Package software.amazon.smithy.utils

Class StringUtils

java.lang.Object

software.amazon.smithy.utils.StringUtils

public final class StringUtils
extends Object

Operations on String that are null safe.

• IsEmpty/IsBlank - checks if a String contains text
• Trim - removes leading and trailing whitespace
• Equals/Compare - compares two strings null-safe
• Substring - null-safe substring extraction
• UpperCase/LowerCase/Capitalize/Uncapitalize - changes the case of a String

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.

This class's source was modified from the Apache commons-lang and Apache commons-text libraries: https://github.com/apache/commons-lang/, https://github.com/apache/commons-text/

#ThreadSafe#

See Also:

• String
• Apache Commons Lang
• Apache Commons Text
• Elephant bird license

Method Summary

Modifier and Type	Method	Description
static String	capitalize(String str)	Capitalizes a String changing the first character to title case as per Character.toTitleCase(int).
static boolean	equals(String cs1, String cs2)	Compares two Strings, returning true if they represent equal sequences of characters.
static String	escapeJavaString(Object object, String indent)
static boolean	isBlank(CharSequence cs)	Checks if a CharSequence is empty (""), null or whitespace only.
static boolean	isEmpty(CharSequence cs)	Checks if a CharSequence is empty ("") or null.
static boolean	isNotBlank(CharSequence cs)	Checks if a CharSequence is not empty (""), not null and not whitespace only.
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 int	levenshteinDistance(CharSequence left, CharSequence right, int threshold)	Find the Levenshtein distance between two CharSequences if it's less than or equal to a given threshold.
static String	lowerCase(String str)	Converts a String to lower case as per String.toLowerCase().
static String	repeat(char ch, int repeat)	Returns padding using the specified delimiter repeated to a given length.
static String	repeat(String str, int repeat)	Repeat a String repeat times to form a new 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 boolean	startsWithIgnoreCase(String str, String prefix)	Tests if this string starts with the specified prefix ignoring case considerations.
static String	strip(String str, String stripChars)	Strips any of a set of characters from the start and end of a String.
static String	stripEnd(String str, String stripChars)	Strips any of a set of characters from the end of a String.
static String	stripStart(String str, String stripChars)	Strips any of a set of characters from the start of a String.
static String	stripToEmpty(String str)	Strips whitespace from the start and end of a String returning an empty String if null input.
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	trim(String str)	Removes control characters (char <= 32) from both ends of this String, handling null by returning null.
static String	trimToEmpty(String str)	Removes control characters (char <= 32) from both ends of this String returning an empty String ("") if the String is empty ("") after the trim or if it is null.
static String	trimToNull(String str)	Removes control characters (char <= 32) from both ends of this String returning null if the String is empty ("") after the trim or if it is null.
static String	uncapitalize(String str)	Uncapitalizes a String, changing the first character to lower case as per Character.toLowerCase(int).
static String	upperCase(String str)	Converts a String to upper case as per String.toUpperCase().
static String	wrap(String str, int wrapLength)	Wraps a single line of text, identifying words by ' '.
static String	wrap(String str, int wrapLength, String newLineStr, boolean wrapLongWords)	Wraps a single line of text, identifying words by ' '.
static String	wrap(String str, int wrapLength, String newLineStr, boolean wrapLongWords, String wrapOn)	Wraps a single line of text, identifying words by wrapOn.

Methods inherited from class java.lang.Object

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

Method Details

isEmpty

public static boolean isEmpty(CharSequence cs)

Checks if a CharSequence 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 CharSequence. That functionality is available in isBlank().

Parameters:

cs - the CharSequence to check, may be null

Returns:

true if the CharSequence is empty or null

Since:

3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)

See Also:

• Source

isBlank

public static boolean isBlank(CharSequence cs)

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

Whitespace is defined by Character.isWhitespace(char).

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

Parameters:

cs - the CharSequence to check, may be null

Returns:

true if the CharSequence is null, empty or whitespace only

Since:

2.0, 3.0 Changed signature from isBlank(String) to isBlank(CharSequence)

See Also:

• Source

isNotBlank

public static boolean isNotBlank(CharSequence cs)

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

Whitespace is defined by Character.isWhitespace(char).

