org.springframework.util

Class StringUtils

java.lang.Object

org.springframework.util.StringUtils

public abstract class StringUtils
extends java.lang.Object

Miscellaneous String utility methods.

Mainly for internal use within the framework; consider Apache's Commons Lang for a more comprehensive suite of String utilities.

This class delivers some simple functionality that should really be provided by the core Java String and StringBuilder classes. It also provides easy-to-use methods to convert between delimited strings, such as CSV strings, and collections and arrays.

Since:

16 April 2001

Author:

Rod Johnson, Juergen Hoeller, Keith Donald, Rob Harrop, Rick Evans, Arjen Poutsma, Sam Brannen, Brian Clozel

Field Summary

Fields

Modifier and Type	Field and Description
private static java.lang.String	CURRENT_PATH
private static char	EXTENSION_SEPARATOR
private static java.lang.String	FOLDER_SEPARATOR
private static java.lang.String	TOP_PATH
private static java.lang.String	WINDOWS_FOLDER_SEPARATOR

Constructor Summary

Constructors

Constructor and Description
StringUtils()

Method Summary

Modifier and Type	Method and Description
static java.lang.String[]	addStringToArray(java.lang.String[] array, java.lang.String str) Append the given String to the given String array, returning a new array consisting of the input array contents plus the given String.
static java.lang.String	applyRelativePath(java.lang.String path, java.lang.String relativePath) Apply the given relative path to the given Java resource path, assuming standard Java folder separation (i.e.
static java.lang.String	arrayToCommaDelimitedString(java.lang.Object[] arr) Convert a String array into a comma delimited String (i.e., CSV).
static java.lang.String	arrayToDelimitedString(java.lang.Object[] arr, java.lang.String delim) Convert a String array into a delimited String (e.g.
static java.lang.String	capitalize(java.lang.String str) Capitalize a String, changing the first letter to upper case as per Character.toUpperCase(char).
private static java.lang.String	changeFirstCharacterCase(java.lang.String str, boolean capitalize)
static java.lang.String	cleanPath(java.lang.String path) Normalize the path by suppressing sequences like "path/.." and inner simple dots.
static java.lang.String	collectionToCommaDelimitedString(java.util.Collection<?> coll) Convert a Collection into a delimited String (e.g., CSV).
static java.lang.String	collectionToDelimitedString(java.util.Collection<?> coll, java.lang.String delim) Convert a Collection into a delimited String (e.g.
static java.lang.String	collectionToDelimitedString(java.util.Collection<?> coll, java.lang.String delim, java.lang.String prefix, java.lang.String suffix) Convert a Collection to a delimited String (e.g.
static java.util.Set<java.lang.String>	commaDelimitedListToSet(java.lang.String str) Convert a comma delimited list (e.g., a row from a CSV file) into a set.
static java.lang.String[]	commaDelimitedListToStringArray(java.lang.String str) Convert a comma delimited list (e.g., a row from a CSV file) into an array of strings.
static java.lang.String[]	concatenateStringArrays(java.lang.String[] array1, java.lang.String[] array2) Concatenate the given String arrays into one, with overlapping array elements included twice.
private static boolean	containsText(java.lang.CharSequence str)
static boolean	containsWhitespace(java.lang.CharSequence str) Check whether the given CharSequence contains any whitespace characters.
static boolean	containsWhitespace(java.lang.String str) Check whether the given String contains any whitespace characters.
static int	countOccurrencesOf(java.lang.String str, java.lang.String sub) Count the occurrences of the substring sub in string str.
static java.lang.String	delete(java.lang.String inString, java.lang.String pattern) Delete all occurrences of the given substring.
static java.lang.String	deleteAny(java.lang.String inString, java.lang.String charsToDelete) Delete any character in a given String.
static java.lang.String[]	delimitedListToStringArray(java.lang.String str, java.lang.String delimiter) Take a String that is a delimited list and convert it into a String array.
static java.lang.String[]	delimitedListToStringArray(java.lang.String str, java.lang.String delimiter, java.lang.String charsToDelete) Take a String that is a delimited list and convert it into a String array.
static boolean	endsWithIgnoreCase(java.lang.String str, java.lang.String suffix) Test if the given String ends with the specified suffix, ignoring upper/lower case.
static java.lang.String	getFilename(java.lang.String path) Extract the filename from the given Java resource path, e.g.
static java.lang.String	getFilenameExtension(java.lang.String path) Extract the filename extension from the given Java resource path, e.g.
static boolean	hasLength(java.lang.CharSequence str) Check that the given CharSequence is neither null nor of length 0.
static boolean	hasLength(java.lang.String str) Check that the given String is neither null nor of length 0.
static boolean	hasText(java.lang.CharSequence str) Check whether the given CharSequence contains actual text.
static boolean	hasText(java.lang.String str) Check whether the given String contains actual text.
