org.apache.commons.lang
Class StringUtils

java.lang.Object
  |
  +--org.apache.commons.lang.StringUtils

public class StringUtils

extends java.lang.Object

Common String manipulation routines.

Originally from Turbine and the GenerationJavaCore library.

Version:

$Id: StringUtils.java,v 1.18.2.1 2002/11/23 01:06:56 bayard Exp $

Author:

Jon S. Stevens, Daniel Rall, Greg Coladonato, Henri Yandell, Ed Korthof, Stephen Colebourne,

Constructor Summary

StringUtils()
StringUtils instances should NOT be constructed in standard programming.

Method Summary

static java.lang.String	capitalise(java.lang.String str) Capitalise a string.
static java.lang.String	capitaliseAllWords(java.lang.String str) Capitalise all the words in a string.
static java.lang.String	center(java.lang.String str, int size) Center a string in a larger string of size n.
static java.lang.String	center(java.lang.String str, int size, java.lang.String delim) Center a string in a larger string of size n.
static java.lang.String	chomp(java.lang.String str) Remove the last newline, and everything after it from a String.
static java.lang.String	chomp(java.lang.String str, java.lang.String sep) Remove the last value of a supplied String, and everything after it from a String.
static java.lang.String	chompLast(java.lang.String str) Remove a newline if and only if it is at the end of the supplied string.
static java.lang.String	chompLast(java.lang.String str, java.lang.String sep) Remove a value if and only if the string ends with that value.
static java.lang.String	chop(java.lang.String str) Remove the last character from a String.
static java.lang.String	chopNewline(java.lang.String str) Remove \n from end of a String if it's there.
static java.lang.String	clean(java.lang.String str) Removes control characters, including whitespace, from both ends of this string, handling null by returning an empty string.
static java.lang.String	concatenate(java.lang.Object[] array) Concatenates elements of an array into a single string.
static boolean	containsOnly(java.lang.String str, char[] valid) Checks if the String contains only certain chars.
static int	countMatches(java.lang.String str, java.lang.String sub) How many times is the substring in the larger string.
static java.lang.String	defaultString(java.lang.String str) Return either the passed in String, or if it is null, then an empty String.
static java.lang.String	defaultString(java.lang.String str, java.lang.String defaultString) Return either the passed in String, or if it is null, then a passed in default String.
static java.lang.String	deleteSpaces(java.lang.String str) Deletes all 'space' characters from a String.
static java.lang.String	deleteWhitespace(java.lang.String str) Deletes all whitespace from a String.
static boolean	equals(java.lang.String str1, java.lang.String str2) Compares two Strings, returning true if they are equal.
static boolean	equalsIgnoreCase(java.lang.String str1, java.lang.String str2) Compares two Strings, returning true if they are equal ignoring case.
static java.lang.String	escape(java.lang.String str) Escapes any values it finds into their String form.
static java.lang.String	getChomp(java.lang.String str, java.lang.String sep) Remove everything and return the last value of a supplied String, and everything after it from a String.
static int	getLevenshteinDistance(java.lang.String s, java.lang.String t) Find the Levenshtein distance between two strings.
static java.lang.String	getNestedString(java.lang.String str, java.lang.String tag) Get the String that is nested in between two instances of the same String.
static java.lang.String	getNestedString(java.lang.String str, java.lang.String open, java.lang.String close) Get the string that is nested in between two strings.
static java.lang.String	getPrechomp(java.lang.String str, java.lang.String sep) Remove and return everything before the first value of a supplied String from another String.
static int	indexOfAny(java.lang.String str, java.lang.String[] searchStrs) Find the earliest index of any of a set of potential substrings.
static boolean	isAlpha(java.lang.String str) Checks if the string contains only unicode letters.
static boolean	isAlphanumeric(java.lang.String str) Checks if the string contains only unicode letters or digits.
static boolean	isAlphanumericSpace(java.lang.String str) Checks if the string contains only unicode letters, digits or space (' ').
static boolean	isAlphaSpace(java.lang.String str) Checks if the string contains only unicode letters and space (' ').
static boolean	isEmpty(java.lang.String str) Checks if a (trimmed) String is null or empty.
static boolean	isNotEmpty(java.lang.String str) Checks if a String is non null and is not empty (length > 0).
