
}
return str.substring(start);
}
// Case conversion
//--------------------------------------------------------------------------
/**
* Convert a String to upper case, null string returns null.
*
* @param str the string to uppercase
* @return the upper cased string
*/
public static String upperCase(String str) {
if (str == null) {
return null;
}
return str.toUpperCase();
}
/**
* Convert a String to lower case, null string returns null.
*
* @param str the string to lowercase
* @return the lower cased string
*/
public static String lowerCase(String str) {
if (str == null) {
return null;
}
return str.toLowerCase();
}
/**
* Uncapitalise a string. That is, convert the first character into
* lower-case. Null is returned as null.
*
* @param str the string to uncapitalise
* @return uncapitalised string
*/
public static String uncapitalise(String str) {
if (str == null) {
return null;
}
if (str.length() == 0) {
return "";
}
return new StringBuffer(str.length())
.append(Character.toLowerCase(str.charAt(0)))
.append(str.substring(1))
.toString();
}
/**
* Capitalise a string. That is, convert the first character into
* title-case. Null is returned as null.
*
* @param str the string to capitalise
* @return capitalised string
*/
public static String capitalise(String str) {
if (str == null) {
return null;
}
if (str.length() == 0) {
return "";
}
return new StringBuffer(str.length())
.append(Character.toTitleCase(str.charAt(0)))
.append(str.substring(1))
.toString();
}
/**
* Swaps the case of String. Properly looks after
* making sure the start of words are Titlecase and not
* Uppercase. Null is returned as null.
*
* @param str the string to swap the case of
* @return the modified string
*/
public static String swapCase(String str) {
if (str == null) {
return null;
}
int sz = str.length();
StringBuffer buffer = new StringBuffer(sz);
boolean whitespace = false;
char ch = 0;
char tmp = 0;
for (int i = 0; i < sz; i++) {
ch = str.charAt(i);
if (Character.isUpperCase(ch)) {
tmp = Character.toLowerCase(ch);
} else if (Character.isTitleCase(ch)) {
tmp = Character.toLowerCase(ch);
} else if (Character.isLowerCase(ch)) {
if (whitespace) {
tmp = Character.toTitleCase(ch);
} else {
tmp = Character.toUpperCase(ch);
}
} else {
tmp = ch;
}
buffer.append(tmp);
whitespace = Character.isWhitespace(ch);
}
return buffer.toString();
}
/**
* Capitalise all the words in a string. Uses Character.isWhitespace
* as a separator between words. Null will return null.
*
* @param str the string to capitalise
* @return capitalised string
*/
public static String capitaliseAllWords(String str) {
if (str == null) {
return null;
}
int sz = str.length();
StringBuffer buffer = new StringBuffer(sz);
boolean space = true;
for (int i = 0; i < sz; i++) {
char ch = str.charAt(i);
if (Character.isWhitespace(ch)) {
buffer.append(ch);
space = true;
} else if (space) {
buffer.append(Character.toTitleCase(ch));
space = false;
} else {
buffer.append(ch);
}
}
return buffer.toString();
}
// Nested extraction
//--------------------------------------------------------------------------
/**
* Get the String that is nested in between two instances of the
* same String. If str is null, will return null
*
* @param str the string containing nested-string
* @param tag the string before and after nested-string
* @return the string that was nested, or null
* @throws NullPointerException if tag is null
*/
public static String getNestedString(String str, String tag) {
return getNestedString(str, tag, tag);
}
/**
* Get the string that is nested in between two strings.
*
* @param str the string containing nested-string
* @param open the string before nested-string
* @param close the string after nested-string
* @return the string that was nested, or null
* @throws NullPointerException if open or close is null
*/
public static String getNestedString(String str, String open, String close) {
if (str == null) {
return null;
}
int start = str.indexOf(open);
if (start != -1) {
int end = str.indexOf(close, start + open.length());
if (end != -1) {
return str.substring(start + open.length(), end);
}
}
return null;
}
/**
* How many times is the substring in the larger string.
* Null returns 0.
*
* @param str the string to check
* @param sub the substring to count
* @return the number of occurances, 0 if the string is null
* @throws NullPointerException if sub is null
*/
public static int countMatches(String str, String sub) {
if (str == null) {
return 0;
}
int count = 0;
int idx = 0;
while ((idx = str.indexOf(sub, idx)) != -1) {
count++;
idx += sub.length();
}
return count;
}
// Character Tests
//--------------------------------------------------------------------------
/**
* Checks if the string contains only unicode letters.
* Null will return false. The empty string will return true.
*
* @param str the string to check
* @return true if only contains letters, and is non-null
*/
public static boolean isAlpha(String str) {
if (str == null) {
return false;
}
int sz = str.length();
for (int i = 0; i < sz; i++) {
if (Character.isLetter(str.charAt(i)) == false) {
return false;
}
}
return true;
}
/**
* Checks if the string contains only unicode letters and space (' ').
* Null will return false. The empty string will return true.
*
* @param str the string to check
* @return true if only contains letters and space, and is non-null
*/
public static boolean isAlphaSpace(String str) {
if (str == null) {
return false;
}
int sz = str.length();
for (int i = 0; i < sz; i++) {
if ((Character.isLetter(str.charAt(i)) == false) &&
(str.charAt(i) != ' ')) {
return false;
}
}
return true;
}
/**
* Checks if the string contains only unicode letters or digits.
* Null will return false. The empty string will return true.