static boolean	isEmpty(java.lang.Object str) Check whether the given String is empty.
static java.lang.String[]	mergeStringArrays(java.lang.String[] array1, java.lang.String[] array2) Deprecated. as of 4.3.15, in favor of manual merging via LinkedHashSet (with every entry included at most once, even entries within the first array)
static java.util.Locale	parseLocale(java.lang.String localeValue) Parse the given String value into a Locale, accepting the Locale.toString() format as well as BCP 47 language tags.
static java.util.Locale	parseLocaleString(java.lang.String localeString) Parse the given String representation into a Locale.
private static java.util.Locale	parseLocaleTokens(java.lang.String localeString, java.lang.String[] tokens)
static java.util.TimeZone	parseTimeZoneString(java.lang.String timeZoneString) Parse the given timeZoneString value into a TimeZone.
static boolean	pathEquals(java.lang.String path1, java.lang.String path2) Compare two paths after normalization of them.
static java.lang.String	quote(java.lang.String str) Quote the given String with single quotes.
static java.lang.Object	quoteIfString(java.lang.Object obj) Turn the given Object into a String with single quotes if it is a String; keeping the Object as-is else.
static java.lang.String[]	removeDuplicateStrings(java.lang.String[] array) Remove duplicate strings from the given array.
static java.lang.String	replace(java.lang.String inString, java.lang.String oldPattern, java.lang.String newPattern) Replace all occurrences of a substring within a string with another string.
static java.lang.String[]	sortStringArray(java.lang.String[] array) Sort the given String array if necessary.
static java.lang.String[]	split(java.lang.String toSplit, java.lang.String delimiter) Split a String at the first occurrence of the delimiter.
static java.util.Properties	splitArrayElementsIntoProperties(java.lang.String[] array, java.lang.String delimiter) Take an array of strings and split each element based on the given delimiter.
static java.util.Properties	splitArrayElementsIntoProperties(java.lang.String[] array, java.lang.String delimiter, java.lang.String charsToDelete) Take an array of strings and split each element based on the given delimiter.
static boolean	startsWithIgnoreCase(java.lang.String str, java.lang.String prefix) Test if the given String starts with the specified prefix, ignoring upper/lower case.
static java.lang.String	stripFilenameExtension(java.lang.String path) Strip the filename extension from the given Java resource path, e.g.
static boolean	substringMatch(java.lang.CharSequence str, int index, java.lang.CharSequence substring) Test whether the given string matches the given substring at the given index.
private static java.lang.String[]	tokenizeLocaleSource(java.lang.String localeSource)
static java.lang.String[]	tokenizeToStringArray(java.lang.String str, java.lang.String delimiters) Tokenize the given String into a String array via a StringTokenizer.
static java.lang.String[]	tokenizeToStringArray(java.lang.String str, java.lang.String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) Tokenize the given String into a String array via a StringTokenizer.
static java.lang.String	toLanguageTag(java.util.Locale locale) Deprecated. as of 5.0.4, in favor of Locale.toLanguageTag()
static java.lang.String[]	toStringArray(java.util.Collection<java.lang.String> collection) Copy the given Collection into a String array.
static java.lang.String[]	toStringArray(java.util.Enumeration<java.lang.String> enumeration) Copy the given Enumeration into a String array.
static java.lang.String	trimAllWhitespace(java.lang.String str) Trim all whitespace from the given String: leading, trailing, and in between characters.
static java.lang.String[]	trimArrayElements(java.lang.String[] array) Trim the elements of the given String array, calling String.trim() on each of them.
static java.lang.String	trimLeadingCharacter(java.lang.String str, char leadingCharacter) Trim all occurrences of the supplied leading character from the given String.
static java.lang.String	trimLeadingWhitespace(java.lang.String str) Trim leading whitespace from the given String.
static java.lang.String	trimTrailingCharacter(java.lang.String str, char trailingCharacter) Trim all occurrences of the supplied trailing character from the given String.
static java.lang.String	trimTrailingWhitespace(java.lang.String str) Trim trailing whitespace from the given String.
static java.lang.String	trimWhitespace(java.lang.String str) Trim leading and trailing whitespace from the given String.
static java.lang.String	uncapitalize(java.lang.String str) Uncapitalize a String, changing the first letter to lower case as per Character.toLowerCase(char).
static java.lang.String	unqualify(java.lang.String qualifiedName) Unqualify a string qualified by a '.' dot character.
static java.lang.String	unqualify(java.lang.String qualifiedName, char separator) Unqualify a string qualified by a separator character.
static java.lang.String	uriDecode(java.lang.String source, java.nio.charset.Charset charset) Decode the given encoded URI component value.
private static void	validateLocalePart(java.lang.String localePart)

