com.privatejgoodies.common.base

Class Strings

java.lang.Object

com.privatejgoodies.common.base.Strings

public class Strings
extends Object

Provides frequently used static null-safe String testing methods .

Author:

Karsten Lentzsch

Field Summary

Fields

Modifier and Type	Field and Description
static String	ELLIPSIS_STRING The correct ellipsis string.
static String	NO_ELLIPSIS_STRING A string with three dots that should is often meant to be the ellipsis string "…" or character '…'.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Strings()

Method Summary

Modifier and Type	Method and Description
static String	abbreviateCenter(String str, int maxLength) Abbreviates the given string if it exceeds the given maximum length by replacing its center part with an ellipsis ('…').
static boolean	isBlank(String str) Checks if the given string is whitespace, empty ("") or null.
static boolean	isEmpty(String str) Checks if the given string is empty ("") or null.
static boolean	isNotBlank(String str) Checks if the given string is not empty (""), not null and not whitespace only.
static boolean	isNotEmpty(String str) Checks if the given string is not empty ("") and not null.
static boolean	isTrimmed(String str) Checks if the given string is null, empty (""), or the first and last characters are not whitespace.
static boolean	startsWithIgnoreCase(String str, String prefix) Checks if str starts with the given prefix ignoring cases.

Methods inherited from class java.lang.Object

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

Field Detail

NO_ELLIPSIS_STRING

public static final String NO_ELLIPSIS_STRING

A string with three dots that should is often meant to be the ellipsis string "…" or character '…'.

Since:

1.7

See Also:

ELLIPSIS_STRING, Constant Field Values

ELLIPSIS_STRING

public static final String ELLIPSIS_STRING

The correct ellipsis string.

See Also:

NO_ELLIPSIS_STRING, Constant Field Values

Constructor Detail

Strings

protected Strings()

Method Detail

isBlank

public static boolean isBlank(String str)

Checks if the given string is whitespace, empty ("") or null.

 Strings.isBlank(null)    == true
 Strings.isBlank("")      == true
 Strings.isBlank(" ")     == true
 Strings.isBlank(" abc")  == false
 Strings.isBlank("abc ")  == false
 Strings.isBlank(" abc ") == false
 

Parameters:

str - the string to check, may be null

Returns:

true if the string is whitespace, empty or null

See Also:

isEmpty(String)

isNotBlank

public static boolean isNotBlank(String str)

Checks if the given string is not empty (""), not null and not whitespace only.

 Strings.isNotBlank(null)    == false
 Strings.isNotBlank("")      == false
 Strings.isNotBlank(" ")     == false
 Strings.isNotBlank(" abc")  == true
 Strings.isNotBlank("abc ")  == true
 Strings.isNotBlank(" abc ") == true
 

Parameters:

str - the string to check, may be null

Returns:

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

See Also:

isEmpty(String)

isEmpty

public static boolean isEmpty(String str)

Checks if the given string is empty ("") or null.

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

Parameters:

str - the string to check, may be null

Returns:

true if the string is empty or null

See Also:

isBlank(String)

isNotEmpty

public static boolean isNotEmpty(String str)

Checks if the given string is not empty ("") and not null.

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

Parameters:

str - the string to check, may be null

Returns:

true if the string is not empty and not null

See Also:

isBlank(String)

isTrimmed

public static boolean isTrimmed(String str)

Checks if the given string is null, empty (""), or the first and last characters are not whitespace.

 Strings.isTrimmed(null)  == true
 Strings.isTrimmed("")    == true
 Strings.isTrimmed(" ")   == false
 Strings.isTrimmed("Hi")  == true
 Strings.isTrimmed("Hi ") == false
 Strings.isTrimmed(" Hi") == false
 

Parameters:

str - the string to check, may be null

Returns:

true if the string is null, empty, or the first and last characters are not whitespace.

Since:

1.3

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(String str,
                                           String prefix)

Checks if str starts with the given prefix ignoring cases. null is handled safely; if both arguments are null, true is returned, false otherwise.

 Strings.startsWithIgnoreCase(null, null)      == true
 Strings.startsWithIgnoreCase("a", null)       == false
 Strings.startsWithIgnoreCase(null, "a")       == false
 Strings.startsWithIgnoreCase("",  "")         == true
 Strings.startsWithIgnoreCase(" ", "")         == true
 Strings.startsWithIgnoreCase("John", "J")     == true
 Strings.startsWithIgnoreCase("John", "Jo")    == true
 Strings.startsWithIgnoreCase("John", "Joh")   == true
 Strings.startsWithIgnoreCase("John", "joh")   == true
 Strings.startsWithIgnoreCase("john", "Joh")   == true
 Strings.startsWithIgnoreCase("john", "joh")   == true
 Strings.startsWithIgnoreCase("John", "John")  == true
 Strings.startsWithIgnoreCase("John", "john")  == true
 Strings.startsWithIgnoreCase("John", "Jonny") == false
 

Parameters:

str - the test string to check, may be null

prefix - the prefix to check for, may be null

Returns:

true, if the string starts with the prefix, ignoring cases, false otherwise

See Also:

String.startsWith(java.lang.String)

abbreviateCenter

public static String abbreviateCenter(String str,
                                      int maxLength)

Abbreviates the given string if it exceeds the given maximum length by replacing its center part with an ellipsis ('…'). If the string is null or shorter than the limit, it is returned as is.

 Strings.abbreviateCenter(null,      3) == null
 Strings.abbreviateCenter("",        3) == ""
 Strings.abbreviateCenter(" ",       3) == " "
 Strings.abbreviateCenter("a",       3) == "a"
 Strings.abbreviateCenter("ab",      3) == "ab"
 Strings.abbreviateCenter("abc",     3) == "abc"
 Strings.abbreviateCenter("abcd",    3) == "a…d"
 Strings.abbreviateCenter("abcde",   3) == "a…e"
 Strings.abbreviateCenter("abcde",   4) == "ab…e"
 Strings.abbreviateCenter("abcdef",  4) == "ab…f"
 Strings.abbreviateCenter("abcdefg", 5) == "ab…fg"
 

Parameters:

str - the source string

maxLength - the maximum length of the result string

Returns:

str if its length is less than or equal to maxLength, an abbreviated string with length maxLength where the center is replaced by an ellipsis