static boolean	isNumeric(java.lang.String str) Checks if the string contains only unicode digits.
static boolean	isNumericSpace(java.lang.String str) Checks if the string contains only unicode digits or space (' ').
static java.lang.String	join(java.util.Iterator iterator, java.lang.String separator) Joins the elements of the provided iterator into a single string containing the provided elements.
static java.lang.String	join(java.lang.Object[] array, java.lang.String separator) Joins the elements of the provided array into a single string containing the provided list of elements.
static int	lastIndexOfAny(java.lang.String str, java.lang.String[] searchStrs) Find the latest index of any of a set of potential substrings.
static java.lang.String	left(java.lang.String str, int len) Gets the leftmost n characters of a string.
static java.lang.String	leftPad(java.lang.String str, int size) Left pad a String with spaces.
static java.lang.String	leftPad(java.lang.String str, int size, java.lang.String delim) Left pad a String with a specified string.
static java.lang.String	lowerCase(java.lang.String str) Convert a String to lower case, null string returns null.
static java.lang.String	mid(java.lang.String str, int pos, int len) Gets n characters from the middle of a string.
static java.lang.String	overlayString(java.lang.String text, java.lang.String overlay, int start, int end) Overlay a part of a string with another string.
static java.lang.String	prechomp(java.lang.String str, java.lang.String sep) Remove the first value of a supplied String, and everything before it from a String.
static java.lang.String	repeat(java.lang.String str, int repeat) Repeat a string n times to form a new string.
static java.lang.String	replace(java.lang.String text, java.lang.String repl, java.lang.String with) Replace all occurances of a string within another string.
static java.lang.String	replace(java.lang.String text, java.lang.String repl, java.lang.String with, int max) Replace a string with another string inside a larger string, for the first max values of the search string.
static java.lang.String	replaceOnce(java.lang.String text, java.lang.String repl, java.lang.String with) Replace a string with another string inside a larger string, once.
static java.lang.String	reverse(java.lang.String str) Reverse a String, null string returns null.
private static void	reverseArray(java.lang.Object[] array) Reverses an array.
static java.lang.String	reverseDelimitedString(java.lang.String str, java.lang.String delimiter) Reverses a string that is delimited by a specific character.
static java.lang.String	right(java.lang.String str, int len) Gets the rightmost n characters of a string.
static java.lang.String	rightPad(java.lang.String str, int size) Right pad a String with spaces.
static java.lang.String	rightPad(java.lang.String str, int size, java.lang.String delim) Right pad a String with a specified string.
static java.lang.String[]	split(java.lang.String str) Splits the provided text into a list, using whitespace as the separator.
static java.lang.String[]	split(java.lang.String text, java.lang.String separator)
static java.lang.String[]	split(java.lang.String str, java.lang.String separator, int max) Splits the provided text into a list, based on a given separator.
static java.lang.String	strip(java.lang.String str) Remove whitespace from the front and back of a String.
static java.lang.String	strip(java.lang.String str, java.lang.String delim) Remove a specified String from the front and back of a String.
static java.lang.String[]	stripAll(java.lang.String[] strs) Strip whitespace from the front and back of every string in the array.
static java.lang.String[]	stripAll(java.lang.String[] strs, java.lang.String delimiter) Strip the specified delimiter from the front and back of every String in the array.
static java.lang.String	stripEnd(java.lang.String str, java.lang.String strip) Strip any of a supplied string from the end of a String..
static java.lang.String	stripStart(java.lang.String str, java.lang.String strip) Strip any of a supplied string from the start of a String.
static java.lang.String	substring(java.lang.String str, int start) Gets a substring of the specified string avoiding exceptions.
static java.lang.String	substring(java.lang.String str, int start, int end) Gets a substring of the specified string avoiding exceptions.
static java.lang.String	swapCase(java.lang.String str) Swaps the case of String.
static java.lang.String	trim(java.lang.String str) Removes control characters, including whitespace, from both ends of this string, handling null by returning null.
static java.lang.String	uncapitalise(java.lang.String str) Uncapitalise a string.
static java.lang.String	upperCase(java.lang.String str) Convert a String to upper case, null string returns null.

