org.conqat.lib.commons.string

Class StringUtils

java.lang.Object

org.conqat.lib.commons.string.StringUtils

public class StringUtils
extends java.lang.Object

A utility class providing some advanced string functionality.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DOT Dot.
static java.lang.String	EMPTY_STRING The empty string.
static java.lang.String	LINE_FEED Line feed ("\n"), platform independent.
static java.lang.String	LINE_SEPARATOR Line separator of the current platform.
static java.util.List<java.lang.Character>	MARKDOWN_ESCAPE_CHARACTERS Characters that need to be escaped in markdown.
static java.lang.String	SPACE A space.
static char	SPACE_CHAR A space character.
static java.lang.String	TAB A tab character.
static java.lang.String	TWO_SPACES Two spaces.

Constructor Summary

Constructors

Constructor and Description
StringUtils()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	addPrefix(java.lang.String string, java.lang.String separator, java.lang.String prefix) Prefixes a string with a prefix and separator if the prefix is not empty.
static java.lang.String	addSuffix(java.lang.String string, java.lang.String separator, java.lang.String suffix) Suffixes a string with a suffix and separator if the suffix is not empty.
static java.lang.String	applyAllReplacements(java.lang.String s, PairList<java.util.regex.Pattern,java.lang.String> replacements) Returns the result of applying all pattern replacements in order, each as often as possible (globally).
static java.lang.String	applyReplacement(java.lang.String s, java.util.regex.Pattern pattern, java.lang.String replacement) Returns the replacement as often as possible.
static java.util.List<java.lang.String>	asStringList(java.util.Collection<?> objects) Returns a list containing the string representations of the given collection of objects.
static java.lang.String	bytesToString(byte[] b) Converts a (UTF-8) byte array to a string.
static java.lang.String	bytesToString(byte[] b, java.nio.charset.Charset encoding) Converts a byte array to a string, assuming the given encoding, unless a byte-order mark included with the bytes implies that another encoding is actually used.
static java.lang.String	camelCaseToKebabCase(java.lang.String s) Transforms a string from camel-case to lower-case with hyphens (aka kebab case).
static java.lang.String	camelCaseToUnderscored(java.lang.String s) Transforms a string from camel-case to upper-case with underscores.
static java.lang.String	capitalize(java.lang.String string) Capitalize string.
static java.lang.String	center(java.lang.String string, int length, char c) Create a string of the given length and center the given string within it.
static int	compare(java.lang.String a, java.lang.String b) Compares two strings both of which may be null.
static java.lang.String	concat(java.lang.Iterable<?> iterable) Concatenates all elements of an iterable using the toString()-method.
static java.lang.String	concat(java.lang.Iterable<?> iterable, java.lang.String separator) Concatenates all elements of an iterable using the toString()-method, separating them with the given separator.
static java.lang.String	concat(java.util.Iterator<?> iterator, java.lang.String separator) Concatenates all elements of an iterator using the toString()-method, separating them with the given separator.
static java.lang.String	concat(java.lang.Object[] array) Concatenates all elements of an array using the toString() -method.
static java.lang.String	concat(java.lang.Object[] array, java.lang.String separator) Concatenates all elements of an array using the toString() -method, separating them with the given separator.
static java.lang.String[]	concat(java.lang.String[] array1, java.lang.String[] array2) Concatenate two string arrays.
static java.lang.String	concatWithEscapeCharacter(java.util.List<java.lang.String> data, java.lang.String delimiter) Concatenates the list of string with delimiter and add escape character if needed.
static boolean	containsAll(java.lang.String s, java.lang.String... substrings) Returns whether s contains all the given substrings.
static boolean	containsIgnoreCase(java.lang.String s1, java.lang.String s2) Returns whether s1 contains s2 ignoring case
static boolean	containsLetter(java.lang.String s) Checks if the given string contains at least one letter (checked with Character.isLetter(char)).
static boolean	containsOneOf(java.lang.String text, java.lang.Iterable<java.lang.String> strings) Test if a string contains of the provided strings.
static boolean	containsOneOf(java.lang.String text, java.lang.String... strings) Test if a string contains of the provided strings.
static int	countCharacter(java.lang.String content, char character) Returns the number of occurrences of the given character in the given string.
static int	countLines(java.lang.String content) Return number of lines in a string.
static int	countLines(java.lang.String content, boolean includeTrailingEmptyLine) Return number of lines in a string.
static java.lang.String	createUniqueName(java.lang.String baseName, java.util.Set<java.lang.String> usedNames) Creates a unique name which is not contained in the given set of names.
static java.lang.String	decapitalize(java.lang.String string) Decapitalize string.
static byte[]	decodeFromHex(java.lang.String s) Decodes a byte array from a hex string.
static java.lang.String	defaultIfNull(java.lang.String input, java.lang.String defaultValue) Returns the input string.
static java.lang.String	defaultIfNullOrEmpty(java.lang.String input, java.lang.String defaultValue) Returns the input string.
static int	editDistance(java.lang.String s, java.lang.String t) Calculates the edit distance (aka Levenshtein distance) for two strings, i.e.
static java.lang.String	emptyIfNull(java.lang.String input) Returns the input string.
static java.lang.String	encodeAsHex(byte[] data) Encodes a byte array as a hex string following the method described here: http ://stackoverflow.com/questions/9655181/convert-from-byte-array-to-hex- string-in-java
static boolean	endsWithIgnoreCase(java.lang.String string, java.lang.String suffix) Returns whether the given String ends with the specified suffix ignoring case.
