org.apache.maven.shared.utils
Class StringUtils

java.lang.Object
  extended by org.apache.maven.shared.utils.StringUtils

public class StringUtils
extends Object

Common String manipulation routines.

Originally from Turbine, the GenerationJavaCore library and Velocity. Later a lots methods from commons-lang StringUtils got added too. Gradually smaller additions and fixes have been made over the time by various ASF committers.

Version:
$Id: StringUtils.java 1402496 2012-10-26 13:00:39Z rfscholte $
Author:
Jon S. Stevens, Daniel Rall, Greg Coladonato, Henri Yandell, Ed Korthof, Rand McNeely, Stephen Colebourne, Fredrik Westermarck, Holger Krauth, Alexander Day Chaffee

Constructor Summary
StringUtils()
          StringUtils instances should NOT be constructed in standard programming.
 
Method Summary
static String abbreviate(String s, int maxWidth)
          Turn "Now is the time for all good men" into "Now is the time for..."

Specifically:

If str is less than max characters long, return it.

static String abbreviate(String s, int offset, int maxWidth)
          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.

static String addAndDeHump(String view)
          Take the input string and un-camel-case it.
static String capitalise(String str)
          Capitalise a String.
static String capitaliseAllWords(String str)
          Capitalise all the words in a String.
static String capitalizeFirstLetter(String data)
          Convert the first character of the given String to uppercase.
static String center(String str, int size)
          Center a String in a larger String of size n.
static String center(String str, int size, String delim)
          Center a String in a larger String of size n.
static String chomp(String str)
          Remove the last newline, and everything after it from a String.
static String chomp(String str, String sep)
          Remove the last value of a supplied String, and everything after it from a String.
static String chompLast(String str)
          Remove a newline if and only if it is at the end of the supplied String.
static String chompLast(String str, String sep)
          Remove a value if and only if the String ends with that value.
static String chop(String str)
          Remove the last character from a String.
static String chopNewline(String str)
          Remove \n from end of a String if it's there.
static String clean(String str)
          Removes control characters, including whitespace, from both ends of this String, handling null by returning an empty String.
static String concatenate(Object... array)
          Concatenates elements of an array into a single String.
static boolean contains(String str, char searchChar)
          Checks if String contains a search character, handling null.
static boolean contains(String str, String searchStr)
          Checks if String contains a search String, handling null.
static int countMatches(String str, String sub)
          How many times is the substring in the larger String.
static String defaultString(Object obj)
          Returns either the passed in Object as a String, or, if the Object is null, an empty String.
static String defaultString(Object obj, String defaultString)
          Returns either the passed in Object as a String, or, if the Object is null, a passed in default String.
static String deleteWhitespace(String str)
          Deletes all whitespaces from a String.
static String difference(String s1, String s2)
          Compare two strings, and return the portion where they differ.
static int differenceAt(String s1, String s2)
          Compare two strings, and return the index at which the strings begin to differ.
static boolean equals(String str1, String str2)
          Compares two Strings, returning true if they are equal.
static boolean equalsIgnoreCase(String str1, String str2)
          Compares two Strings, returning true if they are equal ignoring the case.
static String escape(String str)
          Escapes any values it finds into their String form.
static String escape(String source, char[] escapedChars, char escapeChar)
           
