StringUtils (jOOQ 2.2.0 API)

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org.jooq.tools
Class StringUtils

java.lang.Object
  org.jooq.tools.StringUtils

public final class StringUtils
extends Object
extends Object

Operations on String that are null safe.

IsEmpty/IsBlank - checks if a String contains text
Trim/Strip - removes leading and trailing whitespace
Equals - compares two strings null-safe
startsWith - check if a String starts with a prefix null-safe
endsWith - check if a String ends with a suffix null-safe
IndexOf/LastIndexOf/Contains - null-safe index-of checks
IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut - index-of any of a set of Strings
ContainsOnly/ContainsNone/ContainsAny - does String contains only/none/any of these characters
Substring/Left/Right/Mid - null-safe substring extractions
SubstringBefore/SubstringAfter/SubstringBetween - substring extraction relative to other strings
Split/Join - splits a String into an array of substrings and vice versa
Remove/Delete - removes part of a String
Replace/Overlay - Searches a String and replaces one String with another
Chomp/Chop - removes the last part of a String
LeftPad/RightPad/Center/Repeat - pads a String
UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize - changes the case of a String
CountMatches - counts the number of occurrences of one String in another
IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable - checks the characters in a String
DefaultString - protects against a null input String
Reverse/ReverseDelimited - reverses a String
Abbreviate - abbreviates a string using ellipsis
Difference - compares Strings and reports on their differences
LevensteinDistance - the number of changes needed to change one String into another

The StringUtils class defines certain words related to String handling.

null - null
empty - a zero-length string ("")
space - the space character (' ', char 32)
whitespace - the characters defined by Character.isWhitespace(char)
trim - the characters <= 32 as in String.trim()

StringUtils handles null input Strings quietly. That is to say that a null input will return null. Where a boolean or int is being returned details vary by method.

A side effect of the null handling is that a NullPointerException should be considered a bug in StringUtils (except for deprecated methods).

Methods in this class give sample code to explain their operation. The symbol * is used to indicate any input including null.

Since:: 1.0
Version:: $Id: StringUtils.java 911986 2010-02-19 21:19:05Z niallp $
Author:: Apache Software Foundation, Apache Jakarta Turbine, Jon S. Stevens, Daniel L. Rall, Greg Coladonato, Ed Korthof, Rand McNeely, Fredrik Westermarck, Holger Krauth, Alexander Day Chaffee, Henning P. Schmiedehausen, Arun Mammen Thomas, Gary Gregory, Phil Steitz, Al Chou, Michael Davey, Reuben Sivan, Chris Hyzer, Scott Johnson
See Also:: String

Field Summary
`static String`	`EMPTY` The empty String `""`.

Method Summary

static String abbreviate(String str, int maxWidth)
Abbreviates a String using ellipses.

static String abbreviate(String str, int offset, int maxWidth)
Abbreviates a String using ellipses.

static boolean containsAny(String str, char... searchChars)
Checks if the String contains any character in the given set of characters.

static int countMatches(String str, String sub)
Counts how many times the substring appears in the larger String.

static String defaultIfEmpty(String str, String defaultStr)
Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

static String defaultString(String str)
Returns either the passed in String, or if the String is null, an empty String ("").

static String defaultString(String str, String defaultStr)
Returns either the passed in String, or if the String is null, the value of defaultStr.

static boolean isBlank(String str)
Checks if a String is whitespace, empty ("") or null.

static boolean isEmpty(String str)
Checks if a String is empty ("") or null.

static String join(Object[] array, char separator)
Joins the elements of the provided array into a single String containing the provided list of elements.

static String join(Object[] array, char separator, int startIndex, int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements.

static String join(Object[] array, String separator)
Joins the elements of the provided array into a single String containing the provided list of elements.

static String join(Object[] array, String separator, int startIndex, int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements.

static



<T> String

join(T... elements)
Joins the elements of the provided array into a single String containing the provided list of elements.

static String leftPad(String str, int size)
Left pad a String with spaces (' ').

static String leftPad(String str, int size, char padChar)
Left pad a String with a specified character.

