Package com.shaiksphere.mindsmine.jems

Class StringHelper

java.lang.Object

com.shaiksphere.mindsmine.jems.StringHelper

public final class StringHelper
extends Object

A collection of useful static methods to deal with strings.

Since:

1.0

Author:

Mohammed Shaik Hussain Ali

See Also:

String

Method Summary

Modifier and Type	Method	Description
static boolean	areEqual(String string1, String string2)	Returns true if the passed values are equal, ignoring the case, false otherwise.
static boolean	areEqual(String string1, String string2, boolean lenient)	Returns true if the passed values are equal, false otherwise.
static String	getNullSafe(String string)	Returns a non-null string, even if the object being passed is a null string.
static boolean	isBlank(String string)	Returns true if the passed value is an empty string, false otherwise.
static boolean	isOnlyDigits(String string)	Returns true if the passed string contains only digits, false otherwise.
static boolean	isPalindrome(String string)	Returns true if the passed string is a palindrome, ignoring the case, false otherwise.
static boolean	isPalindrome(String string, boolean lenient)	Returns true if the passed string is a palindrome, false otherwise.

Methods inherited from class java.lang.Object

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

Method Details

getNullSafe

public static String getNullSafe(String string)

Returns a non-null string, even if the object being passed is a null string.

If the passed-in object is a non-null string, then it is returned as-is.

Example usage:

      String str1 = "Hello";
      String str2 = null;

      String str3 = StringHelper.getNullSafe(str1);

      String str4 = StringHelper.getNullSafe(str2);

      // str3 now contains the string: "Hello"
      // str4 now contains the string: ""
 

Parameters:

string - The string to safeguard against null.

Returns:

If str is null then "" (empty string).

Since:

1.0

isBlank

public static boolean isBlank(String string)

Returns true if the passed value is an empty string, false otherwise.

The value is deemed to be an empty string if it is either:

• null
• a zero-length string
• comprised of whitespaces as defined by Character.isWhitespace(char)

Example usage:

     StringHelper.isBlank(null)          = true
     StringHelper.isBlank("")            = true
     StringHelper.isBlank(" ")           = true
     StringHelper.isBlank("something ")  = false
 

Parameters:

string - The value to test.

Returns:

true if the passed value is an empty string, false otherwise.

Since:

1.0

areEqual

public static boolean areEqual(String string1, String string2)

Returns true if the passed values are equal, ignoring the case, false otherwise.

Convenience method equivalent to StringHelper.areEqual(string1, string2, true)

Parameters:

string1 - to compare

string2 - to compare

Returns:

whether two strings are equal

Since:

1.0

See Also:

areEqual(String, String, boolean)

areEqual

public static boolean areEqual(String string1, String string2, boolean lenient)

Returns true if the passed values are equal, false otherwise.

• When the lenient flag is set to true, the comparison will ignore the case and trim the strings before comparing; the two strings are considered equal if,
  • Both strings are blank, as defined by isBlank(String).
  • Trimmed versions of both strings, as defined by String.trim(), are equal.
• When the lenient flag is set to false, the two strings are considered equal if,
  • Both strings are not null
  • Both strings represent the same sequence of characters

Example usage:

     StringHelper.areEqual(null, null, true)       = true
     StringHelper.areEqual(null, "", true)         = true
     StringHelper.areEqual("", null, true)         = true
     StringHelper.areEqual("", "", true)           = true
     StringHelper.areEqual("   ", "", true)        = true
     StringHelper.areEqual(" abc", "abc ", true)   = true
     StringHelper.areEqual("", "abc", true)        = false
     StringHelper.areEqual("ab c", "abc", true)    = false
     StringHelper.areEqual("ABC", "abc", true)     = true
     StringHelper.areEqual("abc", "abc", true)     = true

     StringHelper.areEqual(null, null, false)      = false
     StringHelper.areEqual(null, "", false)        = false
     StringHelper.areEqual("", null, false)        = false
     StringHelper.areEqual("", "", false)          = true
     StringHelper.areEqual("   ", "", false)       = false
     StringHelper.areEqual(" abc", "abc ", false)  = false
     StringHelper.areEqual("", "abc", false)       = false
     StringHelper.areEqual("ab c", "abc", false)   = false
     StringHelper.areEqual("ABC", "abc", false)    = false
     StringHelper.areEqual("abc", "abc", false)    = true
 

Parameters:

string1 - to compare

string2 - to compare

lenient - whether to be lenient or not

Returns:

whether two strings are equal

Since:

2.1.0

See Also:

String.equalsIgnoreCase(String), String.equals(Object)

isOnlyDigits

public static boolean isOnlyDigits(String string)

Returns true if the passed string contains only digits, false otherwise.

Example usage:

     StringHelper.isOnlyDigits(null)          = false
     StringHelper.isOnlyDigits("")            = false
     StringHelper.isOnlyDigits(" ")           = false
     StringHelper.isOnlyDigits("something ")  = false
     StringHelper.isOnlyDigits("11.67")       = false
     StringHelper.isOnlyDigits("17650")       = true
 

Parameters:

string - to check

Returns:

whether the string contains only digits

Since:

1.0

See Also:

String.matches(String)

isPalindrome

public static boolean isPalindrome(String string)

Returns true if the passed string is a palindrome, ignoring the case, false otherwise.

Convenience method equivalent to StringHelper.isPalindrome(string, true)

Parameters:

string - to check

Returns:

if the string is a Palindrome

Since:

2.1.0

See Also:

isPalindrome(String, boolean)

isPalindrome

public static boolean isPalindrome(String string, boolean lenient)

Returns true if the passed string is a palindrome, false otherwise.

A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward or forward, such as madam or kayak.

Convenience method equivalent to StringHelper.areEqual(string, string.reverse, flag)

Example usage:

     StringHelper.isPalindrome(null, true)      = true
     StringHelper.isPalindrome("", true)        = true
     StringHelper.isPalindrome("   ", true)     = true
     StringHelper.isPalindrome(" aba", true)    = true
     StringHelper.isPalindrome("aba", true)     = true
     StringHelper.isPalindrome("mAdAm", true)   = true
     StringHelper.isPalindrome("madAm", true)   = true
     StringHelper.isPalindrome("madam", true)   = true
     StringHelper.isPalindrome("Madam", true)   = true
     StringHelper.isPalindrome("hello", true)   = false

     StringHelper.isPalindrome(null, false)     = false
     StringHelper.isPalindrome("", false)       = true
     StringHelper.isPalindrome("   ", false)    = true
     StringHelper.isPalindrome(" aba", false)   = false
     StringHelper.isPalindrome("aba", false)    = true
     StringHelper.isPalindrome("mAdAm", false)  = true
     StringHelper.isPalindrome("madAm", false)  = false
     StringHelper.isPalindrome("madam", false)  = true
     StringHelper.isPalindrome("Madam", false)  = false
     StringHelper.isPalindrome("hello", false)  = false
 

Parameters:

string - to check

lenient - whether to be lenient or not

Returns:

if the string is a Palindrome

Since:

2.1.0

See Also:

areEqual(String, String, boolean), Palindrome (Wikipedia)