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

Parameters:

cs - the CharSequence to check, may be null

Returns:

true if the CharSequence is not empty and not null and not whitespace only

Since:

2.0, 3.0 Changed signature from isNotBlank(String) to isNotBlank(CharSequence)

See Also:

• Source

trim

public static String trim(String str)

Removes control characters (char <= 32) from both ends of this String, handling null by returning null.

The String is trimmed using String.trim(). Trim removes start and end characters <= 32.

 StringUtils.trim(null)          = null
 StringUtils.trim("")            = ""
 StringUtils.trim("     ")       = ""
 StringUtils.trim("abc")         = "abc"
 StringUtils.trim("    abc    ") = "abc"
 

Parameters:

str - the String to be trimmed, may be null

Returns:

the trimmed string, null if null String input

See Also:

• Source

trimToNull

public static String trimToNull(String str)

Removes control characters (char <= 32) from both ends of this String returning null if the String is empty ("") after the trim or if it is null.

The String is trimmed using String.trim(). Trim removes start and end characters <= 32.

 StringUtils.trimToNull(null)          = null
 StringUtils.trimToNull("")            = null
 StringUtils.trimToNull("     ")       = null
 StringUtils.trimToNull("abc")         = "abc"
 StringUtils.trimToNull("    abc    ") = "abc"
 

Parameters:

str - the String to be trimmed, may be null

Returns:

the trimmed String, null if only chars <= 32, empty or null String input

Since:

2.0

See Also:

• Source

trimToEmpty

public static String trimToEmpty(String str)

Removes control characters (char <= 32) from both ends of this String returning an empty String ("") if the String is empty ("") after the trim or if it is null.

The String is trimmed using String.trim(). Trim removes start and end characters <= 32.

 StringUtils.trimToEmpty(null)          = ""
 StringUtils.trimToEmpty("")            = ""
 StringUtils.trimToEmpty("     ")       = ""
 StringUtils.trimToEmpty("abc")         = "abc"
 StringUtils.trimToEmpty("    abc    ") = "abc"
 

Parameters:

str - the String to be trimmed, may be null

Returns:

the trimmed String, or an empty String if null input

Since:

2.0

See Also:

• Source

equals

public static boolean equals(String cs1,
 String cs2)

Compares two Strings, returning true if they represent equal sequences of characters.

nulls are handled without exceptions. Two null references are considered to be equal. The comparison is case sensitive.

 StringUtils.equals(null, null)   = true
 StringUtils.equals(null, "abc")  = false
 StringUtils.equals("abc", null)  = false
 StringUtils.equals("abc", "abc") = true
 StringUtils.equals("abc", "ABC") = false
 

Parameters:

cs1 - the first String, may be null

cs2 - the second String, may be null

Returns:

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

See Also:

• Object.equals(Object)
• Source

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.

A null String will return null. An empty ("") String will return "".

 StringUtils.substring(null, *)   = null
 StringUtils.substring("", *)     = ""
 StringUtils.substring("abc", 0)  = "abc"
 StringUtils.substring("abc", 2)  = "c"
 StringUtils.substring("abc", 4)  = ""
 StringUtils.substring("abc", -2) = "bc"
 StringUtils.substring("abc", -4) = "abc"
 

Parameters:

str - the String to get the substring from, may be null

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, null if null String input

See Also:

• Source

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.

The returned substring starts with the character in the start position and ends before the end position. All position counting is zero-based -- i.e., to start at the beginning of the string use start = 0. Negative start and end positions can be used to specify offsets relative to the end of the String.

If start is not strictly to the left of end, "" is returned.

 StringUtils.substring(null, *, *)    = null
 StringUtils.substring("", * ,  *)    = "";
 StringUtils.substring("abc", 0, 2)   = "ab"
 StringUtils.substring("abc", 2, 0)   = ""
 StringUtils.substring("abc", 2, 4)   = "c"
 StringUtils.substring("abc", 4, 6)   = ""
 StringUtils.substring("abc", 2, 2)   = ""
 StringUtils.substring("abc", -2, -1) = "b"
 StringUtils.substring("abc", -4, 2)  = "ab"
 

Parameters:

str - the String to get the substring from, may be null

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 scharacters

Returns:

substring from start position to end position, null if null String input

See Also:

• Source

upperCase

public static String upperCase(String str)

Converts a String to upper case as per String.toUpperCase().