static boolean	endsWithOneOf(java.lang.String string, java.lang.String... suffixes) Test if a string ends with one of the provided suffixes.
static java.lang.String	ensureEndsWith(java.lang.String s, java.lang.String suffix) Ensure that the given string ends with the given suffix, i.e.
static java.lang.String	ensureStartsWith(java.lang.String s, java.lang.String prefix) Ensure that the given string starts with the given prefix, i.e.
static boolean	equalsOneOf(java.lang.String value, java.lang.String... strings) Compares the given value to all given strings.
static java.lang.String	escapeChars(java.lang.String content, java.util.List<java.lang.Character> chars) Escapes the given chars in the content.
static java.lang.String	escapeRegexReplacementString(java.lang.String replacement) Regex replacement methods like Matcher.appendReplacement(StringBuffer, String) or String.replaceAll(String, String) treat dollar signs as group references.
static java.lang.String	fillString(int length, char c) Build a string with a specified length from a character.
static java.util.List<java.lang.String>	filterBySuffix(java.lang.String suffix, java.util.Collection<java.lang.String> strings) Filters the given collection of strings by the given suffix, i.e.
static java.lang.String	flushLeft(java.lang.String string, int length, char c) Create a sting of the given length starting with the provided string.
static java.lang.String	flushRight(java.lang.String string, int length, char c) Create a sting of the given length ending with the provided string.
static java.lang.String	format(double number, java.text.NumberFormat numberFormat) Format number with number formatter, if number formatter is null, this uses String.valueOf(double).
static java.lang.String	format(java.lang.Number number) Format number
static java.lang.String	formatAsPercentage(java.lang.Number number) Format as percentage.
static java.lang.String	fromInputStream(java.io.InputStream inputStream) Converts the given InputStream to a String with UTF-8 encoding.
static java.lang.String	generateString(int length, int seed) Generates a pseudo random string with a certain length in a deterministic, reproducable fashion.
static java.lang.String[]	generateStringArray(int length, int stringLength, int seed) Generates an array of pseudo-random strings in a deterministic, reproducable fashion.
static java.lang.String	getBeginning(java.lang.String s, int numberOfChars) Returns the beginning of the given String, retaining at most numberOfChars characters.
static java.lang.String	getFirstLine(java.lang.String string) Returns the first line of a string.
static java.lang.String	getFirstPart(java.lang.String string, char separator) Variant of getFirstPart(String, String) which accepts a single char as the separator.
static java.lang.String	getFirstPart(java.lang.String string, java.lang.String separator) Returns the first part of a String whose parts are separated by the given character.
static java.lang.String	getFirstParts(java.lang.String string, int partNumber, char separator) Returns the first n part of a string, separated by the given character.
static java.util.HashMap<java.lang.String,java.lang.String>	getKeyValuePairs(java.lang.String keyValueString) Splits a key-value string and stores it in a hash map.
static java.lang.String	getLastPart(java.lang.String string, char separator) Variant of getLastPart(String, String) which accepts a single char as the separator.
static java.lang.String	getLastPart(java.lang.String string, java.lang.String separator) Returns the last part of a String whose parts are separated by the given String.
static int	indexOf(java.lang.String[] array, java.lang.String string) Searches the elements of a string array for a string.
static int	indexOfMatch(java.lang.String string, java.util.regex.Pattern pattern) Returns the index of the first character in the given string that matches the pattern.
static boolean	isEditDistanceAtMost1(java.lang.String s, java.lang.String t) Returns whether the edit distance as calculated by editDistance(String, String), is 0 or 1.
static boolean	isEmpty(java.lang.String text) Checks if a string is empty (after trimming).
static boolean	isInteger(java.lang.String string) Checks whether the parameter contains only number literals and (optionally) starts with a '-' char.
static java.lang.String	joinDifferentLastDelimiter(java.util.List<java.lang.String> items, java.lang.String delimiter, java.lang.String lastDelimiter) Joins the elements in the given list with the given delimiter, but with a different delimiter for the very last element.
static java.lang.String	kebabCaseToCamelCase(java.lang.String name) Converts a dash-separated name (aka kebab case) to a camel-cased one.
static java.lang.String	longestCommonPrefix(java.lang.Iterable<java.lang.String> strings) Returns the longest common prefix of the strings in the list or the empty string if no common prefix exists.
static java.lang.String	longestCommonPrefix(java.lang.String s, java.lang.String t) Returns the longest common prefix of s and t
static java.lang.String	longestCommonSuffix(java.lang.String s, java.lang.String t) Returns the longest common suffix of s and t
static java.util.List<java.lang.String>	lowercaseList(java.util.Collection<java.lang.String> strings) Returns a list that contains all entries of the original list as lowercase strings.
static java.lang.String	normalizeLineSeparatorsPlatformIndependent(java.lang.String string) Replace all linebreaks in string with a line feed symbol (\n), platform independent.
static java.lang.String	normalizeLineSeparatorsPlatformSpecific(java.lang.String string) Replace all linebreaks in string with the platform-specific line separator (LINE_SEPARATOR).
static java.lang.String	nullIfEmpty(java.lang.String input) Returns null if the input string is empty (after trimming) or null.
static java.lang.String	obtainStackTrace(java.lang.Throwable throwable) Convert stack trace of a Throwable to a string.
static java.lang.String	pluralize(java.lang.String string, int count) Returns the string itself, if count is 1.
