org.apache.logging.log4j.util

Class Strings

java.lang.Object

org.apache.logging.log4j.util.Strings

public final class Strings
extends java.lang.Object

Consider this class private.

See Also:

Apache Commons Lang

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	EMPTY The empty string.
static java.lang.String	LINE_SEPARATOR OS-dependent line separator, defaults to "\n" if the system property ""line.separator" cannot be read.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Strings()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	dquote(java.lang.String str) Returns a double quoted string.
static boolean	isBlank(java.lang.String s) Checks if a String is blank.
static boolean	isEmpty(java.lang.CharSequence cs) Checks if a CharSequence is empty ("") or null.
static boolean	isNotBlank(java.lang.String s) Checks if a String is not blank.
static boolean	isNotEmpty(java.lang.CharSequence cs) Checks if a CharSequence is not empty ("") and not null.
static java.lang.String	join(java.lang.Iterable<?> iterable, char separator) Joins the elements of the provided Iterable into a single String containing the provided elements.
static java.lang.String	join(java.util.Iterator<?> iterator, char separator) Joins the elements of the provided Iterator into a single String containing the provided elements.
static java.lang.String	quote(java.lang.String str) Returns a quoted string.
java.lang.String	toRootUpperCase(java.lang.String str) Shorthand for str.toUpperCase(Locale.ROOT);
static java.lang.String	trimToNull(java.lang.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.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static final java.lang.String EMPTY

The empty string.

See Also:

Constant Field Values

LINE_SEPARATOR

public static final java.lang.String LINE_SEPARATOR

OS-dependent line separator, defaults to "\n" if the system property ""line.separator" cannot be read.

Constructor Detail

Strings

private Strings()

Method Detail

dquote

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

Returns a double quoted string.

Parameters:

str - a String

Returns:

"str"

isBlank

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

Checks if a String is blank. A blank string is one that is null, empty, or when trimmed using String.trim() is empty.

Parameters:

s - the String to check, may be null

Returns:

true if the String is null, empty, or trims to empty.

isEmpty

public static boolean isEmpty(java.lang.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 - the CharSequence to check, may be null

Returns:

true if the CharSequence is empty or null

isNotBlank

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

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

Parameters:

s - the String to check, may be null

Returns:

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

isNotEmpty

public static boolean isNotEmpty(java.lang.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 - the CharSequence to check, may be null

Returns:

true if the CharSequence is not empty and not null

quote

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

Returns a quoted string.

Parameters:

str - a String

Returns:

'str'

toRootUpperCase

public java.lang.String toRootUpperCase(java.lang.String str)

Shorthand for str.toUpperCase(Locale.ROOT);

Parameters:

str - The string to upper case.

Returns:

a new string

See Also:

String.toLowerCase(Locale)

trimToNull

public static java.lang.String trimToNull(java.lang.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 - the String to be trimmed, may be null

Returns:

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

join

public static java.lang.String join(java.lang.Iterable<?> iterable,
                                    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 - the Iterable providing the values to join together, may be null

separator - the separator character to use

Returns:

the joined String, null if null iterator input

join

public static java.lang.String join(java.util.Iterator<?> iterator,
                                    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 - the Iterator of values to join together, may be null

separator - the separator character to use

Returns:

the joined String, null if null iterator input