Apache Log4j API 2.22.0 · org.apache.logging.log4j.util.Strings

Modifier and Type	Field and Description
private static final String	COMMA_DELIMITED_RE
public static final String	EMPTY The empty string.
public static final String[]	EMPTY_ARRAY The empty array.
public static final String	LINE_SEPARATOR OS-dependent line separator, defaults to `"\n"` if the system property `""line.separator"` cannot be read.
private static final ThreadLocal<StringBuilder>	tempStr

Access	Constructor and Description
private	Strings()

Method Summary

Modifier and Type	Method and Description
public static String	Returns: the concatenated String. concat(final String the first string. str1, final String the second string. str2) Concatenates 2 Strings without allocation.
public static String	Returns: `"str"` dquote(final String a String str) Returns a double quoted string.
public static boolean	Returns: `true` if the String is `null`, empty, or all characters are `Character#isWhitespace(char)` isBlank(final String the String to check, may be `null` s) Checks if a String is blank.
public static boolean	Returns: `true` if the CharSequence is empty or null isEmpty(final CharSequence the CharSequence to check, may be null cs) Checks if a CharSequence is empty ("") or null.
public static boolean	Returns: `true` if the String is non-`null` and has content after being trimmed. isNotBlank(final String the String to check, may be `null` s) Checks if a String is not blank.
public static boolean	Returns: `true` if the CharSequence is not empty and not null isNotEmpty(final CharSequence the CharSequence to check, may be null cs) Checks if a CharSequence is not empty ("") and not null.
public static String	Returns: the joined String, `null` if null iterator input join(final Iterable<?> the `Iterable` providing the values to join together, may be null iterable, final char the separator character to use separator) Joins the elements of the provided `Iterable` into a single String containing the provided elements.
public static String	Returns: the joined String, `null` if null iterator input join(final Iterator<?> the `Iterator` of values to join together, may be null iterator, final char the separator character to use separator) Joins the elements of the provided `Iterator` into a single String containing the provided elements.
public static String	Returns: the leftmost characters, `null` if null String input left(final String the String to get the leftmost characters from, may be null str, final int the length of the required String len) Gets the leftmost `len` characters of a String.
public static String	Returns: `'str'` quote(final String a String str) Returns a quoted string.
public static String	Returns: the new string repeat(final String input string str, final int the repetition count count) Creates a new string repeating given `str` `count` times.
public static String[]	splitList(final String string)
public static String	Returns: a new string toRootLowerCase(final String The string to upper case. str) Shorthand for `str.toLowerCase(Locale.ROOT);`
public static String	Returns: a new string toRootUpperCase(final String The string to lower case. str) Shorthand for `str.toUpperCase(Locale.ROOT);`
public static String	Returns: the trimmed String, `null` if only chars <= 32, empty or null String input trimToNull(final String the String to be trimmed, may be null str) Removes control characters (char <= 32) from both ends of this String returning `null` if the String is empty ("") after the trim or if it is `null`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

COMMA_DELIMITED_RE	back to summary
private static final String COMMA_DELIMITED_RE

EMPTY	back to summary
public static final String EMPTY The empty string.

EMPTY_ARRAY	back to summary
public static final String[] EMPTY_ARRAY The empty array.

LINE_SEPARATOR	back to summary
public static final String LINE_SEPARATOR OS-dependent line separator, defaults to `"\n"` if the system property `""line.separator"` cannot be read.

tempStr	back to summary
private static final ThreadLocal<StringBuilder> tempStr

Strings	back to summary
private Strings()

Method Detail

concat	back to summary
public static String concat(final String str1, final String str2) Concatenates 2 Strings without allocation. Parameters str1:String the first string. str2:String the second string. Returns:String the concatenated String.

concat

back to summary

public static String concat(final String str1, final String str2)

Concatenates 2 Strings without allocation.

Parameters

str1:String: the first string.
str2:String: the second string.

Returns:String

the concatenated String.

dquote back to summary

dquote	back to summary
public static String dquote(final String str) Returns a double quoted string. Parameters str:String a String Returns:String `"str"`

public static String dquote(final String str)

Returns a double quoted string.