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Constructor Detail

StringUtils

public StringUtils()

StringUtils instances should NOT be constructed in standard programming. Instead, the class should be used as StringUtils.trim(" foo ");. This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

clean

public static java.lang.String clean(java.lang.String str)

Removes control characters, including whitespace, from both ends of this string, handling null by returning an empty string.

Parameters:

str - the string to check

Returns:

the trimmed text (never null)

See Also:

String.trim()

trim

public static java.lang.String trim(java.lang.String str)

Removes control characters, including whitespace, from both ends of this string, handling null by returning null.

Parameters:

str - the string to check

Returns:

the trimmed text (or null)

See Also:

String.trim()

deleteSpaces

public static java.lang.String deleteSpaces(java.lang.String str)

Deletes all 'space' characters from a String. Spaces are defined as {' ', '\t', '\r', '\n', '\b'} in line with the deprecated Character.isSpace

Parameters:

str - String target to delete spaces from

Returns:

the text without spaces

Throws:

NullPointerException -

deleteWhitespace

public static java.lang.String deleteWhitespace(java.lang.String str)

Deletes all whitespace from a String. Whitespace is defined by Character.isWhitespace

Parameters:

str - String target to delete whitespace from

Returns:

the text without whitespace

Throws:

NullPointerException -

isNotEmpty

public static boolean isNotEmpty(java.lang.String str)

Checks if a String is non null and is not empty (length > 0).

Parameters:

str - the string to check

Returns:

true if the String is non-null, and not length zero

isEmpty

public static boolean isEmpty(java.lang.String str)

Checks if a (trimmed) String is null or empty.

Parameters:

str - the string to check

Returns:

true if the String is null, or length zero once trimmed

equals

public static boolean equals(java.lang.String str1,
                             java.lang.String str2)

Compares two Strings, returning true if they are equal. Nulls are handled without exceptions. Two null references are considered equal. Comparison is case sensitive.

Parameters:

str1 - the first string

str2 - the second string

Returns:

true if the Strings are equal, case sensitive, or both null

See Also:

String.equals(Object)

equalsIgnoreCase

public static boolean equalsIgnoreCase(java.lang.String str1,
                                       java.lang.String str2)

Compares two Strings, returning true if they are equal ignoring case. Nulls are handled without exceptions. Two null references are considered equal. Comparison is case insensitive.

Parameters:

str1 - the first string

str2 - the second string

Returns:

true if the Strings are equal, case insensitive, or both null

See Also:

String.equalsIgnoreCase(String)

indexOfAny

public static int indexOfAny(java.lang.String str,
                             java.lang.String[] searchStrs)

Find the earliest index of any of a set of potential substrings. Null string will return -1.

Parameters:

str - the string to check

searchStrs - the strings to search for

Returns:

the earliest index of any of the strings

Throws:

NullPointerException - if any of searchStrs[i] is null

lastIndexOfAny

public static int lastIndexOfAny(java.lang.String str,
                                 java.lang.String[] searchStrs)

Find the latest index of any of a set of potential substrings. Null string will return -1.

Parameters:

str - the string to check

searchStrs - the strings to search for

Returns:

the last index of any of the strings

Throws:

NullPointerException - if any of searchStrs[i] is null

substring

public static java.lang.String substring(java.lang.String str,
                                         int start)

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.

Parameters:

str - the string to get the substring from

start - the position to start from, negative means count back from the end of the string by this many characters

Returns:

substring from start position

substring

public static java.lang.String substring(java.lang.String str,
                                         int start,
                                         int end)

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.