A null input String returns null.

 StringUtils.upperCase(null)  = null
 StringUtils.upperCase("")    = ""
 StringUtils.upperCase("aBc") = "ABC"
 

This uses "ENGLISH" as the locale.

Parameters:

str - the String to upper case, may be null

Returns:

the upper cased String, null if null String input

See Also:

• Source

lowerCase

public static String lowerCase(String str)

Converts a String to lower case as per String.toLowerCase().

A null input String returns null.

 StringUtils.lowerCase(null)  = null
 StringUtils.lowerCase("")    = ""
 StringUtils.lowerCase("aBc") = "abc"
 

This uses "ENGLISH" as the locale.

Parameters:

str - the String to lower case, may be null

Returns:

the lower cased String, null if null String input

See Also:

• Source

capitalize

public static String capitalize(String str)

Capitalizes a String changing the first character to title case as per Character.toTitleCase(int). No other characters are changed.

 StringUtils.capitalize(null)  = null
 StringUtils.capitalize("")    = ""
 StringUtils.capitalize("cat") = "Cat"
 StringUtils.capitalize("cAt") = "CAt"
 StringUtils.capitalize("'cat'") = "'cat'"
 

Parameters:

str - the String to capitalize, may be null

Returns:

the capitalized String, null if null String input

Since:

2.0

See Also:

• uncapitalize(String)
• Source

uncapitalize

public static String uncapitalize(String str)

Uncapitalizes a String, changing the first character to lower case as per Character.toLowerCase(int). No other characters are changed.

 StringUtils.uncapitalize(null)  = null
 StringUtils.uncapitalize("")    = ""
 StringUtils.uncapitalize("cat") = "cat"
 StringUtils.uncapitalize("Cat") = "cat"
 StringUtils.uncapitalize("CAT") = "cAT"
 

Parameters:

str - the String to uncapitalize, may be null

Returns:

the uncapitalized String, null if null String input

Since:

2.0

See Also:

• capitalize(String)
• Source

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(String str,
 String prefix)

Tests if this string starts with the specified prefix ignoring case considerations.

Parameters:

str - the string to be tested

prefix - the prefix

Returns:

true if the string starts with the prefix ignoring case

repeat

public static String repeat(String str,
 int repeat)

Repeat a String repeat times to form a new String.

 StringUtils.repeat(null, 2) = null
 StringUtils.repeat("", 0)   = ""
 StringUtils.repeat("", 2)   = ""
 StringUtils.repeat("a", 3)  = "aaa"
 StringUtils.repeat("ab", 2) = "abab"
 StringUtils.repeat("a", -2) = ""
 

Parameters:

str - the String to repeat, may be null

repeat - number of times to repeat str, negative treated as zero

Returns:

a new String consisting of the original String repeated, null if null String input

See Also:

• Source

repeat

public static String repeat(char ch,
 int repeat)

Returns padding using the specified delimiter repeated to a given length.

 StringUtils.repeat('e', 0)  = ""
 StringUtils.repeat('e', 3)  = "eee"
 StringUtils.repeat('e', -2) = ""
 

Note: this method does not support padding with Unicode Supplementary Characters as they require a pair of chars to be represented. If you are needing to support full I18N of your applications consider using repeat(String, int) instead.

Parameters:

ch - character to repeat

repeat - number of times to repeat char, negative treated as zero

Returns:

String with repeated character

See Also:

• repeat(String, int)
• Source

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

See Also:

• Source

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

See Also:

• Source

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

See Also:

• Source

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

See Also:

• Source

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

See Also:

• Source

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

See Also:

• Source

strip

public static String strip(String str,
 String stripChars)

Strips any of a set of characters from the start and end of a String. This is similar to String.trim() but allows the characters to be stripped to be controlled.

A null input String returns null. An empty string ("") input returns the empty string.

If the stripChars String is null, whitespace is stripped as defined by Character.isWhitespace(char).

 StringUtils.strip(null, *)          = null
 StringUtils.strip("", *)            = ""
 StringUtils.strip("abc", null)      = "abc"
 StringUtils.strip("  abc", null)    = "abc"
 StringUtils.strip("abc  ", null)    = "abc"
 StringUtils.strip(" abc ", null)    = "abc"
 StringUtils.strip("  abcyx", "xyz") = "  abc"
 

Parameters:

str - the String to remove characters from, may be null

stripChars - the characters to remove, null treated as whitespace

Returns:

the stripped String, null if null String input

See Also:

• Source

stripEnd

public static String stripEnd(String str,
 String stripChars)

Strips any of a set of characters from the end of a String.