Methods inherited from class java.lang.Object

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

Field Detail

FOLDER_SEPARATOR

private static final java.lang.String FOLDER_SEPARATOR

See Also:

Constant Field Values

WINDOWS_FOLDER_SEPARATOR

private static final java.lang.String WINDOWS_FOLDER_SEPARATOR

See Also:

Constant Field Values

TOP_PATH

private static final java.lang.String TOP_PATH

See Also:

Constant Field Values

CURRENT_PATH

private static final java.lang.String CURRENT_PATH

See Also:

Constant Field Values

EXTENSION_SEPARATOR

private static final char EXTENSION_SEPARATOR

See Also:

Constant Field Values

Constructor Detail

StringUtils

public StringUtils()

Method Detail

isEmpty

public static boolean isEmpty(@Nullable
                              java.lang.Object str)

Check whether the given String is empty.

This method accepts any Object as an argument, comparing it to null and the empty String. As a consequence, this method will never return true for a non-null non-String object.

The Object signature is useful for general attribute handling code that commonly deals with Strings but generally has to iterate over Objects since attributes may e.g. be primitive value objects as well.

Parameters:

str - the candidate String

Since:

3.2.1

hasLength

public static boolean hasLength(@Nullable
                                java.lang.CharSequence str)

Check that the given CharSequence is neither null nor of length 0.

Note: this method returns true for a CharSequence that purely consists of whitespace.

 StringUtils.hasLength(null) = false
 StringUtils.hasLength("") = false
 StringUtils.hasLength(" ") = true
 StringUtils.hasLength("Hello") = true
 

Parameters:

str - the CharSequence to check (may be null)

Returns:

true if the CharSequence is not null and has length

See Also:

hasText(String)

hasLength

public static boolean hasLength(@Nullable
                                java.lang.String str)

Check that the given String is neither null nor of length 0.

Note: this method returns true for a String that purely consists of whitespace.

Parameters:

str - the String to check (may be null)

Returns:

true if the String is not null and has length

See Also:

hasLength(CharSequence), hasText(String)

hasText

public static boolean hasText(@Nullable
                              java.lang.CharSequence str)

Check whether the given CharSequence contains actual text.

More specifically, this method returns true if the CharSequence is not null, its length is greater than 0, and it contains at least one non-whitespace character.

 StringUtils.hasText(null) = false
 StringUtils.hasText("") = false
 StringUtils.hasText(" ") = false
 StringUtils.hasText("12345") = true
 StringUtils.hasText(" 12345 ") = true
 

Parameters:

str - the CharSequence to check (may be null)

Returns:

true if the CharSequence is not null, its length is greater than 0, and it does not contain whitespace only

See Also:

Character.isWhitespace(char)

hasText

public static boolean hasText(@Nullable
                              java.lang.String str)

Check whether the given String contains actual text.

More specifically, this method returns true if the String is not null, its length is greater than 0, and it contains at least one non-whitespace character.

Parameters:

str - the String to check (may be null)

Returns:

true if the String is not null, its length is greater than 0, and it does not contain whitespace only

See Also:

hasText(CharSequence)

containsText

private static boolean containsText(java.lang.CharSequence str)

containsWhitespace

public static boolean containsWhitespace(@Nullable
                                         java.lang.CharSequence str)

Check whether the given CharSequence contains any whitespace characters.

Parameters:

str - the CharSequence to check (may be null)

Returns:

true if the CharSequence is not empty and contains at least 1 whitespace character

See Also:

Character.isWhitespace(char)

containsWhitespace

public static boolean containsWhitespace(@Nullable
                                         java.lang.String str)

Check whether the given String contains any whitespace characters.