static java.lang.String	prefixLines(java.lang.String string, java.lang.String prefix, boolean prefixFirstLine) Prefix all lines of a string.
static java.lang.String	randomString(int length) Generates a random string with a certain length.
static java.lang.String	randomString(int length, java.util.Random random) Performs the actal creation of the random string using the given randomizer.
static java.lang.String[]	randomStringArray(int length, int stringLength) Generates an array of random strings.
static java.lang.String	removeAll(java.lang.String string, java.lang.String... stringsToRemove) Removes all occurrences of the specified strings from the given string.
static java.lang.String	removeDoubleQuotes(java.lang.String string) Removes double quotes from beginning and end (if present) and returns the new string.
static java.lang.String	removeLastPart(java.lang.String string, char separator) Returns the beginning of a String, cutting off the last part which is separated by the given character.
static java.lang.String	removeSingleQuotes(java.lang.String string) Removes single quotes from beginning and end (if present) and returns the new string.
static java.lang.String	removeWhitespace(java.lang.String content) Removes whitespace from a string.
static java.lang.String	removeWhitespaceAtBeginningOfLine(java.lang.String content) Removes all whitespace at the beginning of each line in the given string.
static java.lang.String	repeat(java.lang.String s, int times) Repeats a String
static java.lang.String	replaceFromMap(java.lang.String string, java.util.Map<java.lang.String,java.lang.String> replacements) Replaces all occurrences of keys of the given map in the given string with the associated value in that map.
static java.lang.String	replaceLineBreaks(java.lang.String string, java.lang.String symbol) Replace all linebreaks in string by a specified symbol.
static java.lang.String	retainHeadLines(java.lang.String text, int numberOfLines) Returns a truncated string that contains only the first x lines of the given text.
static java.lang.String	reverse(java.lang.String s) Reverse a string
static java.lang.String	safeToString(java.lang.Object value) Object.toString() with null check.
static Pair<java.lang.String,java.lang.String>	splitAtLast(java.lang.String string, char separator) Splits the string at the last occurence of separator.
static java.lang.Character[]	splitChars(java.lang.String s) Splits the given string into an array of Characters.
static java.lang.String[]	splitLines(java.lang.String content) Split string in lines.
static java.util.List<java.lang.String>	splitLinesAsList(java.lang.String content) Split string in lines.
static java.util.List<java.lang.String>	splitLinesAsList(java.lang.String content, boolean includeTrailingEmptyLine) Split string in lines.
static java.util.List<java.lang.String>	splitTopLevel(java.lang.String input, char separator, char levelStart, char levelEnd) Splits a string at every top-level occurrence of the separator character.
static java.util.List<java.lang.String>	splitWithEscapeCharacter(java.lang.String data, java.lang.String delimiter) Splits the delimited string with considering escaped delimiters.
static boolean	startsWithIgnoreCase(java.lang.String string, java.lang.String prefix) Returns whether the given string starts with the prefix ignoring case, i.e.
static boolean	startsWithOneOf(java.lang.String string, java.lang.Iterable<java.lang.String> prefixes) Test if a string starts with one of the provided prefixes.
static boolean	startsWithOneOf(java.lang.String string, java.lang.String... prefixes) Test if a string starts with one of the provided prefixes.
static byte[]	stringToBytes(java.lang.String s) Converts a string to a (UTF-8) byte representation.
static java.lang.String	stripDigits(java.lang.String string) Strips all digits from the given String.
static java.lang.String	stripPrefix(java.lang.String string, java.lang.String prefix) Remove prefix from a string.
static java.lang.String	stripPrefixIgnoreCase(java.lang.String string, java.lang.String prefix) Remove prefix from a string.
static java.lang.String	stripSuffix(java.lang.String string, java.lang.String suffix) Remove suffix from a string.
static java.lang.String	stripTrailingDigits(java.lang.String string) Strips all trailing digits from the end of the given String.
static java.lang.String	surroundWith(java.lang.String s, java.lang.String prefix, java.lang.String suffix) Adds a prefix and a suffix to the given string.
static java.lang.String	toFirstUpper(java.lang.String s) Converts the given String to a String where the first character is in upper case and all other characters are in lower case
static java.io.InputStream	toInputStream(java.lang.String string) Converts the given String to an InputStream with UTF-8 encoding.
static java.lang.String	toString(java.util.Map<?,?> map) Create string representation of a map.
static java.lang.String	toString(java.util.Map<?,?> map, java.lang.String indent) Create string representation of a map.
static java.lang.String[]	toStringArray(java.lang.Object[] array) Converts the given Object array into a String array by invoking toString on each non-null element.
static <T> java.util.List<java.lang.String>	toStrings(java.util.Collection<T> objects) Converts the given objects into a string list by invoking Object.toString() on each non-null element.
static java.lang.String	truncate(java.lang.String string, int length, java.lang.String suffix) Truncates the given string (if necessary) by removing characters from the end and attaching the suffix such that the resulting string has at most length characters.
static java.lang.String	unEscapeChars(java.lang.String content, java.util.List<java.lang.Character> chars) Un-escapes the given chars in the content.
static java.lang.String	wrapLongLines(java.lang.String s, int maxLineLength) This method splits the input string into words (delimited by whitespace) and returns a string whose words are separated by single spaces and whose lines are not longer than the given length (unless a very long word occurs)).

