com.jgoodies.common.base
Class Strings

java.lang.Object
  extended by com.jgoodies.common.base.Strings

public class Strings
extends Object

Provides frequently used static null-safe String testing methods .

Version:
$Revision: 1.7 $
Author:
Karsten Lentzsch

Constructor Summary
protected Strings()
           
 
Method Summary
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
 

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


Copyright © 2009-2012 JGoodies Karsten Lentzsch. All Rights Reserved.