Parameters:

str - the String to check (may be null)

Returns:

true if the String is not empty and contains at least 1 whitespace character

See Also:

containsWhitespace(CharSequence)

trimWhitespace

public static java.lang.String trimWhitespace(java.lang.String str)

Trim leading and trailing whitespace from the given String.

Parameters:

str - the String to check

Returns:

the trimmed String

See Also:

Character.isWhitespace(char)

trimAllWhitespace

public static java.lang.String trimAllWhitespace(java.lang.String str)

Trim all whitespace from the given String: leading, trailing, and in between characters.

Parameters:

str - the String to check

Returns:

the trimmed String

See Also:

Character.isWhitespace(char)

trimLeadingWhitespace

public static java.lang.String trimLeadingWhitespace(java.lang.String str)

Trim leading whitespace from the given String.

Parameters:

str - the String to check

Returns:

the trimmed String

See Also:

Character.isWhitespace(char)

trimTrailingWhitespace

public static java.lang.String trimTrailingWhitespace(java.lang.String str)

Trim trailing whitespace from the given String.

Parameters:

str - the String to check

Returns:

the trimmed String

See Also:

Character.isWhitespace(char)

trimLeadingCharacter

public static java.lang.String trimLeadingCharacter(java.lang.String str,
                                                    char leadingCharacter)

Trim all occurrences of the supplied leading character from the given String.

Parameters:

str - the String to check

leadingCharacter - the leading character to be trimmed

Returns:

the trimmed String

trimTrailingCharacter

public static java.lang.String trimTrailingCharacter(java.lang.String str,
                                                     char trailingCharacter)

Trim all occurrences of the supplied trailing character from the given String.

Parameters:

str - the String to check

trailingCharacter - the trailing character to be trimmed

Returns:

the trimmed String

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(@Nullable
                                           java.lang.String str,
                                           @Nullable
                                           java.lang.String prefix)

Test if the given String starts with the specified prefix, ignoring upper/lower case.

Parameters:

str - the String to check

prefix - the prefix to look for

See Also:

String.startsWith(java.lang.String, int)

endsWithIgnoreCase

public static boolean endsWithIgnoreCase(@Nullable
                                         java.lang.String str,
                                         @Nullable
                                         java.lang.String suffix)

Test if the given String ends with the specified suffix, ignoring upper/lower case.

Parameters:

str - the String to check

suffix - the suffix to look for

See Also:

String.endsWith(java.lang.String)

substringMatch

public static boolean substringMatch(java.lang.CharSequence str,
                                     int index,
                                     java.lang.CharSequence substring)

Test whether the given string matches the given substring at the given index.

Parameters:

str - the original string (or StringBuilder)

index - the index in the original string to start matching against

substring - the substring to match at the given index

countOccurrencesOf

public static int countOccurrencesOf(java.lang.String str,
                                     java.lang.String sub)

Count the occurrences of the substring sub in string str.

Parameters:

str - string to search in

sub - string to search for

replace

public static java.lang.String replace(java.lang.String inString,
                                       java.lang.String oldPattern,
                                       @Nullable
                                       java.lang.String newPattern)

Replace all occurrences of a substring within a string with another string.

Parameters:

inString - String to examine

oldPattern - String to replace

newPattern - String to insert

Returns:

a String with the replacements

delete

public static java.lang.String delete(java.lang.String inString,
                                      java.lang.String pattern)

Delete all occurrences of the given substring.

Parameters:

inString - the original String

pattern - the pattern to delete all occurrences of

Returns:

the resulting String

deleteAny

public static java.lang.String deleteAny(java.lang.String inString,
                                         @Nullable
                                         java.lang.String charsToDelete)

Delete any character in a given String.

Parameters:

inString - the original String

charsToDelete - a set of characters to delete. E.g. "az\n" will delete 'a's, 'z's and new lines.

Returns:

the resulting String

quote

@Nullable
public static java.lang.String quote(@Nullable
                                               java.lang.String str)

Quote the given String with single quotes.

Parameters:

str - the input String (e.g. "myString")

Returns:

the quoted String (e.g. "'myString'"), or null if the input was null

quoteIfString

@Nullable
public static java.lang.Object quoteIfString(@Nullable
                                                       java.lang.Object obj)

Turn the given Object into a String with single quotes if it is a String; keeping the Object as-is else.