Methods inherited from class java.lang.Object

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

Field Detail

LINE_SEPARATOR

public static final java.lang.String LINE_SEPARATOR

Line separator of the current platform.

LINE_FEED

public static final java.lang.String LINE_FEED

Line feed ("\n"), platform independent.

See Also:

Constant Field Values

EMPTY_STRING

public static final java.lang.String EMPTY_STRING

The empty string. Use StringUtils.EMPTY_STRING instead of "" (our Java coding guidelines)

1. Use StringUtils.EMPTY_STRING instead of an empty string literal ("") to make it clear that this is intentionally empty. Using "" may leave the reader in doubt whether this is something unfinished (e.g. "" used temporally until something meaningful is filled in) or intentionally the empty String. Making it explicit removes this problem)
2. On most JVMs, using "" allocates a new String object per class in which it used. Using EMPTY_STRING re-uses a single object and safes a few bytes. Note
3. Makes " " and "" better distinguishable.

See Also:

Constant Field Values

SPACE

public static final java.lang.String SPACE

A space.

See Also:

Constant Field Values

SPACE_CHAR

public static final char SPACE_CHAR

A space character.

See Also:

Constant Field Values

TAB

public static final java.lang.String TAB

A tab character.

See Also:

Constant Field Values

TWO_SPACES

public static final java.lang.String TWO_SPACES

Two spaces.

See Also:

Constant Field Values

DOT

public static final java.lang.String DOT

Dot.

See Also:

Constant Field Values

MARKDOWN_ESCAPE_CHARACTERS

public static final java.util.List<java.lang.Character> MARKDOWN_ESCAPE_CHARACTERS

Characters that need to be escaped in markdown. use with escapeChars(String, List) and unEscapeChars(String, List)

Constructor Detail

StringUtils

public StringUtils()

Method Detail

center

public static java.lang.String center(java.lang.String string,
                                      int length,
                                      char c)

Create a string of the given length and center the given string within it. Left and right areas are filled by the character provided.

Parameters:

string - The input string.

length - The length of the string to be returned.

c - The character to surround the input string with.

Returns:

the new string or, if the string is longer than the specified length, the original string.

See Also:

flushLeft(String, int, char), flushRight(String, int, char)

compare

public static int compare(java.lang.String a,
                          java.lang.String b)

Compares two strings both of which may be null. A string which is null is always smaller than the other string, except for both strings being null.

Parameters:

a - The string which is compared to the second string.

b - The string which is compared to the first string.

Returns:

Returns 0 if both strings are null, -1 if only the first string is null, and 1 if only the second string is null. If both strings are not null, returns the result of the usual string comparison.

concat

public static java.lang.String concat(java.lang.Iterable<?> iterable)

Concatenates all elements of an iterable using the toString()-method.

Parameters:

iterable - the iterable

Returns:

a concatenation, separated by spaces

concat

public static java.lang.String concat(java.lang.Iterable<?> iterable,
                                      java.lang.String separator)

Concatenates all elements of an iterable using the toString()-method, separating them with the given separator.

Parameters:

iterable - the iterable containing the strings

separator - the separator to place between the strings, may be null

Returns:

a concatenation of the string in the iterable or null if iterable was null. If the iterable is of size 0 the empty string is returned.

concat

public static java.lang.String concat(java.util.Iterator<?> iterator,
                                      java.lang.String separator)

Concatenates all elements of an iterator using the toString()-method, separating them with the given separator.

Parameters:

iterator - the Iterator containing the strings

separator - the separator to place between the strings, may be null

Returns:

a concatenation of the string in the iterator or null if iterator was null. If the iterator has no elements the empty string is returned.

concat

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

Concatenates all elements of an array using the toString() -method.

Parameters:

array - the array containing the strings

Returns:

a concatenation of the string separated by spaces

concat

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

Concatenates all elements of an array using the toString() -method, separating them with the given separator.

Parameters:

array - the array

separator - the separator to place between the strings, may be null

Returns:

a concatenation of the string in the array or null if array was null. If array is of length 0 the empty string is returned.

joinDifferentLastDelimiter

public static java.lang.String joinDifferentLastDelimiter(java.util.List<java.lang.String> items,
                                                          java.lang.String delimiter,
                                                          java.lang.String lastDelimiter)

Joins the elements in the given list with the given delimiter, but with a different delimiter for the very last element.

This could, for example, be used if you want to create a String "a, b and c" from a list containing "a", "b" and "c".

concat

public static java.lang.String[] concat(java.lang.String[] array1,
                                        java.lang.String[] array2)

Concatenate two string arrays.

fillString

public static java.lang.String fillString(int length,
                                          char c)

Build a string with a specified length from a character.

Parameters:

length - The length of the string.

c - The character.

Returns:

The string.

flushLeft

public static java.lang.String flushLeft(java.lang.String string,
                                         int length,
                                         char c)

Create a sting of the given length starting with the provided string. Remaining characters are filled with the provided character.

Parameters:

string - The input string.

length - The length of the string to be returned.

c - The character to fill the string.

Returns:

the new string or, if the string is longer than the specified length, the original string.

See Also:

flushRight(String, int, char), center(String, int, char)

flushRight

public static java.lang.String flushRight(java.lang.String string,
                                          int length,
                                          char c)

Create a sting of the given length ending with the provided string. Remaining characters are filled with the provided character.

Parameters:

string - The input string.

length - The length of the string to be returned.

c - The character to fill the string.

Returns:

the new string or, if the string is longer than the specified length, the original string.

See Also:

flushLeft(String, int, char), center(String, int, char)

format

public static java.lang.String format(java.lang.Number number)

Format number

formatAsPercentage

public static java.lang.String formatAsPercentage(java.lang.Number number)

Format as percentage.

getFirstLine

public static java.lang.String getFirstLine(java.lang.String string)

Returns the first line of a string.

getFirstParts

public static java.lang.String getFirstParts(java.lang.String string,
                                             int partNumber,
                                             char separator)

Returns the first n part of a string, separated by the given character. E.g., getStringParts("edu.tum.cs", 2, '.') gives: "edu.tum".

Parameters:

string - the base string

partNumber - number of parts

separator - the separator character

getKeyValuePairs

public static java.util.HashMap<java.lang.String,java.lang.String> getKeyValuePairs(java.lang.String keyValueString)

Splits a key-value string and stores it in a hash map. The string must have the following format:

key=value[,key=value]*

If the string is null null is returned.

Parameters:

keyValueString - with format described above

Returns:

a hash map containing the key-values-pairs.

getFirstPart

public static java.lang.String getFirstPart(java.lang.String string,
                                            java.lang.String separator)

Returns the first part of a String whose parts are separated by the given character. E.g., getFirstPart("foo@bar@acme", '@') gives "foo".

Parameters:

string - the String

separator - separation character

Returns:

the first part of the String, or the original String if the separation character is not found.

getFirstPart

public static java.lang.String getFirstPart(java.lang.String string,
                                            char separator)

Variant of getFirstPart(String, String) which accepts a single char as the separator.