static String getChomp(String str, String sep)
          Remove everything and return the last value of a supplied String, and everything after it from a String.
static String getNestedString(String str, String tag)
          Get the String that is nested in between two instances of the same String.
static String getNestedString(String str, String open, String close)
          Get the String that is nested in between two Strings.
static String getPrechomp(String str, String sep)
          Remove and return everything before the first value of a supplied String from another String.
static int indexOfAny(String str, String... searchStrs)
          Find the first index of any of a set of potential substrings.
static String interpolate(String text, Map<?,?> namespace)
          Fill all 'variables' in the given text with the values from the map.
static boolean isAlpha(String str)
          Checks if the String contains only unicode letters.
static boolean isAlphanumeric(String str)
          Checks if the String contains only unicode letters or digits.
static boolean isAlphanumericSpace(String str)
          Checks if the String contains only unicode letters, digits or space (' ').
static boolean isAlphaSpace(String str)
          Checks if the String contains only unicode letters and space (' ').
static boolean isBlank(String str)
           Checks if a String is whitespace, empty ("") or null.
static boolean isEmpty(String str)
          Checks if a (trimmed) String is null or empty.
static boolean isNotBlank(String str)
           Checks if a String is not empty (""), not null and not whitespace only.
static boolean isNotEmpty(String str)
          Checks if a String is non null and is not empty (length > 0).
static boolean isNumeric(String str)
          Checks if the String contains only unicode digits.
static boolean isWhitespace(String str)
          Checks if the String contains only whitespace.
static String join(Iterator<?> iterator, String separator)
          Joins the elements of the provided Iterator into a single String containing the provided 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 int lastIndexOfAny(String str, String... searchStrs)
          Find the latest index of any of a set of potential substrings.
static String left(String str, int len)
          Gets the leftmost n characters of a String.
static String leftPad(String str, int size)
          Left pad a String with spaces.
static String leftPad(String str, int size, String delim)
          Left pad a String with a specified string.
static String lowerCase(String str)
          Convert a String to lower case, null String returns null.
static String lowercaseFirstLetter(String data)
          Convert the first character of the given String to lowercase.
static String mid(String str, int pos, int len)
          Gets n characters from the middle of a String.
static String overlayString(String text, String overlay, int start, int end)
          Overlay a part of a String with another String.
static String prechomp(String str, String sep)
          Remove the first value of a supplied String, and everything before it from a String.
static String quoteAndEscape(String source, char quoteChar)
          Quote and escape a String with the given character, handling null.
static String quoteAndEscape(String source, char quoteChar, char[] quotingTriggers)
          Quote and escape a String with the given character, handling null.
static String quoteAndEscape(String source, char quoteChar, char[] escapedChars, char[] quotingTriggers, char escapeChar, boolean force)
           
static String quoteAndEscape(String source, char quoteChar, char[] escapedChars, char escapeChar, boolean force)
           
static String removeAndHump(String data, String replaceThis)
          This is basically the inverse of addAndDeHump(String).
static String removeDuplicateWhitespace(String s)
          Remove all duplicate whitespace characters and line terminators are replaced with a single space.
static String repeat(String str, int repeat)
          Repeat a String n times to form a new string.
static String replace(String text, char repl, char with)
          Replace all occurances of a char within another char.
static String replace(String text, char repl, char with, int max)
          Replace a char with another char inside a larger String, for the first max values of the search char.
static String replace(String text, String repl, String with)
          Replace all occurances of a String within another String.
static String replace(String text, String repl, String with, int max)
          Replace a String with another String inside a larger String, for the first max values of the search String.
static String replaceOnce(String text, char repl, char with)
          Replace a char with another char inside a larger String, once.
static String replaceOnce(String text, String repl, String with)
          Replace a String with another String inside a larger String, once.
static String reverse(String str)
          Reverse a String.
static String reverseDelimitedString(String str, String delimiter)
          Reverses a String that is delimited by a specific character.
static String right(String str, int len)
          Gets the rightmost n characters of a String.
static String rightPad(String str, int size)
          Right pad a String with spaces.
static String rightPad(String str, int size, String delim)
          Right pad a String with a specified string.
static String[] split(String str)
          Splits the provided text into a array, using whitespace as the separator.
static String[] split(String text, String separator)
           
static String[] split(String str, String separator, int max)
          Splits the provided text into a array, based on a given separator.
static String strip(String str)
          Remove whitespace from the front and back of a String.
static String strip(String str, String delim)
          Remove a specified String from the front and back of a String.
static String[] stripAll(String... strs)
          Strip whitespace from the front and back of every String in the array.
static String[] stripAll(String[] strs, String delimiter)
          Strip the specified delimiter from the front and back of every String in the array.
static String stripEnd(String str, String strip)
          Strip any of a supplied String from the end of a String.
static String stripStart(String str, String strip)
          Strip any of a supplied String from the start of a String.
static String substring(String str, int start)
          Gets a substring from the specified string avoiding exceptions.
static String substring(String str, int start, int end)
          Gets a substring from the specified String avoiding exceptions.
static String swapCase(String str)
          Swaps the case of String.
static String trim(String str)
          Removes control characters, including whitespace, from both ends of this String, handling null by returning null.
static String uncapitalise(String str)
          Uncapitalise a String.
static String uncapitaliseAllWords(String str)
          Uncapitalise all the words in a string.
static String unifyLineSeparators(String s)
          Parses the given String and replaces all occurrences of '\n', '\r' and '\r\n' with the system line separator.
static String unifyLineSeparators(String s, String ls)
          Parses the given String and replaces all occurrences of '\n', '\r' and '\r\n' with the system line separator.
static String upperCase(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, 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 manager to operate.