Parameters:

obj - the input Object (e.g. "myString")

Returns:

the quoted String (e.g. "'myString'"), or the input object as-is if not a String

unqualify

public static java.lang.String unqualify(java.lang.String qualifiedName)

Unqualify a string qualified by a '.' dot character. For example, "this.name.is.qualified", returns "qualified".

Parameters:

qualifiedName - the qualified name

unqualify

public static java.lang.String unqualify(java.lang.String qualifiedName,
                                         char separator)

Unqualify a string qualified by a separator character. For example, "this:name:is:qualified" returns "qualified" if using a ':' separator.

Parameters:

qualifiedName - the qualified name

separator - the separator

capitalize

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

Capitalize a String, changing the first letter to upper case as per Character.toUpperCase(char). No other letters are changed.

Parameters:

str - the String to capitalize

Returns:

the capitalized String

uncapitalize

public static java.lang.String uncapitalize(java.lang.String str)

Uncapitalize a String, changing the first letter to lower case as per Character.toLowerCase(char). No other letters are changed.

Parameters:

str - the String to uncapitalize

Returns:

the uncapitalized String

changeFirstCharacterCase

private static java.lang.String changeFirstCharacterCase(java.lang.String str,
                                                         boolean capitalize)

getFilename

@Nullable
public static java.lang.String getFilename(@Nullable
                                                     java.lang.String path)

Extract the filename from the given Java resource path, e.g. "mypath/myfile.txt" -> "myfile.txt".

Parameters:

path - the file path (may be null)

Returns:

the extracted filename, or null if none

getFilenameExtension

@Nullable
public static java.lang.String getFilenameExtension(@Nullable
                                                              java.lang.String path)

Extract the filename extension from the given Java resource path, e.g. "mypath/myfile.txt" -> "txt".

Parameters:

path - the file path (may be null)

Returns:

the extracted filename extension, or null if none

stripFilenameExtension

public static java.lang.String stripFilenameExtension(java.lang.String path)

Strip the filename extension from the given Java resource path, e.g. "mypath/myfile.txt" -> "mypath/myfile".

Parameters:

path - the file path

Returns:

the path with stripped filename extension

applyRelativePath

public static java.lang.String applyRelativePath(java.lang.String path,
                                                 java.lang.String relativePath)

Apply the given relative path to the given Java resource path, assuming standard Java folder separation (i.e. "/" separators).

Parameters:

path - the path to start from (usually a full file path)

relativePath - the relative path to apply (relative to the full file path above)

Returns:

the full file path that results from applying the relative path

cleanPath

public static java.lang.String cleanPath(java.lang.String path)

Normalize the path by suppressing sequences like "path/.." and inner simple dots.

The result is convenient for path comparison. For other uses, notice that Windows separators ("\") are replaced by simple slashes.

Parameters:

path - the original path

Returns:

the normalized path

pathEquals

public static boolean pathEquals(java.lang.String path1,
                                 java.lang.String path2)

Compare two paths after normalization of them.

Parameters:

path1 - first path for comparison

path2 - second path for comparison

Returns:

whether the two paths are equivalent after normalization

uriDecode

public static java.lang.String uriDecode(java.lang.String source,
                                         java.nio.charset.Charset charset)

Decode the given encoded URI component value. Based on the following rules:

• Alphanumeric characters "a" through "z", "A" through "Z", and "0" through "9" stay the same.
• Special characters "-", "_", ".", and "*" stay the same.
• A sequence "%<i>xy</i>" is interpreted as a hexadecimal representation of the character.

Parameters:

source - the encoded String

charset - the character set

Returns:

the decoded value

Throws:

java.lang.IllegalArgumentException - when the given source contains invalid encoded sequences

Since:

5.0

See Also:

URLDecoder.decode(String, String)

parseLocale

@Nullable
public static java.util.Locale parseLocale(java.lang.String localeValue)

Parse the given String value into a Locale, accepting the Locale.toString() format as well as BCP 47 language tags.

Parameters:

localeValue - the locale value: following either Locale's toString() format ("en", "en_UK", etc), also accepting spaces as separators (as an alternative to underscores), or BCP 47 (e.g. "en-UK") as specified by Locale.forLanguageTag(java.lang.String) on Java 7+

Returns:

a corresponding Locale instance, or null if none

Throws:

java.lang.IllegalArgumentException - in case of an invalid locale specification

Since:

5.0.4

See Also:

parseLocaleString(java.lang.String), Locale.forLanguageTag(java.lang.String)

parseLocaleString

@Nullable
public static java.util.Locale parseLocaleString(java.lang.String localeString)

Parse the given String representation into a Locale.