See Also:

getFirstPart(String, String)

getLastPart

public static java.lang.String getLastPart(java.lang.String string,
                                           java.lang.String separator)

Returns the last part of a String whose parts are separated by the given String. E.g., getLastPart("org.conqat##lib.commons.string##StringUtils", "##") gives "StringUtils". If separator is the empty string, this method returns the empty string.

Parameters:

string - the String

separator - separation String

Returns:

the last part of the String, or the original String if the separation String is not found.

getLastPart

public static java.lang.String getLastPart(java.lang.String string,
                                           char separator)

Variant of getLastPart(String, String) which accepts a single char as the separator.

See Also:

getLastPart(String, String)

splitAtLast

public static Pair<java.lang.String,java.lang.String> splitAtLast(java.lang.String string,
                                                                  char separator)

Splits the string at the last occurence of separator. If the separator does not occur, the second string in the returned pair is empty. E.g. splitAtLast(foo.bar.baz, '.') gives ("foo.bar", "baz).

indexOf

public static int indexOf(java.lang.String[] array,
                          java.lang.String string)

Searches the elements of a string array for a string. Strings are trimmed.

Parameters:

array - the array to search

string - the search string

Returns:

the index of the element where the string was found or -1 if string wasn't found.

isEmpty

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

Checks if a string is empty (after trimming).

Parameters:

text - the string to check.

Returns:

true if string is empty or null, false otherwise.

containsLetter

public static boolean containsLetter(java.lang.String s)

Checks if the given string contains at least one letter (checked with Character.isLetter(char)).

containsIgnoreCase

public static boolean containsIgnoreCase(java.lang.String s1,
                                         java.lang.String s2)

Returns whether s1 contains s2 ignoring case

containsAll

public static boolean containsAll(java.lang.String s,
                                  java.lang.String... substrings)

Returns whether s contains all the given substrings.

randomString

public static java.lang.String randomString(int length)

Generates a random string with a certain length. The string consists of characters with ASCII code between 33 and 126.

Parameters:

length - the length of the random string

Returns:

the random string

randomString

public static java.lang.String randomString(int length,
                                            java.util.Random random)

Performs the actal creation of the random string using the given randomizer.

randomStringArray

public static java.lang.String[] randomStringArray(int length,
                                                   int stringLength)

Generates an array of random strings.

Parameters:

length - number of strings

stringLength - length of each string

Returns:

the randomly generated array.

generateString

public static java.lang.String generateString(int length,
                                              int seed)

Generates a pseudo random string with a certain length in a deterministic, reproducable fashion.

Parameters:

length - the length of the pseudo-random string

seed - seed value for the random number generator used for the generation of the pseudo-random string. If the same seed value is used, the same pseudo-random string is generated.

generateStringArray

public static java.lang.String[] generateStringArray(int length,
                                                     int stringLength,
                                                     int seed)

Generates an array of pseudo-random strings in a deterministic, reproducable fashion.

Parameters:

length - number of strings

stringLength - length of each string

seed - seed value for the random number generator used for the generation of the pseudo-random string. If the same seed value is used, the same pseudo-random string array is generated.

Returns:

the randomly generated array.

removeLastPart

public static java.lang.String removeLastPart(java.lang.String string,
                                              char separator)

Returns the beginning of a String, cutting off the last part which is separated by the given character. E.g., removeLastPart("org.conqat.lib.commons.string.StringUtils", '.') gives "org.conqat.lib.commons.string".

Parameters:

string - the String

separator - separation character

Returns:

the String without the last part, or the original string (i.e., the same object) if the separation character is not found.

replaceFromMap

public static java.lang.String replaceFromMap(java.lang.String string,
                                              java.util.Map<java.lang.String,java.lang.String> replacements)

Replaces all occurrences of keys of the given map in the given string with the associated value in that map. The given map may be null, in which case the original string is returned unchanged. This method is semantically the same as calling String.replace(CharSequence, CharSequence) for each of the entries in the map, but may be significantly faster for many replacements performed on a short string, since String.replace(CharSequence, CharSequence) uses regular expressions internally and results in many String object allocations when applied iteratively. The order in which replacements are applied depends on the order of the map's entry set.

removeAll

public static java.lang.String removeAll(java.lang.String string,
                                         java.lang.String... stringsToRemove)

Removes all occurrences of the specified strings from the given string.

normalizeLineSeparatorsPlatformSpecific

public static java.lang.String normalizeLineSeparatorsPlatformSpecific(java.lang.String string)

Replace all linebreaks in string with the platform-specific line separator (LINE_SEPARATOR).

Returns:

a string with linebreaks replaced by the line separator of the current platform

normalizeLineSeparatorsPlatformIndependent

public static java.lang.String normalizeLineSeparatorsPlatformIndependent(java.lang.String string)

Replace all linebreaks in string with a line feed symbol (\n), platform independent.

Returns:

a string with linebreaks replaced by LINE_FEED.

replaceLineBreaks

public static java.lang.String replaceLineBreaks(java.lang.String string,
                                                 java.lang.String symbol)

Replace all linebreaks in string by a specified symbol.

Returns:

a string with line breaks replaced.

splitLines

public static java.lang.String[] splitLines(java.lang.String content)

Split string in lines. For the the empty string and null an array of length zero is returned.

See Also:

splitLinesAsList(String)

countCharacter

public static int countCharacter(java.lang.String content,
                                 char character)

Returns the number of occurrences of the given character in the given string.

countLines

public static int countLines(java.lang.String content)

Return number of lines in a string.

countLines

public static int countLines(java.lang.String content,
                             boolean includeTrailingEmptyLine)

Return number of lines in a string.

splitLinesAsList

public static java.util.List<java.lang.String> splitLinesAsList(java.lang.String content)

Split string in lines. For the the empty string and null an empty list is returned.