Method Detail

clean

@Nonnull
public static String clean(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 String trim(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()

deleteWhitespace

@Nonnull
public static String deleteWhitespace(@Nonnull
                                              String str)

Deletes all whitespaces from a String.

Whitespace is defined by Character.isWhitespace(char).

Parameters:
str - String target to delete whitespace from
Returns:
the String without whitespaces
Throws:
NullPointerException

isNotEmpty

public static boolean isNotEmpty(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(@Nullable
                              String str)

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

Note: In future releases, this method will no longer trim the input string such that it works complementary to isNotEmpty(String). Code that wants to test for whitespace-only strings should be migrated to use isBlank(String) instead.

Parameters:
str - the String to check
Returns:
true if the String is null, or length zero once trimmed

isBlank

public static boolean isBlank(@Nullable
                              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

isNotBlank

public static boolean isNotBlank(@Nullable
                                 String str)

Checks if a String is not empty (""), not null and not whitespace only.

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

Parameters:
str - the String to check, may be null
Returns:
true if the String is not empty and not null and not whitespace

equals

public static boolean equals(@Nullable
                             String str1,
                             @Nullable
                             String str2)

Compares two Strings, returning true if they are equal.

nulls are handled without exceptions. Two null references are considered to be equal. The 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(String str1,
                                       String str2)

Compares two Strings, returning true if they are equal ignoring the 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(String str,
                             String... searchStrs)

Find the first 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 first index of any of the searchStrs in str
Throws:
NullPointerException - if any of searchStrs[i] is null

lastIndexOfAny

public static int lastIndexOfAny(String str,
                                 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 String substring(String str,
                               int start)

Gets a substring from 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 String substring(String str,
                               int start,
                               int end)

Gets a substring from 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 String left(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:
IllegalArgumentException - if len is less than zero

right

public static String right(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:
IllegalArgumentException - if len is less than zero

mid

public static String mid(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
IllegalArgumentException - if len is less than zero

split

@Nonnull
public static String[] split(@Nonnull
                                     String str)

Splits the provided text into a array, 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

@Nonnull
public static String[] split(@Nonnull
                                     String text,
                                     String separator)
See Also:
split(String, String, int)

split

@Nonnull
public static String[] split(@Nonnull
                                     String str,
                                     String separator,
                                     int max)

Splits the provided text into a array, 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 array. A zero or negative value implies no limit.
Returns:
an array of parsed Strings

concatenate

@Nonnull
public static String concatenate(@Nonnull
                                         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

@Nonnull
public static String join(@Nonnull
                                  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 a blank String.

Parameters:
array - the array of values to join together
separator - the separator character to use
Returns:
the joined String

join

@Nonnull
public static String join(@Nonnull
                                  Iterator<?> iterator,
                                  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 String replaceOnce(@Nullable
                                 String text,
                                 char repl,
                                 char with)

Replace a char with another char inside a larger String, once.

A null reference passed to this method is a no-op.

Parameters:
text - text to search and replace in
repl - char to search for
with - char to replace with
Returns:
the text with any replacements processed
See Also:
replace(String text, char repl, char with, int max)

replace

public static String replace(@Nullable
                             String text,
                             char repl,
                             char with)

Replace all occurances of a char within another char.

A null reference passed to this method is a no-op.

Parameters:
text - text to search and replace in
repl - char to search for
with - char to replace with
Returns:
the text with any replacements processed
See Also:
replace(String text, char repl, char with, int max)

replace

public static String replace(@Nullable
                             String text,
                             char repl,
                             char with,
                             int max)

Replace a char with another char inside a larger String, for the first max values of the search char.

A null reference passed to this method is a no-op.

Parameters:
text - text to search and replace in
repl - char to search for
with - char to replace with
max - maximum number of values to replace, or -1 if no maximum
Returns:
the text with any replacements processed

replaceOnce

public static String replaceOnce(@Nullable
                                 String text,
                                 @Nullable
                                 String repl,
                                 @Nullable
                                 String with)

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

A null reference 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
Returns:
the text with any replacements processed
See Also:
replace(String text, String repl, String with, int max)

replace

public static String replace(@Nullable
                             String text,
                             @Nullable
                             String repl,
                             @Nullable
                             String with)

Replace all occurances of a String within another String.