For many parsing scenarios, this is an inverse operation of Locale's toString, in a lenient sense. This method does not aim for strict Locale design compliance; it is rather specifically tailored for typical Spring parsing needs.

Note: This delegate does not accept the BCP 47 language tag format. Please use parseLocale(java.lang.String) for lenient parsing of both formats.

Parameters:

localeString - the locale String: following Locale's toString() format ("en", "en_UK", etc), also accepting spaces as separators (as an alternative to underscores)

Returns:

a corresponding Locale instance, or null if none

Throws:

java.lang.IllegalArgumentException - in case of an invalid locale specification

tokenizeLocaleSource

private static java.lang.String[] tokenizeLocaleSource(java.lang.String localeSource)

parseLocaleTokens

@Nullable
private static java.util.Locale parseLocaleTokens(java.lang.String localeString,
                                                            java.lang.String[] tokens)

validateLocalePart

private static void validateLocalePart(java.lang.String localePart)

toLanguageTag

@Deprecated
public static java.lang.String toLanguageTag(java.util.Locale locale)

Deprecated. as of 5.0.4, in favor of Locale.toLanguageTag()

Determine the RFC 3066 compliant language tag, as used for the HTTP "Accept-Language" header.

Parameters:

locale - the Locale to transform to a language tag

Returns:

the RFC 3066 compliant language tag as String

parseTimeZoneString

public static java.util.TimeZone parseTimeZoneString(java.lang.String timeZoneString)

Parse the given timeZoneString value into a TimeZone.

Parameters:

timeZoneString - the time zone String, following TimeZone.getTimeZone(String) but throwing IllegalArgumentException in case of an invalid time zone specification

Returns:

a corresponding TimeZone instance

Throws:

java.lang.IllegalArgumentException - in case of an invalid time zone specification

toStringArray

public static java.lang.String[] toStringArray(@Nullable
                                               java.util.Collection<java.lang.String> collection)

Copy the given Collection into a String array.

The Collection must contain String elements only.

Parameters:

collection - the Collection to copy (potentially null or empty)

Returns:

the resulting String array

toStringArray

public static java.lang.String[] toStringArray(@Nullable
                                               java.util.Enumeration<java.lang.String> enumeration)

Copy the given Enumeration into a String array.

The Enumeration must contain String elements only.

Parameters:

enumeration - the Enumeration to copy (potentially null or empty)

Returns:

the resulting String array

addStringToArray

public static java.lang.String[] addStringToArray(@Nullable
                                                  java.lang.String[] array,
                                                  java.lang.String str)

Append the given String to the given String array, returning a new array consisting of the input array contents plus the given String.

Parameters:

array - the array to append to (can be null)

str - the String to append

Returns:

the new array (never null)

concatenateStringArrays

@Nullable
public static java.lang.String[] concatenateStringArrays(@Nullable
                                                                   java.lang.String[] array1,
                                                                   @Nullable
                                                                   java.lang.String[] array2)

Concatenate the given String arrays into one, with overlapping array elements included twice.

The order of elements in the original arrays is preserved.

Parameters:

array1 - the first array (can be null)

array2 - the second array (can be null)

Returns:

the new array (null if both given arrays were null)

mergeStringArrays

@Deprecated
 @Nullable
public static java.lang.String[] mergeStringArrays(@Nullable
                                                                          java.lang.String[] array1,
                                                                          @Nullable
                                                                          java.lang.String[] array2)

Deprecated. as of 4.3.15, in favor of manual merging via LinkedHashSet (with every entry included at most once, even entries within the first array)

Merge the given String arrays into one, with overlapping array elements only included once.

The order of elements in the original arrays is preserved (with the exception of overlapping elements, which are only included on their first occurrence).

Parameters:

array1 - the first array (can be null)

array2 - the second array (can be null)

Returns:

the new array (null if both given arrays were null)

sortStringArray

public static java.lang.String[] sortStringArray(java.lang.String[] array)

Sort the given String array if necessary.