See Also:

splitLines(String)

splitLinesAsList

public static java.util.List<java.lang.String> splitLinesAsList(java.lang.String content,
                                                                boolean includeTrailingEmptyLine)

Split string in lines. For the the empty string and null an empty list is returned.

See Also:

splitLines(String)

addPrefix

public static java.lang.String addPrefix(java.lang.String string,
                                         java.lang.String separator,
                                         java.lang.String prefix)

Prefixes a string with a prefix and separator if the prefix is not empty.

addSuffix

public static java.lang.String addSuffix(java.lang.String string,
                                         java.lang.String separator,
                                         java.lang.String suffix)

Suffixes a string with a suffix and separator if the suffix is not empty.

stripPrefix

public static java.lang.String stripPrefix(java.lang.String string,
                                           java.lang.String prefix)

Remove prefix from a string.

Parameters:

string - the string

prefix - the prefix

Returns:

the string without the prefix or the original string if it does not start with the prefix.

stripPrefixIgnoreCase

public static java.lang.String stripPrefixIgnoreCase(java.lang.String string,
                                                     java.lang.String prefix)

Remove prefix from a string. This ignores casing, i.e. stripPrefixIgnoreCase("C:/Programs/", "c:/programs/notepad.exe") will return "notepad.exe".

Parameters:

string - the string

prefix - the prefix

Returns:

the string without the prefix or the original string if it does not start with the prefix.

stripSuffix

public static java.lang.String stripSuffix(java.lang.String string,
                                           java.lang.String suffix)

Remove suffix from a string.

Parameters:

string - the string

suffix - the suffix

Returns:

the string without the suffix or the original string if it does not end with the suffix.

stripDigits

public static java.lang.String stripDigits(java.lang.String string)

Strips all digits from the given String.

stripTrailingDigits

public static java.lang.String stripTrailingDigits(java.lang.String string)

Strips all trailing digits from the end of the given String.

toString

public static java.lang.String toString(java.util.Map<?,?> map)

Create string representation of a map.

toString

public static java.lang.String toString(java.util.Map<?,?> map,
                                        java.lang.String indent)

Create string representation of a map.

Parameters:

map - the map

indent - a line indent

obtainStackTrace

public static java.lang.String obtainStackTrace(java.lang.Throwable throwable)

Convert stack trace of a Throwable to a string.

startsWithOneOf

public static boolean startsWithOneOf(java.lang.String string,
                                      java.lang.String... prefixes)

Test if a string starts with one of the provided prefixes. Returns false if the list of prefixes is empty. This should only be used for short lists of prefixes.

startsWithOneOf

public static boolean startsWithOneOf(java.lang.String string,
                                      java.lang.Iterable<java.lang.String> prefixes)

Test if a string starts with one of the provided prefixes. Returns false if the list of prefixes is empty. This should only be used for short lists of prefixes. The given list must not be null.

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(java.lang.String string,
                                           java.lang.String prefix)

Returns whether the given string starts with the prefix ignoring case, i.e. startsWithIgnoreCase("foobar", "Foo") will return true.

containsOneOf

public static boolean containsOneOf(java.lang.String text,
                                    java.lang.String... strings)

Test if a string contains of the provided strings. Returns false if the list of strings is empty. This should only be used for short lists of strings.

containsOneOf

public static boolean containsOneOf(java.lang.String text,
                                    java.lang.Iterable<java.lang.String> strings)

Test if a string contains of the provided strings. Returns false if the list of strings is empty. This should only be used for short lists of strings.

endsWithIgnoreCase

public static boolean endsWithIgnoreCase(java.lang.String string,
                                         java.lang.String suffix)

Returns whether the given String ends with the specified suffix ignoring case.

endsWithOneOf

public static boolean endsWithOneOf(java.lang.String string,
                                    java.lang.String... suffixes)

Test if a string ends with one of the provided suffixes. Returns false if the list of prefixes is empty. This should only be used for short lists of suffixes.

prefixLines

public static java.lang.String prefixLines(java.lang.String string,
                                           java.lang.String prefix,
                                           boolean prefixFirstLine)

Prefix all lines of a string. This also replaces line breaks with the platform-specific line-separator.

Parameters:

string - the string to prefix

prefix - the prefix to add

prefixFirstLine - a flag that indicates if the first line should be prefixed or not.

splitChars

public static java.lang.Character[] splitChars(java.lang.String s)

Splits the given string into an array of Characters. This is mostly used for testing purposes, if an array of certain objects is needed.

capitalize

public static java.lang.String capitalize(java.lang.String string)

Capitalize string.

decapitalize

public static java.lang.String decapitalize(java.lang.String string)

Decapitalize string.

wrapLongLines

public static java.lang.String wrapLongLines(java.lang.String s,
                                             int maxLineLength)

This method splits the input string into words (delimited by whitespace) and returns a string whose words are separated by single spaces and whose lines are not longer than the given length (unless a very long word occurs)).

longestCommonPrefix

public static java.lang.String longestCommonPrefix(java.lang.String s,
                                                   java.lang.String t)

Returns the longest common prefix of s and t

longestCommonSuffix

public static java.lang.String longestCommonSuffix(java.lang.String s,
                                                   java.lang.String t)

Returns the longest common suffix of s and t

reverse

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

Reverse a string

longestCommonPrefix

public static java.lang.String longestCommonPrefix(java.lang.Iterable<java.lang.String> strings)

Returns the longest common prefix of the strings in the list or the empty string if no common prefix exists.

removeWhitespace

public static java.lang.String removeWhitespace(java.lang.String content)

Removes whitespace from a string.

removeWhitespaceAtBeginningOfLine

public static java.lang.String removeWhitespaceAtBeginningOfLine(java.lang.String content)

Removes all whitespace at the beginning of each line in the given string.