A null reference 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
Returns:
the text with any replacements processed
See Also:
replace(String text, String repl, String with, int max)

replace

public static String replace(@Nullable
                             String text,
                             @Nullable
                             String repl,
                             @Nullable
                             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 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

overlayString

@Nonnull
public static String overlayString(@Nonnull
                                           String text,
                                           @Nonnull
                                           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

@Nonnull
public static String center(@Nonnull
                                    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

@Nonnull
public static String center(@Nonnull
                                    String str,
                                    int size,
                                    @Nonnull
                                    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

@Nonnull
public static String chomp(@Nonnull
                                   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

@Nonnull
public static String chomp(@Nonnull
                                   String str,
                                   @Nonnull
                                   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

@Nonnull
public static String chompLast(@Nonnull
                                       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

@Nonnull
public static String chompLast(@Nonnull
                                       String str,
                                       @Nonnull
                                       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

@Nonnull
public static String getChomp(@Nonnull
                                      String str,
                                      @Nonnull
                                      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

@Nonnull
public static String prechomp(@Nonnull
                                      String str,
                                      @Nonnull
                                      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

@Nonnull
public static String getPrechomp(@Nonnull
                                         String str,
                                         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

@Nonnull
public static String chop(@Nonnull
                                  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

@Nonnull
public static String chopNewline(@Nonnull
                                         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

@Nonnull
public static String escape(@Nonnull
                                    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

@Nonnull
public static String repeat(@Nonnull
                                    String str,
                                    int repeat)

Repeat a String n times to form a new string.

Parameters:
str - String to repeat
repeat - number of times to repeat str
Returns:
String with repeated String
Throws:
NegativeArraySizeException - if repeat < 0
NullPointerException - if str is null

rightPad

@Nonnull
public static String rightPad(@Nonnull
                                      String str,
                                      int size)

Right pad a String with spaces.

The String is padded to the size of n.

Parameters:
str - String to repeat
size - number of times to repeat str
Returns:
right padded String
Throws:
NullPointerException - if str is null

rightPad

@Nonnull
public static String rightPad(@Nonnull
                                      String str,
                                      int size,
                                      @Nonnull
                                      String delim)

Right pad a String with a specified string.

The String is padded to the size of n.

Parameters:
str - String to pad out
size - 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

@Nonnull
public static String leftPad(@Nonnull
                                     String str,
                                     int size)

Left pad a String with spaces.

The String is padded to the size of n.

Parameters:
str - String to pad out
size - size to pad to
Returns:
left padded String
Throws:
NullPointerException - if str or delim is null

leftPad

@Nonnull
public static String leftPad(@Nonnull
                                     String str,
                                     int size,
                                     @Nonnull
                                     String delim)
Left pad a String with a specified string. Pad to a size of n.

Parameters:
str - String to pad out
size - 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 String strip(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 String strip(String str,
                           @Nullable
                           String delim)

Remove a specified String from the front and back of a String.

If whitespace is wanted to be removed, used the strip(java.lang.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 String[] stripAll(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 String[] stripAll(String[] strs,
                                @Nullable
                                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 String stripEnd(String str,
                              @Nullable
                              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 String stripStart(String str,
                                @Nullable
                                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 String upperCase(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 String lowerCase(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 String uncapitalise(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 String capitalise(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 String swapCase(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 String capitaliseAllWords(String str)

Capitalise all the words in a String.

Uses Character.isWhitespace(char) as a separator between words.

null will return null.

Parameters:
str - the String to capitalise
Returns:
capitalised String

uncapitaliseAllWords

public static String uncapitaliseAllWords(String str)

Uncapitalise all the words in a string.

Uses Character.isWhitespace(char) as a separator between words.

null will return null.

Parameters:
str - the string to uncapitalise
Returns:
uncapitalised string

getNestedString

public static String getNestedString(String str,
                                     @Nonnull
                                     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 String getNestedString(String str,
                                     @Nonnull
                                     String open,
                                     @Nonnull
                                     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(@Nullable
                               String str,
                               @Nonnull
                               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(String str)

Checks if the String contains only unicode letters.

null will return false. An empty String will return true.

Parameters:
str - the String to check
Returns:
true if only contains letters, and is non-null

isWhitespace

public static boolean isWhitespace(String str)

Checks if the String contains only whitespace.

null will return false. An empty String will return true.