Parameters:

str - the string to get the substring from

start - the position to start from, negative means count back from the end of the string by this many characters

end - the position to end at (exclusive), negative means count back from the end of the string by this many characters

Returns:

substring from start position to end positon

left

public static java.lang.String left(java.lang.String str,
                                    int len)

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.

Parameters:

str - the string to get the leftmost characters from

len - the length of the required string

Returns:

the leftmost characters

Throws:

java.lang.IllegalArgumentException - if len is less than zero

right

public static java.lang.String right(java.lang.String str,
                                     int 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.

Parameters:

str - the string to get the rightmost characters from

len - the length of the required string

Returns:

the leftmost characters

Throws:

java.lang.IllegalArgumentException - if len is less than zero

mid

public static java.lang.String mid(java.lang.String str,
                                   int pos,
                                   int 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.

Parameters:

str - the string to get the characters from

pos - the position to start from

len - the length of the required string

Returns:

the leftmost characters

Throws:

IndexOutOfBoundsException - if pos is out of bounds

java.lang.IllegalArgumentException - if len is less than zero

split

public static java.lang.String[] split(java.lang.String str)

Splits the provided text into a list, using whitespace as the separator. The separator is not included in the returned String array.

Parameters:

str - the string to parse

Returns:

an array of parsed Strings

split

public static java.lang.String[] split(java.lang.String text,
                                       java.lang.String separator)

See Also:

split(String, String, int)

split

public static java.lang.String[] split(java.lang.String str,
                                       java.lang.String separator,
                                       int max)

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.

This is useful for quickly splitting a string directly into an array of tokens, instead of an enumeration of tokens (as StringTokenizer does).

Parameters:

str - The string to parse.

separator - Characters used as the delimiters. If null, splits on whitespace.

max - The maximum number of elements to include in the list. A zero or negative value implies no limit.

Returns:

an array of parsed Strings

concatenate

public static java.lang.String concatenate(java.lang.Object[] array)

Concatenates elements of an array into a single string. The difference from join is that concatenate has no delimiter.

Parameters:

array - the array of values to concatenate.

Returns:

the concatenated string.

join

public static java.lang.String join(java.lang.Object[] array,
                                    java.lang.String separator)

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.

Parameters:

array - the array of values to join together

separator - the separator character to use

Returns:

the joined String

join

public static java.lang.String join(java.util.Iterator iterator,
                                    java.lang.String separator)

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.

Parameters:

iterator - the iterator of values to join together

separator - the separator character to use

Returns:

the joined String

replaceOnce

public static java.lang.String replaceOnce(java.lang.String text,
                                           java.lang.String repl,
                                           java.lang.String with)

Replace a string with another string inside a larger string, once.

Parameters:

text - text to search and replace in

repl - String to search for

with - String to replace with

Returns:

the text with any replacements processed

See Also:

replace(String text, String repl, String with, int max)

replace

public static java.lang.String replace(java.lang.String text,
                                       java.lang.String repl,
                                       java.lang.String with)

Replace all occurances of a string within another string.

Parameters:

text - text to search and replace in

repl - String to search for

with - String to replace with

Returns:

the text with any replacements processed

See Also:

replace(String text, String repl, String with, int max)

replace

public static java.lang.String replace(java.lang.String text,
                                       java.lang.String repl,
                                       java.lang.String with,
                                       int max)

Replace a string with another string inside a larger string, for the first max values of the search string. A null reference is passed to this method is a no-op.

Parameters:

text - text to search and replace in

repl - String to search for

with - String to replace with

max - maximum number of values to replace, or -1 if no maximum

Returns:

the text with any replacements processed

Throws:

NullPointerException - if repl is null

overlayString

public static java.lang.String overlayString(java.lang.String text,
                                             java.lang.String overlay,
                                             int start,
                                             int end)

Overlay a part of a string with another string.

