org.apache.commons.lang
Class CharSetUtils

java.lang.Object
  org.apache.commons.lang.CharSetUtils

public class CharSetUtils
extends Object

Operations on CharSets.

This class handles null input gracefully. An exception will not be thrown for a null input. Each method documents its behaviour in more detail.

#ThreadSafe#

Since:

1.0

Version:

$Id: CharSetUtils.java 1057072 2011-01-10 01:55:57Z niallp $

Author:

Apache Software Foundation, Phil Steitz, Gary Gregory

See Also:

CharSet

Constructor Summary

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

Method Summary

static int	count(String str, String set) Takes an argument in set-syntax, see evaluateSet, and returns the number of characters present in the specified string.
static int	count(String str, String[] set) Takes an argument in set-syntax, see evaluateSet, and returns the number of characters present in the specified string.
static String	delete(String str, String set) Takes an argument in set-syntax, see evaluateSet, and deletes any of characters present in the specified string.
static String	delete(String str, String[] set) Takes an argument in set-syntax, see evaluateSet, and deletes any of characters present in the specified string.
static CharSet	evaluateSet(String[] set) Deprecated. Use CharSet.getInstance(String[]). Method will be removed in Commons Lang 3.0.
static String	keep(String str, String set) Takes an argument in set-syntax, see evaluateSet, and keeps any of characters present in the specified string.
static String	keep(String str, String[] set) Takes an argument in set-syntax, see evaluateSet, and keeps any of characters present in the specified string.
static String	squeeze(String str, String set) Squeezes any repetitions of a character that is mentioned in the supplied set.
static String	squeeze(String str, String[] set) Squeezes any repetitions of a character that is mentioned in the supplied set.
static String	translate(String str, String searchChars, String replaceChars) Deprecated. Use StringUtils.replaceChars(String, String, String). Method will be removed in Commons Lang 3.0. NOTE: StringUtils#replaceChars behaves differently when 'searchChars' is longer than 'replaceChars'. CharSetUtils#translate will use the last char of the replacement string whereas StringUtils#replaceChars will delete

Methods inherited from class java.lang.Object

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

Constructor Detail

CharSetUtils

public CharSetUtils()

CharSetUtils instances should NOT be constructed in standard programming. Instead, the class should be used as CharSetUtils.evaluateSet(null);.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

evaluateSet

public static CharSet evaluateSet(String[] set)

Deprecated. Use CharSet.getInstance(String[]). Method will be removed in Commons Lang 3.0.

Creates a CharSet instance which allows a certain amount of set logic to be performed.

The syntax is:

• "aeio" which implies 'a','e',..
• "^e" implies not e.
• "ej-m" implies e,j->m. e,j,k,l,m.

 CharSetUtils.evaluateSet(null)    = null
 CharSetUtils.evaluateSet([])      = CharSet matching nothing
 CharSetUtils.evaluateSet(["a-e"]) = CharSet matching a,b,c,d,e
 

Parameters:

set - the set, may be null

Returns:

a CharSet instance, null if null input

squeeze

public static String squeeze(String str,
                             String set)

Squeezes any repetitions of a character that is mentioned in the supplied set.

 CharSetUtils.squeeze(null, *)        = null
 CharSetUtils.squeeze("", *)          = ""
 CharSetUtils.squeeze(*, null)        = *
 CharSetUtils.squeeze(*, "")          = *
 CharSetUtils.squeeze("hello", "k-p") = "helo"
 CharSetUtils.squeeze("hello", "a-e") = "hello"
 

Parameters:

str - the string to squeeze, may be null

set - the character set to use for manipulation, may be null

Returns:

modified String, null if null string input

See Also:

for set-syntax.

squeeze

public static String squeeze(String str,
                             String[] set)

Squeezes any repetitions of a character that is mentioned in the supplied set.

An example is:

• squeeze("hello", {"el"}) => "helo"

Parameters:

str - the string to squeeze, may be null

set - the character set to use for manipulation, may be null

Returns:

modified String, null if null string input

See Also:

for set-syntax.

count

public static int count(String str,
                        String set)

Takes an argument in set-syntax, see evaluateSet, and returns the number of characters present in the specified string.