A null input String returns null. An empty string ("") input returns the empty string.

If the stripChars String is null, whitespace is stripped as defined by Character.isWhitespace(char).

 StringUtils.stripEnd(null, *)          = null
 StringUtils.stripEnd("", *)            = ""
 StringUtils.stripEnd("abc", "")        = "abc"
 StringUtils.stripEnd("abc", null)      = "abc"
 StringUtils.stripEnd("  abc", null)    = "  abc"
 StringUtils.stripEnd("abc  ", null)    = "abc"
 StringUtils.stripEnd(" abc ", null)    = " abc"
 StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
 StringUtils.stripEnd("120.00", ".0")   = "12"
 

Parameters:

str - the String to remove characters from, may be null

stripChars - the set of characters to remove, null treated as whitespace

Returns:

the stripped String, null if null String input

See Also:

• Source

stripStart

public static String stripStart(String str,
 String stripChars)

Strips any of a set of characters from the start of a String.

A null input String returns null. An empty string ("") input returns the empty string.

If the stripChars String is null, whitespace is stripped as defined by Character.isWhitespace(char).

 StringUtils.stripStart(null, *)          = null
 StringUtils.stripStart("", *)            = ""
 StringUtils.stripStart("abc", "")        = "abc"
 StringUtils.stripStart("abc", null)      = "abc"
 StringUtils.stripStart("  abc", null)    = "abc"
 StringUtils.stripStart("abc  ", null)    = "abc  "
 StringUtils.stripStart(" abc ", null)    = "abc "
 StringUtils.stripStart("yxabc  ", "xyz") = "abc  "
 

Parameters:

str - the String to remove characters from, may be null

stripChars - the characters to remove, null treated as whitespace

Returns:

the stripped String, null if null String input

See Also:

• Source

stripToEmpty

public static String stripToEmpty(String str)

Strips whitespace from the start and end of a String returning an empty String if null input.

This is similar to trimToEmpty(String) but removes whitespace. Whitespace is defined by Character.isWhitespace(char).

 StringUtils.stripToEmpty(null)     = ""
 StringUtils.stripToEmpty("")       = ""
 StringUtils.stripToEmpty("   ")    = ""
 StringUtils.stripToEmpty("abc")    = "abc"
 StringUtils.stripToEmpty("  abc")  = "abc"
 StringUtils.stripToEmpty("abc  ")  = "abc"
 StringUtils.stripToEmpty(" abc ")  = "abc"
 StringUtils.stripToEmpty(" ab c ") = "ab c"
 

Parameters:

str - the String to be stripped, may be null

Returns:

the trimmed String, or an empty String if null input

Since:

2.0

See Also:

• Source

wrap

public static String wrap(String str,
 int wrapLength)

Wraps a single line of text, identifying words by ' '.

New lines will be separated by the system property line separator. Very long words, such as URLs will not be wrapped.

Leading spaces on a new line are stripped. Trailing spaces are not stripped.

Examples

input	wrapLength	result
null	*	null
""	*	""
"Here is one line of text that is going to be wrapped after 20 columns."	20	"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."
"Click here to jump to the commons website - http://commons.apache.org"	20	"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apache.org"
"Click here, http://commons.apache.org, to jump to the commons website"	20	"Click here,\nhttp://commons.apache.org,\nto jump to the\ncommons website"

(assuming that '\n' is the systems line separator)

Parameters:

str - the String to be word wrapped, may be null

wrapLength - the column to wrap the words at, less than 1 is treated as 1

Returns:

a line with newlines inserted, null if null input

See Also:

• Source

wrap

public static String wrap(String str,
 int wrapLength,
 String newLineStr,
 boolean wrapLongWords)

Wraps a single line of text, identifying words by ' '.

Leading spaces on a new line are stripped. Trailing spaces are not stripped.