Parameters:

text - String to do overlaying in

overlay - String to overlay

start - int to start overlaying at

end - int to stop overlaying before

Returns:

String with overlayed text

Throws:

NullPointerException - if text or overlay is null

center

public static java.lang.String center(java.lang.String str,
                                      int size)

Center a string in a larger string of size n. Uses spaces as the value to buffer the string with. Equivalent to center(str, size, "")

Parameters:

str - String to center

size - int size of new String

Returns:

String containing centered String

Throws:

NullPointerException - if str is null

center

public static java.lang.String center(java.lang.String str,
                                      int size,
                                      java.lang.String delim)

Center a string in a larger string of size n. Uses a supplied String as the value to buffer the string with..

Parameters:

str - String to center

size - int size of new String

delim - String to buffer the new String with

Returns:

String containing centered String

Throws:

NullPointerException - if str or delim is null

ArithmeticException - if delim is the empty string

chomp

public static java.lang.String chomp(java.lang.String str)

Remove the last newline, and everything after it from a String.

Parameters:

str - String to chomp the newline from

Returns:

String without chomped newline

Throws:

NullPointerException - if str is null

chomp

public static java.lang.String chomp(java.lang.String str,
                                     java.lang.String sep)

Remove the last value of a supplied String, and everything after it from a String.

Parameters:

str - String to chomp from

sep - String to chomp

Returns:

String without chomped ending

Throws:

NullPointerException - if str or sep is null

chompLast

public static java.lang.String chompLast(java.lang.String str)

Remove a newline if and only if it is at the end of the supplied string.

Parameters:

str - String to chomp from

Returns:

String without chomped ending

Throws:

NullPointerException - if str is null

chompLast

public static java.lang.String chompLast(java.lang.String str,
                                         java.lang.String sep)

Remove a value if and only if the string ends with that value.

Parameters:

str - String to chomp from

sep - String to chomp

Returns:

String without chomped ending

Throws:

NullPointerException - if str or sep is null

getChomp

public static java.lang.String getChomp(java.lang.String str,
                                        java.lang.String sep)

Remove everything and return the last value of a supplied String, and everything after it from a String.

Parameters:

str - String to chomp from

sep - String to chomp

Returns:

String chomped

Throws:

NullPointerException - if str or sep is null

prechomp

public static java.lang.String prechomp(java.lang.String str,
                                        java.lang.String sep)

Remove the first value of a supplied String, and everything before it from a String.

Parameters:

str - String to chomp from

sep - String to chomp

Returns:

String without chomped beginning

Throws:

NullPointerException - if str or sep is null

getPrechomp

public static java.lang.String getPrechomp(java.lang.String str,
                                           java.lang.String sep)

Remove and return everything before the first value of a supplied String from another String.

Parameters:

str - String to chomp from

sep - String to chomp

Returns:

String prechomped

Throws:

NullPointerException - if str or sep is null

chop

public static java.lang.String chop(java.lang.String str)

Remove the last character from a String. If the String ends in \r\n, then remove both of them.

Parameters:

str - String to chop last character from

Returns:

String without last character

Throws:

NullPointerException - if str is null

chopNewline

public static java.lang.String chopNewline(java.lang.String str)

Remove \n from end of a String if it's there. If a \r precedes it, then remove that too.

Parameters:

str - String to chop a newline from

Returns:

String without newline

Throws:

NullPointerException - if str is null

escape

public static java.lang.String escape(java.lang.String str)

Escapes any values it finds into their String form. So a tab becomes the characters '\\' and 't'.

Parameters:

str - String to escape values in

Returns:

String with escaped values

Throws:

NullPointerException - if str is null

repeat

public static java.lang.String repeat(java.lang.String str,
                                      int repeat)

Repeat a string n times to form a new string.

Parameters:

str - String to repeat

repeat - int number of times to repeat

Returns:

String with repeated string

Throws:

NegativeArraySizeException - if repeat < 0

NullPointerException - if str is null

rightPad

public static java.lang.String rightPad(java.lang.String str,
                                        int size)

Right pad a String with spaces. Pad to a size of n.