 CharSetUtils.count(null, *)        = 0
 CharSetUtils.count("", *)          = 0
 CharSetUtils.count(*, null)        = 0
 CharSetUtils.count(*, "")          = 0
 CharSetUtils.count("hello", "k-p") = 3
 CharSetUtils.count("hello", "a-e") = 1
 

Parameters:

str - String to count characters in, may be null

set - String set of characters to count, may be null

Returns:

character count, zero if null string input

See Also:

for set-syntax.

count

public static int count(String str,
                        String[] set)

Takes an argument in set-syntax, see evaluateSet, and returns the number of characters present in the specified string.

An example would be:

• count("hello", {"c-f", "o"}) returns 2.

Parameters:

str - String to count characters in, may be null

set - String[] set of characters to count, may be null

Returns:

character count, zero if null string input

See Also:

for set-syntax.

keep

public static String keep(String str,
                          String set)

Takes an argument in set-syntax, see evaluateSet, and keeps any of characters present in the specified string.

 CharSetUtils.keep(null, *)        = null
 CharSetUtils.keep("", *)          = ""
 CharSetUtils.keep(*, null)        = ""
 CharSetUtils.keep(*, "")          = ""
 CharSetUtils.keep("hello", "hl")  = "hll"
 CharSetUtils.keep("hello", "le")  = "ell"
 

Parameters:

str - String to keep characters from, may be null

set - String set of characters to keep, may be null

Returns:

modified String, null if null string input

Since:

2.0

See Also:

for set-syntax.

keep

public static String keep(String str,
                          String[] set)

Takes an argument in set-syntax, see evaluateSet, and keeps any of characters present in the specified string.

An example would be:

• keep("hello", {"c-f", "o"}) returns "eo"

Parameters:

str - String to keep characters from, may be null

set - String[] set of characters to keep, may be null

Returns:

modified String, null if null string input

Since:

2.0

See Also:

for set-syntax.

delete

public static String delete(String str,
                            String set)

Takes an argument in set-syntax, see evaluateSet, and deletes any of characters present in the specified string.

 CharSetUtils.delete(null, *)        = null
 CharSetUtils.delete("", *)          = ""
 CharSetUtils.delete(*, null)        = *
 CharSetUtils.delete(*, "")          = *
 CharSetUtils.delete("hello", "hl")  = "eo"
 CharSetUtils.delete("hello", "le")  = "ho"
 

Parameters:

str - String to delete characters from, may be null

set - String set of characters to delete, may be null

Returns:

modified String, null if null string input

See Also:

for set-syntax.

delete

public static String delete(String str,
                            String[] set)

Takes an argument in set-syntax, see evaluateSet, and deletes any of characters present in the specified string.

An example would be:

• delete("hello", {"c-f", "o"}) returns "hll"

Parameters:

str - String to delete characters from, may be null

set - String[] set of characters to delete, may be null

Returns:

modified String, null if null string input

See Also:

for set-syntax.

translate

public static String translate(String str,
                               String searchChars,
                               String replaceChars)

Deprecated. Use StringUtils.replaceChars(String, String, String). Method will be removed in Commons Lang 3.0. NOTE: StringUtils#replaceChars behaves differently when 'searchChars' is longer than 'replaceChars'. CharSetUtils#translate will use the last char of the replacement string whereas StringUtils#replaceChars will delete

Translate characters in a String. This is a multi character search and replace routine.

An example is:

• translate("hello", "ho", "jy") => jelly

If the length of characters to search for is greater than the length of characters to replace, then the last character is used.

 CharSetUtils.translate(null, *, *) = null
 CharSetUtils.translate("", *, *)   = ""
 

Parameters:

str - String to replace characters in, may be null

searchChars - a set of characters to search for, must not be null

replaceChars - a set of characters to replace, must not be null or empty ("")

Returns:

translated String, null if null string input

Throws:

NullPointerException - if searchChars or replaceChars is null

ArrayIndexOutOfBoundsException - if replaceChars is empty ("")