static String leftPad(String str, int size, String padStr)
Left pad a String with a specified String.

static String replaceEach(String text, String[] searchList, String[] replacementList)
Replaces all occurrences of Strings within another String.

static String rightPad(String str, int size)
Right pad a String with spaces (' ').

static String rightPad(String str, int size, char padChar)
Right pad a String with a specified character.

static String rightPad(String str, int size, String padStr)
Right pad a String with a specified String.

static String[] split(String regex, CharSequence input)
A custom adaptation of Pattern.split(CharSequence, int).

static String toCamelCase(String string)
Convert a string to camel case

static String toCamelCaseLC(String string)
Convert a string to camel case starting with a lower case letter

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

EMPTY

public static final String EMPTY

The empty String "".

Since:: 2.0
See Also:: Constant Field Values

Method Detail

defaultString

public static String defaultString(String str)

Returns either the passed in String, or if the String is null, an empty String ("").

 StringUtils.defaultString(null)  = ""
 StringUtils.defaultString("")    = ""
 StringUtils.defaultString("bat") = "bat"

Parameters:: str - the String to check, may be null
Returns:: the passed in String, or the empty String if it was null
See Also:: String.valueOf(Object)

defaultString

public static String defaultString(String str,
                                   String defaultStr)

Returns either the passed in String, or if the String is null, the value of defaultStr.

 StringUtils.defaultString(null, "NULL")  = "NULL"
 StringUtils.defaultString("", "NULL")    = ""
 StringUtils.defaultString("bat", "NULL") = "bat"

Parameters:: str - the String to check, may be null; defaultStr - the default String to return if the input is null, may be null
Returns:: the passed in String, or the default if it was null
See Also:: String.valueOf(Object)

defaultIfEmpty

public static String defaultIfEmpty(String str,
                                    String defaultStr)

Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

 StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
 StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
 StringUtils.defaultIfEmpty("bat", "NULL") = "bat"

Parameters:: str - the String to check, may be null; defaultStr - the default String to return if the input is empty ("") or null, may be null
Returns:: the passed in String, or the default
See Also:: defaultString(String, String)

isEmpty

public static boolean isEmpty(String str)

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

 StringUtils.isEmpty(null)      = true
 StringUtils.isEmpty("")        = true
 StringUtils.isEmpty(" ")       = false
 StringUtils.isEmpty("bob")     = false
 StringUtils.isEmpty("  bob  ") = false

NOTE: This method changed in Lang version 2.0. It no longer trims the String. That functionality is available in isBlank().

Parameters:: str - the String to check, may be null
Returns:: true if the String is empty or null

isBlank

public static boolean isBlank(String str)

Checks if a String is whitespace, empty ("") or null.

 StringUtils.isBlank(null)      = true
 StringUtils.isBlank("")        = true
 StringUtils.isBlank(" ")       = true
 StringUtils.isBlank("bob")     = false
 StringUtils.isBlank("  bob  ") = false

Parameters:: str - the String to check, may be null
Returns:: true if the String is null, empty or whitespace
Since:: 2.0

countMatches

public static int countMatches(String str,
                               String sub)

Counts how many times the substring appears in the larger String.

A null or empty ("") String input returns 0.

 StringUtils.countMatches(null, *)       = 0
 StringUtils.countMatches("", *)         = 0
 StringUtils.countMatches("abba", null)  = 0
 StringUtils.countMatches("abba", "")    = 0
 StringUtils.countMatches("abba", "a")   = 2
 StringUtils.countMatches("abba", "ab")  = 1
 StringUtils.countMatches("abba", "xxx") = 0

Parameters:: str - the String to check, may be null; sub - the substring to count, may be null
Returns:: the number of occurrences, 0 if either String is null

rightPad

public static String rightPad(String str,
                              int size)

Right pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.rightPad(null, *)   = null
 StringUtils.rightPad("", 3)     = "   "
 StringUtils.rightPad("bat", 3)  = "bat"
 StringUtils.rightPad("bat", 5)  = "bat  "
 StringUtils.rightPad("bat", 1)  = "bat"
 StringUtils.rightPad("bat", -1) = "bat"