*
* @param str the string to check
* @return true if only contains letters or digits, and is non-null
*/
public static boolean isAlphanumeric(String str) {
if (str == null) {
return false;
}
int sz = str.length();
for (int i = 0; i < sz; i++) {
if (Character.isLetterOrDigit(str.charAt(i)) == false) {
return false;
}
}
return true;
}
/**
* Checks if the string contains only unicode letters, digits or space (' ').
* Null will return false. The empty string will return true.
*
* @param str the string to check
* @return true if only contains letters, digits or space, and is non-null
*/
public static boolean isAlphanumericSpace(String str) {
if (str == null) {
return false;
}
int sz = str.length();
for (int i = 0; i < sz; i++) {
if ((Character.isLetterOrDigit(str.charAt(i)) == false) &&
(str.charAt(i) != ' ')) {
return false;
}
}
return true;
}
/**
* Checks if the string contains only unicode digits.
* Null will return false. The empty string will return true.
*
* @param str the string to check
* @return true if only contains digits, and is non-null
*/
public static boolean isNumeric(String str) {
if (str == null) {
return false;
}
int sz = str.length();
for (int i = 0; i < sz; i++) {
if (Character.isDigit(str.charAt(i)) == false) {
return false;
}
}
return true;
}
/**
* Checks if the string contains only unicode digits or space (' ').
* Null will return false. The empty string will return true.
*
* @param str the string to check
* @return true if only contains digits or space, and is non-null
*/
public static boolean isNumericSpace(String str) {
if (str == null) {
return false;
}
int sz = str.length();
for (int i = 0; i < sz; i++) {
if ((Character.isDigit(str.charAt(i)) == false) &&
(str.charAt(i) != ' ')) {
return false;
}
}
return true;
}
// Defaults
//--------------------------------------------------------------------------
/**
* Return either the passed in String, or if it is null,
* then an empty String.
*
* @param str the string to check
* @return the passed in string, or blank if it was null
*/
public static String defaultString(String str) {
return defaultString(str, "");
}
/**
* Return either the passed in String, or if it is null,
* then a passed in default String.
*
* @param str the string to check
* @param defaultString the default string to return is str is null
* @return the passed in string, or the default if it was null
*/
public static String defaultString(String str, String defaultString) {
return (str == null) ? defaultString : str;
}
// Reversing
//--------------------------------------------------------------------------
/**
* Reverse a String, null string returns null.
*
* @param str the string to reverse
* @return the reversed string
*/
public static String reverse(String str) {
if (str == null) {
return null;
}
return new StringBuffer(str).reverse().toString();
}
/**
* Reverses a string that is delimited by a specific character.
* The strings between the delimiters are not reversed.
* Thus java.lang.String becomes String.lang.java (if the delimiter is '.').
*
* @param str the string to reverse
* @param delimiter the delimiter to use
* @return the reversed string
*/
public static String reverseDelimitedString(String str, String delimiter) {
// could implement manually, but simple way is to reuse other,
// probably slower, methods.
String[] strs = split(str, delimiter);
reverseArray(strs);
return join(strs, delimiter);
}
/**
* Reverses an array.
* TAKEN FROM CollectionsUtils.
* @param array the array to reverse
*/
private static void reverseArray(Object[] array) {
int i = 0;
int j = array.length - 1;
Object tmp;
while (j > i) {
tmp = array[j];
array[j] = array[i];
array[i] = tmp;
j--;
i++;
}
}
// Misc
//--------------------------------------------------------------------------
/**
* Find the Levenshtein distance between two strings.
* This is the number of changes needed to change one string into
* another. Where each change is a single character modification.
*
* This implemmentation of the levenshtein distance algorithm
* is from http://www.merriampark.com/ld.htm
*
* @param s the first String
* @param t the second String
* @return int result distance
* @throws NullPointerException if s or t is null
*/
public static int getLevenshteinDistance(String s, String t) {
int d[][]; // matrix
int n; // length of s
int m; // length of t
int i; // iterates through s
int j; // iterates through t
char s_i; // ith character of s
char t_j; // jth character of t
int cost; // cost
// Step 1
n = s.length();
m = t.length();
if (n == 0) {
return m;
}
if (m == 0) {
return n;
}
d = new int[n + 1][m + 1];
// Step 2
for (i = 0; i <= n; i++) {
d[i][0] = i;
}
for (j = 0; j <= m; j++) {
d[0][j] = j;
}
// Step 3
for (i = 1; i <= n; i++) {
s_i = s.charAt(i - 1);
// Step 4
for (j = 1; j <= m; j++) {
t_j = t.charAt(j - 1);
// Step 5
if (s_i == t_j) {
cost = 0;
} else {
cost = 1;
}
// Step 6
d[i][j] = NumberUtils.minimum(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + cost);
}
}
// Step 7
return d[n][m];
}
/**
* Checks if the String contains only certain chars.
*
* @param str the String to check
* @param valid an array of valid chars
* @return true if it only contains valid chars and is non-null
*/
public static boolean containsOnly(String str, char[] valid) {
if (str == null || valid == null) {
return false;
}
int strSize = str.length();
int validSize = valid.length;
for (int i = 0; i < strSize; i++) {
boolean contains = false;
for (int j = 0; j < validSize; j++) {
if (valid[j] == str.charAt(i)) {
contains = true;
break;
}
}
if (!contains) {
return false;
}
}
return true;
}
}
⏎ org/apache/commons/lang/StringUtils.java
⇒ Using commons-lang3.jar in Java Programs
⇐ commons-lang-2.6.jar - Apache Commons Lang
2017-04-15, ≈25🔥, 0💬
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