createUniqueName

public static java.lang.String createUniqueName(java.lang.String baseName,
                                                java.util.Set<java.lang.String> usedNames)

Creates a unique name which is not contained in the given set of names. If possible the given base name is directly returned, otherwise it is extended by a number.

camelCaseToKebabCase

public static java.lang.String camelCaseToKebabCase(java.lang.String s)

Transforms a string from camel-case to lower-case with hyphens (aka kebab case).

kebabCaseToCamelCase

public static java.lang.String kebabCaseToCamelCase(java.lang.String name)

Converts a dash-separated name (aka kebab case) to a camel-cased one.

camelCaseToUnderscored

public static java.lang.String camelCaseToUnderscored(java.lang.String s)

Transforms a string from camel-case to upper-case with underscores.

encodeAsHex

public static java.lang.String encodeAsHex(byte[] data)

Encodes a byte array as a hex string following the method described here: http ://stackoverflow.com/questions/9655181/convert-from-byte-array-to-hex- string-in-java

decodeFromHex

public static byte[] decodeFromHex(java.lang.String s)

Decodes a byte array from a hex string.

format

public static java.lang.String format(double number,
                                      java.text.NumberFormat numberFormat)

Format number with number formatter, if number formatter is null, this uses String.valueOf(double).

escapeRegexReplacementString

public static java.lang.String escapeRegexReplacementString(java.lang.String replacement)

Regex replacement methods like Matcher.appendReplacement(StringBuffer, String) or String.replaceAll(String, String) treat dollar signs as group references. This method escapes replacement strings so that dollar signs are treated as literals.

stringToBytes

public static byte[] stringToBytes(java.lang.String s)

Converts a string to a (UTF-8) byte representation. This returns null on a null input.

bytesToString

public static java.lang.String bytesToString(byte[] b)

Converts a (UTF-8) byte array to a string. This returns null on a null input.

bytesToString

public static java.lang.String bytesToString(byte[] b,
                                             java.nio.charset.Charset encoding)

Converts a byte array to a string, assuming the given encoding, unless a byte-order mark included with the bytes implies that another encoding is actually used.

This method returns null on a null input.

asStringList

public static java.util.List<java.lang.String> asStringList(java.util.Collection<?> objects)

Returns a list containing the string representations of the given collection of objects. String.valueOf(java.lang.Object) is used to convert each object. null values are included, i.e., the resulting list is guaranteed to have the size of the initial collection.

filterBySuffix

public static java.util.List<java.lang.String> filterBySuffix(java.lang.String suffix,
                                                              java.util.Collection<java.lang.String> strings)

Filters the given collection of strings by the given suffix, i.e. the resulting list contains only those strings that end with this suffix.

toStrings

public static <T> java.util.List<java.lang.String> toStrings(java.util.Collection<T> objects)

Converts the given objects into a string list by invoking Object.toString() on each non-null element. For null entries in the input, the output will contain a null entry as well.

toStringArray

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

Converts the given Object array into a String array by invoking toString on each non-null element. For null entries in the input array, the output will contain a null entry as well

toInputStream

public static java.io.InputStream toInputStream(java.lang.String string)

Converts the given String to an InputStream with UTF-8 encoding.

fromInputStream

public static java.lang.String fromInputStream(java.io.InputStream inputStream)
                                        throws java.io.IOException

Converts the given InputStream to a String with UTF-8 encoding.

Throws:

java.io.IOException

truncate

public static java.lang.String truncate(java.lang.String string,
                                        int length,
                                        java.lang.String suffix)

Truncates the given string (if necessary) by removing characters from the end and attaching the suffix such that the resulting string has at most length characters. length must be >= suffix.length();

editDistance

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

Calculates the edit distance (aka Levenshtein distance) for two strings, i.e. the number of insert, delete or replace operations required to transform one string into the other. The running time is O(n*m) and the space complexity is O(n+m), where n/m are the lengths of the strings. Note that due to the high running time, for long strings the Diff class should be used, that has a more efficient algorithm, but only for insert/delete (not replace operation). Although this is a clean reimplementation, the basic algorithm is explained here: http://en.wikipedia.org/wiki/Levenshtein_distance# Iterative_with_two_matrix_rows

isEditDistanceAtMost1

public static boolean isEditDistanceAtMost1(java.lang.String s,
                                            java.lang.String t)

Returns whether the edit distance as calculated by editDistance(String, String), is 0 or 1. This implementation is significantly more efficient compared to actually calculating the edit distance and runs in O(n+m). The idea is that with at most one change, the start and end of both strings must be the same, to traverse from start and end to the first difference. If the distance between both pointers is at most one, the edit distance is at most one as well.

lowercaseList

public static java.util.List<java.lang.String> lowercaseList(java.util.Collection<java.lang.String> strings)

Returns a list that contains all entries of the original list as lowercase strings. Does not operate in-place!

defaultIfNull

public static java.lang.String defaultIfNull(java.lang.String input,
                                             java.lang.String defaultValue)

Returns the input string. Returns the provided default value in case the input is null.

defaultIfNullOrEmpty

public static java.lang.String defaultIfNullOrEmpty(java.lang.String input,
                                                    java.lang.String defaultValue)

Returns the input string. Returns the provided default value in case the input is null or the empty string.

emptyIfNull

public static java.lang.String emptyIfNull(java.lang.String input)

Returns the input string. Returns EMPTY_STRING in case the input is null.

splitTopLevel

public static java.util.List<java.lang.String> splitTopLevel(java.lang.String input,
                                                             char separator,
                                                             char levelStart,
                                                             char levelEnd)

Splits a string at every top-level occurrence of the separator character. This can be useful e.g. for splitting type parameter lists. "String,Map<String,Integer>,Map<String,Map<String,Integer>>" split at ',' with levelStart = '<' and levelEnd = '>' would result in ["String","Map<String,Integer>","Map<String,Map<String,Integer>>"] If there is no separator char, use the levelStart char. In this case, separator chars are included in the output. splitTopLevel("((a))(b)", '(', '(', ')' ) = ["", "((a))", "(b)"] Can also be used to split columns from a CSV line where values can be quoted splitTopLevel("\"a\";\";\";c", ';', '"', '"' ) = ["\"a\"", "\";\"", "c"]

Parameters:

input - The input string.

separator - The separator character.

levelStart - The character that starts a new level.

levelEnd - The character that ends a level.