Parameters:: str - the String to pad out, may be null; size - the size to pad to
Returns:: right padded String or original String if no padding is necessary, null if null String input

rightPad

public static String rightPad(String str,
                              int size,
                              char padChar)

Right pad a String with a specified character.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)     = null
 StringUtils.rightPad("", 3, 'z')     = "zzz"
 StringUtils.rightPad("bat", 3, 'z')  = "bat"
 StringUtils.rightPad("bat", 5, 'z')  = "batzz"
 StringUtils.rightPad("bat", 1, 'z')  = "bat"
 StringUtils.rightPad("bat", -1, 'z') = "bat"

Parameters:: str - the String to pad out, may be null; size - the size to pad to; padChar - the character to pad with
Returns:: right padded String or original String if no padding is necessary, null if null String input
Since:: 2.0

rightPad

public static String rightPad(String str,
                              int size,
                              String padStr)

Right pad a String with a specified String.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)      = null
 StringUtils.rightPad("", 3, "z")      = "zzz"
 StringUtils.rightPad("bat", 3, "yz")  = "bat"
 StringUtils.rightPad("bat", 5, "yz")  = "batyz"
 StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
 StringUtils.rightPad("bat", 1, "yz")  = "bat"
 StringUtils.rightPad("bat", -1, "yz") = "bat"
 StringUtils.rightPad("bat", 5, null)  = "bat  "
 StringUtils.rightPad("bat", 5, "")    = "bat  "

Parameters:: str - the String to pad out, may be null; size - the size to pad to; padStr - the String to pad with, null or empty treated as single space
Returns:: right padded String or original String if no padding is necessary, null if null String input

leftPad

public static String leftPad(String str,
                             int size)

Left pad a String with spaces (' ').

The String is padded to the size of size.



  StringUtils.leftPad(null, *)   = null
 StringUtils.leftPad("", 3)     = "   "
 StringUtils.leftPad("bat", 3)  = "bat"
 StringUtils.leftPad("bat", 5)  = "  bat"
 StringUtils.leftPad("bat", 1)  = "bat"
 StringUtils.leftPad("bat", -1) = "bat"

Parameters:: str - the String to pad out, may be null; size - the size to pad to
Returns:: left padded String or original String if no padding is necessary, null if null String input





leftPad
public static String leftPad(String str,
                             int size,
                             char padChar)

Left pad a String with a specified character.

 Pad to a size of size.

  StringUtils.leftPad(null, *, *)     = null
 StringUtils.leftPad("", 3, 'z')     = "zzz"
 StringUtils.leftPad("bat", 3, 'z')  = "bat"
 StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
 StringUtils.leftPad("bat", 1, 'z')  = "bat"
 StringUtils.leftPad("bat", -1, 'z') = "bat"
 


Parameters:
str - the String to pad out, may be null
size - the size to pad to
padChar - the character to pad with
Returns:
left padded String or original String if no padding is necessary,
  null if null String input
Since:
  2.0






leftPad
public static String leftPad(String str,
                             int size,
                             String padStr)

Left pad a String with a specified String.

 Pad to a size of size.

  StringUtils.leftPad(null, *, *)      = null
 StringUtils.leftPad("", 3, "z")      = "zzz"
 StringUtils.leftPad("bat", 3, "yz")  = "bat"
 StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
 StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
 StringUtils.leftPad("bat", 1, "yz")  = "bat"
 StringUtils.leftPad("bat", -1, "yz") = "bat"
 StringUtils.leftPad("bat", 5, null)  = "  bat"
 StringUtils.leftPad("bat", 5, "")    = "  bat"
 


Parameters:
str - the String to pad out, may be null
size - the size to pad to
padStr - the String to pad with, null or empty treated as single space
Returns:
left padded String or original String if no padding is necessary,
  null if null String input





abbreviate
public static String abbreviate(String str,
                                int maxWidth)

Abbreviates a String using ellipses. This will turn
 "Now is the time for all good men" into "Now is the time for..."

 Specifically:
 

   If str is less than maxWidth characters
       long, return it.
   Else abbreviate it to (substring(str, 0, max-3) + "...").
   If maxWidth is less than 4, throw an
       IllegalArgumentException.
   In no case will it return a String of length greater than
       maxWidth.
 