Parameters:

str - String to repeat

size - int number of times to repeat

Returns:

right padded String

Throws:

NullPointerException - if str is null

rightPad

public static java.lang.String rightPad(java.lang.String str,
                                        int size,
                                        java.lang.String delim)

Right pad a String with a specified string. Pad to a size of n.

Parameters:

str - String to pad out

size - int size to pad to

delim - String to pad with

Returns:

right padded String

Throws:

NullPointerException - if str or delim is null

ArithmeticException - if delim is the empty string

leftPad

public static java.lang.String leftPad(java.lang.String str,
                                       int size)

Left pad a String with spaces. Pad to a size of n.

Parameters:

str - String to pad out

size - int size to pad to

Returns:

left padded String

Throws:

NullPointerException - if str or delim is null

leftPad

public static java.lang.String leftPad(java.lang.String str,
                                       int size,
                                       java.lang.String delim)

Left pad a String with a specified string. Pad to a size of n.

Parameters:

str - String to pad out

size - int size to pad to

delim - String to pad with

Returns:

left padded String

Throws:

NullPointerException - if str or delim is null

ArithmeticException - if delim is the empty string

strip

public static java.lang.String strip(java.lang.String str)

Remove whitespace from the front and back of a String.

Parameters:

str - the string to remove whitespace from

Returns:

the stripped string

strip

public static java.lang.String strip(java.lang.String str,
                                     java.lang.String delim)

Remove a specified String from the front and back of a String. If Whitespace is wanted to be removed, used the strip(String) method.

Parameters:

str - the string to remove a string from

delim - the string to remove at start and end

Returns:

the stripped string

stripAll

public static java.lang.String[] stripAll(java.lang.String[] strs)

Strip whitespace from the front and back of every string in the array.

Parameters:

strs - the strings to remove whitespace from

Returns:

the stripped strings

stripAll

public static java.lang.String[] stripAll(java.lang.String[] strs,
                                          java.lang.String delimiter)

Strip the specified delimiter from the front and back of every String in the array.

Parameters:

strs - the strings to remove a string from

delimiter - the string to remove at start and end

Returns:

the stripped strings

stripEnd

public static java.lang.String stripEnd(java.lang.String str,
                                        java.lang.String strip)

Strip any of a supplied string from the end of a String.. If the strip string is null, whitespace is stripped.

Parameters:

str - the string to remove characters from

strip - the string to remove

Returns:

the stripped string

stripStart

public static java.lang.String stripStart(java.lang.String str,
                                          java.lang.String strip)

Strip any of a supplied string from the start of a String. If the strip string is null, whitespace is stripped.

Parameters:

str - the string to remove characters from

strip - the string to remove

Returns:

the stripped string

upperCase

public static java.lang.String upperCase(java.lang.String str)

Convert a String to upper case, null string returns null.

Parameters:

str - the string to uppercase

Returns:

the upper cased string

lowerCase

public static java.lang.String lowerCase(java.lang.String str)

Convert a String to lower case, null string returns null.

Parameters:

str - the string to lowercase

Returns:

the lower cased string

uncapitalise

public static java.lang.String uncapitalise(java.lang.String str)

Uncapitalise a string. That is, convert the first character into lower-case. Null is returned as null.

Parameters:

str - the string to uncapitalise

Returns:

uncapitalised string

capitalise

public static java.lang.String capitalise(java.lang.String str)

Capitalise a string. That is, convert the first character into title-case. Null is returned as null.

Parameters:

str - the string to capitalise

Returns:

capitalised string

swapCase

public static java.lang.String swapCase(java.lang.String str)

Swaps the case of String. Properly looks after making sure the start of words are Titlecase and not Uppercase. Null is returned as null.

Parameters:

str - the string to swap the case of

Returns:

the modified string

capitaliseAllWords

public static java.lang.String capitaliseAllWords(java.lang.String str)

Capitalise all the words in a string. Uses Character.isWhitespace as a separator between words. Null will return null.