Returns:

The input string split at every top-level separator.

Throws:

java.lang.AssertionError - If the numbers for opening and closing characters in the input string differ.

ensureEndsWith

public static java.lang.String ensureEndsWith(java.lang.String s,
                                              java.lang.String suffix)

Ensure that the given string ends with the given suffix, i.e. if it does not have the given suffix, the returned string is s + suffix.

ensureStartsWith

public static java.lang.String ensureStartsWith(java.lang.String s,
                                                java.lang.String prefix)

Ensure that the given string starts with the given prefix, i.e. if it does not have the given prefix, it is prepended to the string.

concatWithEscapeCharacter

public static java.lang.String concatWithEscapeCharacter(java.util.List<java.lang.String> data,
                                                         java.lang.String delimiter)

Concatenates the list of string with delimiter and add escape character if needed. For example following list { "asd,rtz", "rrr", "rrr" } with delimiter as comma(,) will produce the following comma(,) delimited sting "asd\\,rtz,rrr,rrr"

splitWithEscapeCharacter

public static java.util.List<java.lang.String> splitWithEscapeCharacter(java.lang.String data,
                                                                        java.lang.String delimiter)

Splits the delimited string with considering escaped delimiters. For example following comma(,) delimited string "asd\\,rtz,rrr,rrr" will produce the list { "asd,rtz", "rrr", "rrr" }

applyAllReplacements

public static java.lang.String applyAllReplacements(java.lang.String s,
                                                    PairList<java.util.regex.Pattern,java.lang.String> replacements)

Returns the result of applying all pattern replacements in order, each as often as possible (globally).

applyReplacement

public static java.lang.String applyReplacement(java.lang.String s,
                                                java.util.regex.Pattern pattern,
                                                java.lang.String replacement)

Returns the replacement as often as possible. This is the equivalent of String.replaceAll(String, String), but accepting a Pattern instead of a regex string.

nullIfEmpty

public static java.lang.String nullIfEmpty(java.lang.String input)

Returns null if the input string is empty (after trimming) or null. Otherwise, the input is returned unaltered.

isInteger

public static boolean isInteger(java.lang.String string)

Checks whether the parameter contains only number literals and (optionally) starts with a '-' char. Returns false if the string is null or empty.

indexOfMatch

public static int indexOfMatch(java.lang.String string,
                               java.util.regex.Pattern pattern)

Returns the index of the first character in the given string that matches the pattern. The pattern is applied to single characters, so it makes no sense to supply patterns that would match on longer character sequences.

escapeChars

public static java.lang.String escapeChars(java.lang.String content,
                                           java.util.List<java.lang.Character> chars)

Escapes the given chars in the content. Prepends a "\" before each occurrence of the chars. Special whitespace chars ('\t','\b','\n','\r', and '\f') are replaced by "\t",... . Existing occurrences of "\t",... are prepended with a "\".

unEscapeChars

public static java.lang.String unEscapeChars(java.lang.String content,
                                             java.util.List<java.lang.Character> chars)

Un-escapes the given chars in the content. Replaces each occurrence of \a with "a" (if "a" is in chars). Whitespace escape sequences (\t, \b, \n, \r, and \f) are replaced by their actual values ('\t',...) . Existing occurrences of \\t,... are replaced with \t.

getBeginning

public static java.lang.String getBeginning(java.lang.String s,
                                            int numberOfChars)

Returns the beginning of the given String, retaining at most numberOfChars characters. In case the String is short or equals to numberOfChars, the supplied String is returned unchanged. Otherwise the String is truncated to numberOfChars characters and suffixed with ...

toFirstUpper

public static java.lang.String toFirstUpper(java.lang.String s)

Converts the given String to a String where the first character is in upper case and all other characters are in lower case

pluralize

public static java.lang.String pluralize(java.lang.String string,
                                         int count)

Returns the string itself, if count is 1. Otherwise returns the string with appended "s".

surroundWith

public static java.lang.String surroundWith(java.lang.String s,
                                            java.lang.String prefix,
                                            java.lang.String suffix)

Adds a prefix and a suffix to the given string.

equalsOneOf

public static boolean equalsOneOf(java.lang.String value,
                                  java.lang.String... strings)

Compares the given value to all given strings. This loops through the supplied string array. If the array is larger or you already have the Strings in a Collection, use Collection.contains(..). Consider putting the arguments into a Collection constant.

Returns:

if one string equals the value.

removeDoubleQuotes

public static java.lang.String removeDoubleQuotes(java.lang.String string)

Removes double quotes from beginning and end (if present) and returns the new string.

removeSingleQuotes

public static java.lang.String removeSingleQuotes(java.lang.String string)

Removes single quotes from beginning and end (if present) and returns the new string.

repeat

public static java.lang.String repeat(java.lang.String s,
                                      int times)

Repeats a String

Parameters:

s - the String to repeat

times - number of times the string gets repeated

Returns:

the repeated String

safeToString

public static java.lang.String safeToString(java.lang.Object value)

Object.toString() with null check.

Parameters:

value - object to stringify

Returns:

string representation or EMPTY_STRING if value is null.

retainHeadLines

public static java.lang.String retainHeadLines(java.lang.String text,
                                               int numberOfLines)

Returns a truncated string that contains only the first x lines of the given text.