 

  StringUtils.abbreviate(null, *)      = null
 StringUtils.abbreviate("", 4)        = ""
 StringUtils.abbreviate("abcdefg", 6) = "abc..."
 StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 4) = "a..."
 StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
 


Parameters:
str - the String to check, may be null
maxWidth - maximum length of result String, must be at least 4
Returns:
abbreviated String, null if null String input
Throws:
IllegalArgumentException - if the width is too small
Since:
  2.0






abbreviate
public static String abbreviate(String str,
                                int offset,
                                int maxWidth)

Abbreviates a String using ellipses. This will turn
 "Now is the time for all good men" into "...is the time for..."

 Works like abbreviate(String, int), but allows you to specify
 a "left edge" offset.  Note that this left edge is not necessarily going to
 be the leftmost character in the result, or the first character following the
 ellipses, but it will appear somewhere in the result.

 
In no case will it return a String of length greater than
 maxWidth.

  StringUtils.abbreviate(null, *, *)                = null
 StringUtils.abbreviate("", 0, 4)                  = ""
 StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
 StringUtils.abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
 StringUtils.abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
 StringUtils.abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
 StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
 StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
 StringUtils.abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
 StringUtils.abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException
 


Parameters:
str - the String to check, may be null
offset - left edge of source String
maxWidth - maximum length of result String, must be at least 4
Returns:
abbreviated String, null if null String input
Throws:
IllegalArgumentException - if the width is too small
Since:
  2.0






containsAny
public static boolean containsAny(String str,
                                  char... searchChars)

Checks if the String contains any character in the given
 set of characters.

 A null String will return false.
 A null or zero length search array will return false.

  StringUtils.containsAny(null, *)                = false
 StringUtils.containsAny("", *)                  = false
 StringUtils.containsAny(*, null)                = false
 StringUtils.containsAny(*, [])                  = false
 StringUtils.containsAny("zzabyycdxx",['z','a']) = true
 StringUtils.containsAny("zzabyycdxx",['b','y']) = true
 StringUtils.containsAny("aba", ['z'])           = false
 


Parameters:
str - the String to check, may be null
searchChars - the chars to search for, may be null
Returns:
the true if any of the chars are found,
 false if no match or null input
Since:
  2.4






replaceEach
public static String replaceEach(String text,
                                 String[] searchList,
                                 String[] replacementList)


 Replaces all occurrences of Strings within another String.
 

 
 A null reference passed to this method is a no-op, or if
 any "search string" or "string to replace" is null, that replace will be
 ignored. This will not repeat. For repeating replaces, call the
 overloaded method.
 

   StringUtils.replaceEach(null, *, *)        = null
  StringUtils.replaceEach("", *, *)          = ""
  StringUtils.replaceEach("aba", null, null) = "aba"
  StringUtils.replaceEach("aba", new String[0], null) = "aba"
  StringUtils.replaceEach("aba", null, new String[0]) = "aba"
  StringUtils.replaceEach("aba", new String[]{"a"}, null)  = "aba"
  StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""})  = "b"
  StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"})  = "aba"
  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"})  = "wcte"
  (example of how it does not repeat)
  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"})  = "dcte"
 


Parameters:
text - text to search and replace in, no-op if null
searchList - the Strings to search for, no-op if null
replacementList - the Strings to replace them with, no-op if null
Returns:
the text with any replacements processed, null if
         null String input
Throws:
IndexOutOfBoundsException - if the lengths of the arrays are not the same (null is ok,
             and/or size 0)
Since:
  2.4






join
public static <T> String join(T... elements)

Joins the elements of the provided array into a single String
 containing the provided list of elements.

 No separator is added to the joined String.
 Null objects or empty strings within the array are represented by
 empty strings.