Parameters:

array - the original array (potentially empty)

Returns:

the array in sorted form (never null)

trimArrayElements

public static java.lang.String[] trimArrayElements(java.lang.String[] array)

Trim the elements of the given String array, calling String.trim() on each of them.

Parameters:

array - the original String array (potentially empty)

Returns:

the resulting array (of the same size) with trimmed elements

removeDuplicateStrings

public static java.lang.String[] removeDuplicateStrings(java.lang.String[] array)

Remove duplicate strings from the given array.

As of 4.2, it preserves the original order, as it uses a LinkedHashSet.

Parameters:

array - the String array (potentially empty)

Returns:

an array without duplicates, in natural sort order

split

@Nullable
public static java.lang.String[] split(@Nullable
                                                 java.lang.String toSplit,
                                                 @Nullable
                                                 java.lang.String delimiter)

Split a String at the first occurrence of the delimiter. Does not include the delimiter in the result.

Parameters:

toSplit - the string to split (potentially null or empty)

delimiter - to split the string up with (potentially null or empty)

Returns:

a two element array with index 0 being before the delimiter, and index 1 being after the delimiter (neither element includes the delimiter); or null if the delimiter wasn't found in the given input String

splitArrayElementsIntoProperties

@Nullable
public static java.util.Properties splitArrayElementsIntoProperties(java.lang.String[] array,
                                                                              java.lang.String delimiter)

Take an array of strings and split each element based on the given delimiter. A Properties instance is then generated, with the left of the delimiter providing the key, and the right of the delimiter providing the value.

Will trim both the key and value before adding them to the Properties.

Parameters:

array - the array to process

delimiter - to split each element using (typically the equals symbol)

Returns:

a Properties instance representing the array contents, or null if the array to process was null or empty

splitArrayElementsIntoProperties

@Nullable
public static java.util.Properties splitArrayElementsIntoProperties(java.lang.String[] array,
                                                                              java.lang.String delimiter,
                                                                              @Nullable
                                                                              java.lang.String charsToDelete)

Take an array of strings and split each element based on the given delimiter. A Properties instance is then generated, with the left of the delimiter providing the key, and the right of the delimiter providing the value.

Will trim both the key and value before adding them to the Properties instance.

Parameters:

array - the array to process

delimiter - to split each element using (typically the equals symbol)

charsToDelete - one or more characters to remove from each element prior to attempting the split operation (typically the quotation mark symbol), or null if no removal should occur

Returns:

a Properties instance representing the array contents, or null if the array to process was null or empty

tokenizeToStringArray

public static java.lang.String[] tokenizeToStringArray(@Nullable
                                                       java.lang.String str,
                                                       java.lang.String delimiters)

Tokenize the given String into a String array via a StringTokenizer.

Trims tokens and omits empty tokens.

The given delimiters string can consist of any number of delimiter characters. Each of those characters can be used to separate tokens. A delimiter is always a single character; for multi-character delimiters, consider using delimitedListToStringArray(java.lang.String, java.lang.String).

Parameters:

str - the String to tokenize (potentially null or empty)

delimiters - the delimiter characters, assembled as a String (each of the characters is individually considered as a delimiter)

Returns:

an array of the tokens

See Also:

StringTokenizer, String.trim(), delimitedListToStringArray(java.lang.String, java.lang.String)

tokenizeToStringArray

public static java.lang.String[] tokenizeToStringArray(@Nullable
                                                       java.lang.String str,
                                                       java.lang.String delimiters,
                                                       boolean trimTokens,
                                                       boolean ignoreEmptyTokens)

Tokenize the given String into a String array via a StringTokenizer.

The given delimiters string can consist of any number of delimiter characters. Each of those characters can be used to separate tokens. A delimiter is always a single character; for multi-character delimiters, consider using delimitedListToStringArray(java.lang.String, java.lang.String).

Parameters:

str - the String to tokenize (potentially null or empty)

delimiters - the delimiter characters, assembled as a String (each of the characters is individually considered as a delimiter)

trimTokens - trim the tokens via String.trim()

ignoreEmptyTokens - omit empty tokens from the result array (only applies to tokens that are empty after trimming; StringTokenizer will not consider subsequent delimiters as token in the first place).

Returns:

an array of the tokens

See Also:

StringTokenizer, String.trim(), delimitedListToStringArray(java.lang.String, java.lang.String)

delimitedListToStringArray

public static java.lang.String[] delimitedListToStringArray(@Nullable
                                                            java.lang.String str,
                                                            @Nullable
                                                            java.lang.String delimiter)

Take a String that is a delimited list and convert it into a String array.