Examples

input	wrapLength	newLineString	wrapLongWords	result
null	*	*	true/false	null
""	*	*	true/false	""
"Here is one line of text that is going to be wrapped after 20 columns."	20	"\n"	true/false	"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."
"Here is one line of text that is going to be wrapped after 20 columns."	20	"<br />"	true/false	"Here is one line of<br />text that is going< br />to be wrapped after<br />20 columns."
"Here is one line of text that is going to be wrapped after 20 columns."	20	null	true/false	"Here is one line of" + systemNewLine + "text that is going" + systemNewLine + "to be wrapped after" + systemNewLine + "20 columns."
"Click here to jump to the commons website - http://commons.apache.org"	20	"\n"	false	"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apache.org"
"Click here to jump to the commons website - http://commons.apache.org"	20	"\n"	true	"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apach\ne.org"

Parameters:

str - the String to be word wrapped, may be null

wrapLength - the column to wrap the words at, less than 1 is treated as 1

newLineStr - the string to insert for a new line, null uses the system property line separator

wrapLongWords - true if long words (such as URLs) should be wrapped

Returns:

a line with newlines inserted, null if null input

See Also:

• Source

wrap

public static String wrap(String str,
 int wrapLength,
 String newLineStr,
 boolean wrapLongWords,
 String wrapOn)

Wraps a single line of text, identifying words by wrapOn.

Leading spaces on a new line are stripped. Trailing spaces are not stripped.

Examples

input	wrapLength	newLineString	wrapLongWords	wrapOn	result
null	*	*	true/false	*	null
""	*	*	true/false	*	""
"Here is one line of text that is going to be wrapped after 20 columns."	20	"\n"	true/false	" "	"Here is one line of\ntext that is going\nto be wrapped after\n20 columns."
"Here is one line of text that is going to be wrapped after 20 columns."	20	"<br />"	true/false	" "	"Here is one line of<br />text that is going<br /> to be wrapped after<br />20 columns."
"Here is one line of text that is going to be wrapped after 20 columns."	20	null	true/false	" "	"Here is one line of" + systemNewLine + "text that is going" + systemNewLine + "to be wrapped after" + systemNewLine + "20 columns."
"Click here to jump to the commons website - http://commons.apache.org"	20	"\n"	false	" "	"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apache.org"
"Click here to jump to the commons website - http://commons.apache.org"	20	"\n"	true	" "	"Click here to jump\nto the commons\nwebsite -\nhttp://commons.apach\ne.org"
"flammable/inflammable"	20	"\n"	true	"/"	"flammable\ninflammable"

Parameters:

str - the String to be word wrapped, may be null

wrapLength - the column to wrap the words at, less than 1 is treated as 1

newLineStr - the string to insert for a new line, null uses the system property line separator

wrapLongWords - true if long words (such as URLs) should be wrapped

wrapOn - regex expression to be used as a breakable characters, if blank string is provided a space character will be used

Returns:

a line with newlines inserted, null if null input

See Also:

• Source

escapeJavaString

public static String escapeJavaString(Object object,
 String indent)

levenshteinDistance

public static int levenshteinDistance(CharSequence left,
 CharSequence right,
 int threshold)

Find the Levenshtein distance between two CharSequences if it's less than or equal to a given threshold.

This code is a copy of the limitedCompare method from Apache commons-text LevenshteinDistance.java.

This implementation follows from Algorithms on Strings, Trees and Sequences by Dan Gusfield and Chas Emerick's implementation of the Levenshtein distance algorithm from http://www.merriampark.com/ld.htm

 limitedCompare(null, *, *)             = IllegalArgumentException
 limitedCompare(*, null, *)             = IllegalArgumentException
 limitedCompare(*, *, -1)               = IllegalArgumentException
 limitedCompare("","", 0)               = 0
 limitedCompare("aaapppp", "", 8)       = 7
 limitedCompare("aaapppp", "", 7)       = 7
 limitedCompare("aaapppp", "", 6))      = -1
 limitedCompare("elephant", "hippo", 7) = 7
 limitedCompare("elephant", "hippo", 6) = -1
 limitedCompare("hippo", "elephant", 7) = 7
 limitedCompare("hippo", "elephant", 6) = -1
 

Parameters:

left - the first CharSequence, must not be null

right - the second CharSequence, must not be null

threshold - the target threshold, must not be negative

Returns:

result distance, or -1

See Also:

• LevenshteinDistance.java