  StringUtils.join(null)            = null
 StringUtils.join([])              = ""
 StringUtils.join([null])          = ""
 StringUtils.join(["a", "b", "c"]) = "abc"
 StringUtils.join([null, "", "a"]) = "a"
 


Type Parameters:
T - the specific type of values to join together
Parameters:
elements - the values to join together, may be null
Returns:
the joined String, null if null array input
Since:
  2.0, 3.0 Changed signature to use varargs






join
public static String join(Object[] array,
                          char 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.
 Null objects or empty strings within the array are represented by
 empty strings.

  StringUtils.join(null, *)               = null
 StringUtils.join([], *)                 = ""
 StringUtils.join([null], *)             = ""
 StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
 StringUtils.join(["a", "b", "c"], null) = "abc"
 StringUtils.join([null, "", "a"], ';')  = ";;a"
 


Parameters:
array - the array of values to join together, may be null
separator - the separator character to use
Returns:
the joined String, null if null array input
Since:
  2.0






join
public static String join(Object[] array,
                          char separator,
                          int startIndex,
                          int endIndex)

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.
 Null objects or empty strings within the array are represented by
 empty strings.

  StringUtils.join(null, *)               = null
 StringUtils.join([], *)                 = ""
 StringUtils.join([null], *)             = ""
 StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
 StringUtils.join(["a", "b", "c"], null) = "abc"
 StringUtils.join([null, "", "a"], ';')  = ";;a"
 


Parameters:
array - the array of values to join together, may be null
separator - the separator character to use
startIndex - the first index to start joining from.  It is
 an error to pass in an end index past the end of the array
endIndex - the index to stop joining from (exclusive). It is
 an error to pass in an end index past the end of the array
Returns:
the joined String, null if null array input
Since:
  2.0






join
public static String join(Object[] array,
                          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 an empty String ("").
 Null objects or empty strings within the array are represented by
 empty strings.

  StringUtils.join(null, *)                = null
 StringUtils.join([], *)                  = ""
 StringUtils.join([null], *)              = ""
 StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
 StringUtils.join(["a", "b", "c"], null)  = "abc"
 StringUtils.join(["a", "b", "c"], "")    = "abc"
 StringUtils.join([null, "", "a"], ',')   = ",,a"
 


Parameters:
array - the array of values to join together, may be null
separator - the separator character to use, null treated as ""
Returns:
the joined String, null if null array input





join
public static String join(Object[] array,
                          String separator,
                          int startIndex,
                          int endIndex)

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 an empty String ("").
 Null objects or empty strings within the array are represented by
 empty strings.

  StringUtils.join(null, *)                = null
 StringUtils.join([], *)                  = ""
 StringUtils.join([null], *)              = ""
 StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
 StringUtils.join(["a", "b", "c"], null)  = "abc"
 StringUtils.join(["a", "b", "c"], "")    = "abc"
 StringUtils.join([null, "", "a"], ',')   = ",,a"
 


Parameters:
array - the array of values to join together, may be null
separator - the separator character to use, null treated as ""
startIndex - the first index to start joining from.  It is
 an error to pass in an end index past the end of the array
endIndex - the index to stop joining from (exclusive). It is
 an error to pass in an end index past the end of the array
Returns:
the joined String, null if null array input





toCamelCase
public static String toCamelCase(String string)

Convert a string to camel case








toCamelCaseLC
public static String toCamelCaseLC(String string)

Convert a string to camel case starting with a lower case letter








split
public static String[] split(String regex,
                             CharSequence input)

A custom adaptation of Pattern.split(CharSequence, int).
 
 This is useful if the matched split-tokens should be returned as well.
 For example: 
 split("e", "hello world")    // ["h", "e", "llo world"]
 split("o", "hello world")    // ["hell", "o", " w", "o", "rld"]
 split("[eo]", "hello world") // ["h", "e", "ll", "o", " w", "o", "rld"]
 
 
 The result will always be an odd-length array.

















  
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org.jooq.tools Class StringUtils

EMPTY

defaultString

defaultString

defaultIfEmpty

isEmpty

isBlank

countMatches

rightPad

rightPad

rightPad

leftPad

leftPad

leftPad

abbreviate

abbreviate

containsAny

replaceEach

join

join

join

join

join

toCamelCase

toCamelCaseLC

split

org.jooq.tools
Class StringUtils