Parameters

str:String: a String

Returns:String

"str"

isBlank back to summary

isBlank	back to summary
public static boolean isBlank(final String s) Checks if a String is blank. A blank string is one that is either `null`, empty, or all characters are `Character#isWhitespace(char)`. Parameters s:String the String to check, may be `null` Returns:boolean `true` if the String is `null`, empty, or all characters are `Character#isWhitespace(char)`

public static boolean isBlank(final String s)

Checks if a String is blank. A blank string is one that is either null, empty, or all characters are Character#isWhitespace(char).

Parameters

s:String: the String to check, may be null

Returns:boolean

true if the String is null, empty, or all characters are Character#isWhitespace(char)

isEmpty back to summary

isEmpty	back to summary
public static boolean isEmpty(final CharSequence cs) Checks if a CharSequence is empty ("") or null. Strings.isEmpty(null) = true Strings.isEmpty("") = true Strings.isEmpty(" ") = false Strings.isEmpty("bob") = false Strings.isEmpty(" bob ") = false Note This method changed in Lang version 2.0. It no longer trims the CharSequence. That functionality is available in isBlank(). Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isEmpty(CharSequence) Parameters cs:CharSequence the CharSequence to check, may be null Returns:boolean `true` if the CharSequence is empty or null

public static boolean isEmpty(final CharSequence cs)

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

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

Note

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

Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isEmpty(CharSequence)

Parameters

cs:CharSequence: the CharSequence to check, may be null

Returns:boolean

true if the CharSequence is empty or null

isNotBlank back to summary

isNotBlank	back to summary
public static boolean isNotBlank(final String s) Checks if a String is not blank. The opposite of `isBlank(String)`. Parameters s:String the String to check, may be `null` Returns:boolean `true` if the String is non-`null` and has content after being trimmed.

public static boolean isNotBlank(final String s)

Checks if a String is not blank. The opposite of isBlank(String).

Parameters

s:String: the String to check, may be null

Returns:boolean

true if the String is non-null and has content after being trimmed.

isNotEmpty back to summary

isNotEmpty	back to summary
public static boolean isNotEmpty(final CharSequence cs) Checks if a CharSequence is not empty ("") and not null. Strings.isNotEmpty(null) = false Strings.isNotEmpty("") = false Strings.isNotEmpty(" ") = true Strings.isNotEmpty("bob") = true Strings.isNotEmpty(" bob ") = true Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isNotEmpty(CharSequence) Parameters cs:CharSequence the CharSequence to check, may be null Returns:boolean `true` if the CharSequence is not empty and not null

public static boolean isNotEmpty(final CharSequence cs)

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

Strings.isNotEmpty(null)      = false
Strings.isNotEmpty("")        = false
Strings.isNotEmpty(" ")       = true
Strings.isNotEmpty("bob")     = true
Strings.isNotEmpty("  bob  ") = true

Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isNotEmpty(CharSequence)

Parameters

cs:CharSequence: the CharSequence to check, may be null

Returns:boolean

true if the CharSequence is not empty and not null

join back to summary

join	back to summary
public static String join(final Iterable<?> iterable, final char separator) Joins the elements of the provided `Iterable` into a single String containing the provided elements. No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings. Parameters iterable:Iterable<?> the `Iterable` providing the values to join together, may be null separator:char the separator character to use Returns:String the joined String, `null` if null iterator input

public static String join(final Iterable<?> iterable, final char separator)

Joins the elements of the provided Iterable into a single String containing the provided elements.

No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.

Parameters

iterable:Iterable<?>: the Iterable providing the values to join together, may be null
separator:char: the separator character to use

Returns:String

the joined String, null if null iterator input

join back to summary

join	back to summary
public static String join(final Iterator<?> iterator, final char separator) Joins the elements of the provided `Iterator` into a single String containing the provided elements. No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings. Parameters iterator:Iterator<?> the `Iterator` of values to join together, may be null separator:char the separator character to use Returns:String the joined String, `null` if null iterator input

public static String join(final Iterator<?> iterator, final char separator)

Joins the elements of the provided Iterator into a single String containing the provided elements.