Parameters:
str - the String to check
Returns:
true if only contains whitespace, and is non-null

isAlphaSpace

public static boolean isAlphaSpace(String str)

Checks if the String contains only unicode letters and space (' ').

null will return false. An 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(String str)

Checks if the String contains only unicode letters or digits.

null will return false. An 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(String str)

Checks if the String contains only unicode letters, digits or space (' ').

null will return false. An 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(String str)

Checks if the String contains only unicode digits.

null will return false. An empty String will return true.

Parameters:
str - the String to check
Returns:
true if only contains digits, and is non-null

defaultString

@Nonnull
public static String defaultString(Object obj)

Returns either the passed in Object as a String, or, if the Object is null, an empty String.

Parameters:
obj - the Object to check
Returns:
the passed in Object's toString, or blank if it was null

defaultString

@Nonnull
public static String defaultString(Object obj,
                                           @Nonnull
                                           String defaultString)

Returns either the passed in Object as a String, or, if the Object is null, a passed in default String.

Parameters:
obj - the Object to check
defaultString - the default String to return if str is null
Returns:
the passed in string, or the default if it was null

reverse

public static String reverse(String str)

Reverse a String.

null String returns null.

Parameters:
str - the String to reverse
Returns:
the reversed String

reverseDelimitedString

@Nonnull
public static String reverseDelimitedString(@Nonnull
                                                    String str,
                                                    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

abbreviate

@Nonnull
public static String abbreviate(@Nonnull
                                        String s,
                                        int maxWidth)
Turn "Now is the time for all good men" into "Now is the time for..."

Specifically:

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

Parameters:
maxWidth - maximum length of result string

abbreviate

@Nonnull
public static String abbreviate(@Nonnull
                                        String s,
                                        int offset,
                                        int maxWidth)
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.

Parameters:
offset - left edge of source string
maxWidth - maximum length of result string

difference

public static String difference(@Nonnull
                                String s1,
                                @Nonnull
                                String s2)
Compare two strings, and return the portion where they differ. (More precisely, return the remainder of the second string, starting from where it's different from the first.)

E.g. strdiff("i am a machine", "i am a robot") -> "robot"

Returns:
the portion of s2 where it differs from s1; returns the empty string ("") if they are equal

differenceAt

public static int differenceAt(@Nonnull
                               String s1,
                               @Nonnull
                               String s2)
Compare two strings, and return the index at which the strings begin to differ.

E.g. strdiff("i am a machine", "i am a robot") -> 7

Returns:
the index where s2 and s1 begin to differ; -1 if they are equal

interpolate

public static String interpolate(String text,
                                 @Nonnull
                                 Map<?,?> namespace)
Fill all 'variables' in the given text with the values from the map. Any text looking like '${key}' will get replaced by the value stored in the namespace map under the 'key'.

Parameters:
text -
namespace -
Returns:
the interpolated text.

removeAndHump

@Nonnull
public static String removeAndHump(@Nonnull
                                           String data,
                                           @Nonnull
                                           String replaceThis)
This is basically the inverse of addAndDeHump(String). It will remove the 'replaceThis' parameter and uppercase the next character afterwards.
 removeAndHump( "this-is-it", %quot;-" );
 
will become 'ThisIsIt'.

Parameters:
data -
replaceThis -
Returns:
humped String

capitalizeFirstLetter

@Nonnull
public static String capitalizeFirstLetter(@Nonnull
                                                   String data)
Convert the first character of the given String to uppercase. This method will not trim of spaces!

Attention: this method will currently throw a IndexOutOfBoundsException for empty strings!

Parameters:
data - the String to get capitalized
Returns:
data string with the first character transformed to uppercase
Throws:
NullPointerException - if data is null

lowercaseFirstLetter

@Nonnull
public static String lowercaseFirstLetter(@Nonnull
                                                  String data)
Convert the first character of the given String to lowercase. This method will not trim of spaces!

Attention: this method will currently throw a IndexOutOfBoundsException for empty strings!

Parameters:
data - the String to get it's first character lower-cased.
Returns:
data string with the first character transformed to lowercase
Throws:
NullPointerException - if data is null

addAndDeHump

@Nonnull
public static String addAndDeHump(@Nonnull
                                          String view)
Take the input string and un-camel-case it.

'ThisIsIt' will become 'this-is-it'.