A single delimiter may consist of more than one character, but it will still be considered as a single delimiter string, rather than as bunch of potential delimiter characters, in contrast to tokenizeToStringArray(java.lang.String, java.lang.String).

Parameters:

str - the input String (potentially null or empty)

delimiter - the delimiter between elements (this is a single delimiter, rather than a bunch individual delimiter characters)

Returns:

an array of the tokens in the list

See Also:

tokenizeToStringArray(java.lang.String, java.lang.String)

delimitedListToStringArray

public static java.lang.String[] delimitedListToStringArray(@Nullable
                                                            java.lang.String str,
                                                            @Nullable
                                                            java.lang.String delimiter,
                                                            @Nullable
                                                            java.lang.String charsToDelete)

Take a String that is a delimited list and convert it into a String array.

A single delimiter may consist of more than one character, but it will still be considered as a single delimiter string, rather than as bunch of potential delimiter characters, in contrast to tokenizeToStringArray(java.lang.String, java.lang.String).

Parameters:

str - the input String (potentially null or empty)

delimiter - the delimiter between elements (this is a single delimiter, rather than a bunch individual delimiter characters)

charsToDelete - a set of characters to delete; useful for deleting unwanted line breaks: e.g. "\r\n\f" will delete all new lines and line feeds in a String

Returns:

an array of the tokens in the list

See Also:

tokenizeToStringArray(java.lang.String, java.lang.String)

commaDelimitedListToStringArray

public static java.lang.String[] commaDelimitedListToStringArray(@Nullable
                                                                 java.lang.String str)

Convert a comma delimited list (e.g., a row from a CSV file) into an array of strings.

Parameters:

str - the input String (potentially null or empty)

Returns:

an array of strings, or the empty array in case of empty input

commaDelimitedListToSet

public static java.util.Set<java.lang.String> commaDelimitedListToSet(@Nullable
                                                                      java.lang.String str)

Convert a comma delimited list (e.g., a row from a CSV file) into a set.

Note that this will suppress duplicates, and as of 4.2, the elements in the returned set will preserve the original order in a LinkedHashSet.

Parameters:

str - the input String (potentially null or empty)

Returns:

a set of String entries in the list

See Also:

removeDuplicateStrings(String[])

collectionToDelimitedString

public static java.lang.String collectionToDelimitedString(@Nullable
                                                           java.util.Collection<?> coll,
                                                           java.lang.String delim,
                                                           java.lang.String prefix,
                                                           java.lang.String suffix)

Convert a Collection to a delimited String (e.g. CSV).

Useful for toString() implementations.

Parameters:

coll - the Collection to convert (potentially null or empty)

delim - the delimiter to use (typically a ",")

prefix - the String to start each element with

suffix - the String to end each element with

Returns:

the delimited String

collectionToDelimitedString

public static java.lang.String collectionToDelimitedString(@Nullable
                                                           java.util.Collection<?> coll,
                                                           java.lang.String delim)

Convert a Collection into a delimited String (e.g. CSV).

Useful for toString() implementations.

Parameters:

coll - the Collection to convert (potentially null or empty)

delim - the delimiter to use (typically a ",")

Returns:

the delimited String

collectionToCommaDelimitedString

public static java.lang.String collectionToCommaDelimitedString(@Nullable
                                                                java.util.Collection<?> coll)

Convert a Collection into a delimited String (e.g., CSV).

Useful for toString() implementations.

Parameters:

coll - the Collection to convert (potentially null or empty)

Returns:

the delimited String

arrayToDelimitedString

public static java.lang.String arrayToDelimitedString(@Nullable
                                                      java.lang.Object[] arr,
                                                      java.lang.String delim)

Convert a String array into a delimited String (e.g. CSV).

Useful for toString() implementations.

Parameters:

arr - the array to display (potentially null or empty)

delim - the delimiter to use (typically a ",")

Returns:

the delimited String

arrayToCommaDelimitedString

public static java.lang.String arrayToCommaDelimitedString(@Nullable
                                                           java.lang.Object[] arr)

Convert a String array into a comma delimited String (i.e., CSV).

Useful for toString() implementations.

Parameters:

arr - the array to display (potentially null or empty)

Returns:

the delimited String