No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.

Parameters

iterator:Iterator<?>: the Iterator of values to join together, may be null
separator:char: the separator character to use

Returns:String

the joined String, null if null iterator input

left back to summary

left	back to summary
public static String left(final String str, final int len) Gets the leftmost `len` characters of a String. If `len` characters are not available, or the String is `null`, the String will be returned without an exception. An empty String is returned if len is negative. StringUtils.left(null, ) = null StringUtils.left(, -ve) = "" StringUtils.left("", *) = "" StringUtils.left("abc", 0) = "" StringUtils.left("abc", 2) = "ab" StringUtils.left("abc", 4) = "abc" Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils. Parameters str:String the String to get the leftmost characters from, may be null len:int the length of the required String Returns:String the leftmost characters, `null` if null String input

public static String left(final String str, final int len)

Gets the leftmost len characters of a String.

If len characters are not available, or the String is null, the String will be returned without an exception. An empty String is returned if len is negative.

StringUtils.left(null, *)    = null
StringUtils.left(*, -ve)     = ""
StringUtils.left("", *)      = ""
StringUtils.left("abc", 0)   = ""
StringUtils.left("abc", 2)   = "ab"
StringUtils.left("abc", 4)   = "abc"

Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.

Parameters

str:String: the String to get the leftmost characters from, may be null
len:int: the length of the required String

Returns:String

the leftmost characters, null if null String input

quote back to summary

quote	back to summary
public static String quote(final String str) Returns a quoted string. Parameters str:String a String Returns:String `'str'`

public static String quote(final String str)

Returns a quoted string.

Parameters

str:String: a String

Returns:String

'str'

repeat back to summary

repeat	back to summary
public static String repeat(final String str, final int count) Creates a new string repeating given `str` `count` times. Parameters str:String input string count:int the repetition count Returns:String the new string Exceptions IllegalArgumentException: if either `str` is null or `count` is negative

public static String repeat(final String str, final int count)

Creates a new string repeating given str count times.

Parameters

str:String: input string
count:int: the repetition count

Returns:String

the new string

Exceptions

IllegalArgumentException:: if either str is null or count is negative

splitList	back to summary
public static String[] splitList(final String string)

toRootLowerCase back to summary

toRootLowerCase	back to summary
public static String toRootLowerCase(final String str) Shorthand for `str.toLowerCase(Locale.ROOT);` Parameters str:String The string to upper case. Returns:String a new string See Also `String#toLowerCase(Locale)`

public static String toRootLowerCase(final String str)

Shorthand for str.toLowerCase(Locale.ROOT);

Parameters

str:String: The string to upper case.

Returns:String

a new string

See Also

String#toLowerCase(Locale)

toRootUpperCase back to summary

toRootUpperCase	back to summary
public static String toRootUpperCase(final String str) Shorthand for `str.toUpperCase(Locale.ROOT);` Parameters str:String The string to lower case. Returns:String a new string See Also `String#toLowerCase(Locale)`

public static String toRootUpperCase(final String str)

Shorthand for str.toUpperCase(Locale.ROOT);

Parameters

str:String: The string to lower case.

Returns:String

a new string

See Also

String#toLowerCase(Locale)

trimToNull back to summary

trimToNull	back to summary
public static String trimToNull(final String str) Removes control characters (char <= 32) from both ends of this String returning `null` if the String is empty ("") after the trim or if it is `null`. The String is trimmed using `String#trim()`. Trim removes start and end characters <= 32. Strings.trimToNull(null) = null Strings.trimToNull("") = null Strings.trimToNull(" ") = null Strings.trimToNull("abc") = "abc" Strings.trimToNull(" abc ") = "abc" Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.trimToNull(String) Parameters str:String the String to be trimmed, may be null Returns:String the trimmed String, `null` if only chars <= 32, empty or null String input

public static String trimToNull(final String str)

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

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

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

Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.trimToNull(String)

Parameters

str:String: the String to be trimmed, may be null

Returns:String

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

public final Class Strings

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