Parameters:

str - the string to capitalise

Returns:

capitalised string

getNestedString

public static java.lang.String getNestedString(java.lang.String str,
                                               java.lang.String tag)

Get the String that is nested in between two instances of the same String. If str is null, will return null

Parameters:

str - the string containing nested-string

tag - the string before and after nested-string

Returns:

the string that was nested, or null

Throws:

NullPointerException - if tag is null

getNestedString

public static java.lang.String getNestedString(java.lang.String str,
                                               java.lang.String open,
                                               java.lang.String close)

Get the string that is nested in between two strings.

Parameters:

str - the string containing nested-string

open - the string before nested-string

close - the string after nested-string

Returns:

the string that was nested, or null

Throws:

NullPointerException - if open or close is null

countMatches

public static int countMatches(java.lang.String str,
                               java.lang.String sub)

How many times is the substring in the larger string. Null returns 0.

Parameters:

str - the string to check

sub - the substring to count

Returns:

the number of occurances, 0 if the string is null

Throws:

NullPointerException - if sub is null

isAlpha

public static boolean isAlpha(java.lang.String str)

Checks if the string contains only unicode letters. Null will return false. The empty string will return true.

Parameters:

str - the string to check

Returns:

true if only contains letters, and is non-null

isAlphaSpace

public static boolean isAlphaSpace(java.lang.String str)

Checks if the string contains only unicode letters and space (' '). Null will return false. The empty string will return true.

Parameters:

str - the string to check

Returns:

true if only contains letters and space, and is non-null

isAlphanumeric

public static boolean isAlphanumeric(java.lang.String str)

Checks if the string contains only unicode letters or digits. Null will return false. The empty string will return true.

Parameters:

str - the string to check

Returns:

true if only contains letters or digits, and is non-null

isAlphanumericSpace

public static boolean isAlphanumericSpace(java.lang.String str)

Checks if the string contains only unicode letters, digits or space (' '). Null will return false. The empty string will return true.

Parameters:

str - the string to check

Returns:

true if only contains letters, digits or space, and is non-null

isNumeric

public static boolean isNumeric(java.lang.String str)

Checks if the string contains only unicode digits. Null will return false. The empty string will return true.

Parameters:

str - the string to check

Returns:

true if only contains digits, and is non-null

isNumericSpace

public static boolean isNumericSpace(java.lang.String str)

Checks if the string contains only unicode digits or space (' '). Null will return false. The empty string will return true.

Parameters:

str - the string to check

Returns:

true if only contains digits or space, and is non-null

defaultString

public static java.lang.String defaultString(java.lang.String str)

Return either the passed in String, or if it is null, then an empty String.

Parameters:

str - the string to check

Returns:

the passed in string, or blank if it was null

defaultString

public static java.lang.String defaultString(java.lang.String str,
                                             java.lang.String defaultString)

Return either the passed in String, or if it is null, then a passed in default String.

Parameters:

str - the string to check

defaultString - the default string to return is str is null

Returns:

the passed in string, or the default if it was null

reverse

public static java.lang.String reverse(java.lang.String str)

Reverse a String, null string returns null.

Parameters:

str - the string to reverse

Returns:

the reversed string

reverseDelimitedString

public static java.lang.String reverseDelimitedString(java.lang.String str,
                                                      java.lang.String delimiter)

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 '.').

Parameters:

str - the string to reverse

delimiter - the delimiter to use

Returns:

the reversed string

reverseArray

private static void reverseArray(java.lang.Object[] array)

Reverses an array. TAKEN FROM CollectionsUtils.

Parameters:

array - the array to reverse

getLevenshteinDistance

public static int getLevenshteinDistance(java.lang.String s,
                                         java.lang.String t)

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

Parameters:

s - the first String

t - the second String

Returns:

int result distance

Throws:

NullPointerException - if s or t is null

containsOnly

public static boolean containsOnly(java.lang.String str,
                                   char[] valid)

Checks if the String contains only certain chars.

Parameters:

str - the String to check

valid - an array of valid chars

Returns:

true if it only contains valid chars and is non-null