Parameters:
view -
Returns:
deHumped String

quoteAndEscape

public static String quoteAndEscape(@Nullable
                                    String source,
                                    char quoteChar)

Quote and escape a String with the given character, handling null.

 StringUtils.quoteAndEscape(null, *)    = null
 StringUtils.quoteAndEscape("", *)      = ""
 StringUtils.quoteAndEscape("abc", '"') = abc
 StringUtils.quoteAndEscape("a\"bc", '"') = "a\"bc"
 StringUtils.quoteAndEscape("a\"bc", '\'') = 'a\"bc'
 

Parameters:
source -
quoteChar -
Returns:
the String quoted and escaped
See Also:
quoteAndEscape(String, char, char[], char[], char, boolean), quoteAndEscape(String, char, char[], char[], char, boolean)

quoteAndEscape

public static String quoteAndEscape(@Nullable
                                    String source,
                                    char quoteChar,
                                    @Nonnull
                                    char[] quotingTriggers)

Quote and escape a String with the given character, handling null.

Parameters:
source -
quoteChar -
quotingTriggers -
Returns:
the String quoted and escaped
See Also:
quoteAndEscape(String, char, char[], char[], char, boolean)

quoteAndEscape

public static String quoteAndEscape(@Nullable
                                    String source,
                                    char quoteChar,
                                    @Nonnull
                                    char[] escapedChars,
                                    char escapeChar,
                                    boolean force)
Parameters:
source -
quoteChar -
escapedChars -
escapeChar -
force -
Returns:
the String quoted and escaped
See Also:
quoteAndEscape(String, char, char[], char[], char, boolean)

quoteAndEscape

public static String quoteAndEscape(@Nullable
                                    String source,
                                    char quoteChar,
                                    @Nonnull
                                    char[] escapedChars,
                                    @Nonnull
                                    char[] quotingTriggers,
                                    char escapeChar,
                                    boolean force)
Parameters:
source -
quoteChar -
escapedChars -
quotingTriggers -
escapeChar -
force -
Returns:
the String quoted and escaped

escape

public static String escape(@Nullable
                            String source,
                            @Nonnull
                            char[] escapedChars,
                            char escapeChar)
Parameters:
source -
escapedChars -
escapeChar -
Returns:
the String escaped

removeDuplicateWhitespace

@Nonnull
public static String removeDuplicateWhitespace(@Nonnull
                                                       String s)
Remove all duplicate whitespace characters and line terminators are replaced with a single space.

Parameters:
s - a not null String
Returns:
a string with unique whitespace.

unifyLineSeparators

public static String unifyLineSeparators(@Nullable
                                         String s)
Parses the given String and replaces all occurrences of '\n', '\r' and '\r\n' with the system line separator.

Parameters:
s - a not null String
Returns:
a String that contains only System line separators.
See Also:
unifyLineSeparators(String, String)

unifyLineSeparators

public static String unifyLineSeparators(@Nullable
                                         String s,
                                         @Nullable
                                         String ls)
Parses the given String and replaces all occurrences of '\n', '\r' and '\r\n' with the system line separator.

Parameters:
s - a not null String
ls - the wanted line separator ("\n" on UNIX), if null using the System line separator.
Returns:
a String that contains only System line separators.
Throws:
IllegalArgumentException - if ls is not '\n', '\r' and '\r\n' characters.

contains

public static boolean contains(@Nullable
                               String str,
                               char searchChar)

Checks if String contains a search character, handling null. This method uses String.indexOf(int).

A null or empty ("") String will return false.

 StringUtils.contains(null, *)    = false
 StringUtils.contains("", *)      = false
 StringUtils.contains("abc", 'a') = true
 StringUtils.contains("abc", 'z') = false
 

Parameters:
str - the String to check, may be null
searchChar - the character to find
Returns:
true if the String contains the search character, false if not or null string input

contains

public static boolean contains(@Nullable
                               String str,
                               @Nullable
                               String searchStr)

Checks if String contains a search String, handling null. This method uses String.indexOf(int).

A null String will return false.

 StringUtils.contains(null, *)     = false
 StringUtils.contains(*, null)     = false
 StringUtils.contains("", "")      = true
 StringUtils.contains("abc", "")   = true
 StringUtils.contains("abc", "a")  = true
 StringUtils.contains("abc", "z")  = false
 

Parameters:
str - the String to check, may be null
searchStr - the String to find, may be null
Returns:
true if the String contains the search String, false if not or null string input


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