Package org.apache.commons.lang3

Class CharUtils

java.lang.Object
org.apache.commons.lang3.CharUtils
public class CharUtils extends Object
Operations on char primitives and Character objects.

This class tries to handle null input gracefully. An exception will not be thrown for a null input. Each method documents its behavior in more detail.

#ThreadSafe#

Since:
2.1

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final char
    CR
    Carriage return character CR ('\r', Unicode 000d).
    static final char
    LF
    Linefeed character LF ('\n', Unicode 000a).
    static final char
    NUL
    null control character ('\0'), abbreviated NUL.

  • Constructor Summary

    Constructors
    Constructor
    Description
    CharUtils()
    Deprecated.
    TODO Make private in 4.0.

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    compare(char x, char y)
    Compares two char values numerically.
    static boolean
    isAscii(char ch)
    Checks whether the character is ASCII 7 bit.
    static boolean
    isAsciiAlpha(char ch)
    Checks whether the character is ASCII 7 bit alphabetic.
    static boolean
    isAsciiAlphaLower(char ch)
    Checks whether the character is ASCII 7 bit alphabetic lower case.
    static boolean
    isAsciiAlphanumeric(char ch)
    Checks whether the character is ASCII 7 bit numeric.
    static boolean
    isAsciiAlphaUpper(char ch)
    Checks whether the character is ASCII 7 bit alphabetic upper case.
    static boolean
    isAsciiControl(char ch)
    Checks whether the character is ASCII 7 bit control.
    static boolean
    isAsciiNumeric(char ch)
    Checks whether the character is ASCII 7 bit numeric.
    static boolean
    isAsciiPrintable(char ch)
    Checks whether the character is ASCII 7 bit printable.
    static char
    toChar(Character ch)
    Converts the Character to a char throwing an exception for null.
    static char
    toChar(Character ch, char defaultValue)
    Converts the Character to a char handling null.
    static char
    toChar(String str)
    Converts the String to a char using the first character, throwing an exception on empty Strings.
    static char
    toChar(String str, char defaultValue)
    Converts the String to a char using the first character, defaulting the value on empty Strings.
    static Character
    toCharacterObject(char c)
    Deprecated.
    Use Character.valueOf(char).
    static Character
    toCharacterObject(String str)
    Converts the String to a Character using the first character, returning null for empty Strings.
    static int
    toIntValue(char ch)
    Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
    static int
    toIntValue(char ch, int defaultValue)
    Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
    static int
    toIntValue(Character ch)
    Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
    static int
    toIntValue(Character ch, int defaultValue)
    Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
    static String
    toString(char ch)
    Converts the character to a String that contains the one character.
    static String
    toString(Character ch)
    Converts the character to a String that contains the one character.
    static String
    unicodeEscaped(char ch)
    Converts the string to the Unicode format ' '.
    static String
    unicodeEscaped(Character ch)
    Converts the string to the Unicode format ' '.

    Methods inherited from class java.lang.Object

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

  • Field Details

  • Constructor Details

    • CharUtils

      @Deprecated public CharUtils()
      Deprecated.
      TODO Make private in 4.0.
      CharUtils instances should NOT be constructed in standard programming. Instead, the class should be used as CharUtils.toString('c');.

      This constructor is public to permit tools that require a JavaBean instance to operate.

  • Method Details

    • compare

      public static int compare(char x, char y)
      Compares two char values numerically. This is the same functionality as provided in Java 7.
      Parameters:
      x - the first char to compare
      y - the second char to compare
      Returns:
      the value 0 if x == y; a value less than 0 if x < y; and a value greater than 0 if x > y
      Since:
      3.4

    • isAscii

      public static boolean isAscii(char ch)
      Checks whether the character is ASCII 7 bit. 
         CharUtils.isAscii('a')  = true
   CharUtils.isAscii('A')  = true
   CharUtils.isAscii('3')  = true
   CharUtils.isAscii('-')  = true
   CharUtils.isAscii('\n') = true
   CharUtils.isAscii('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if less than 128

    • isAsciiAlpha

      public static boolean isAsciiAlpha(char ch)
      Checks whether the character is ASCII 7 bit alphabetic. 
         CharUtils.isAsciiAlpha('a')  = true
   CharUtils.isAsciiAlpha('A')  = true
   CharUtils.isAsciiAlpha('3')  = false
   CharUtils.isAsciiAlpha('-')  = false
   CharUtils.isAsciiAlpha('\n') = false
   CharUtils.isAsciiAlpha('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if between 65 and 90 or 97 and 122 inclusive

    • isAsciiAlphaLower

      public static boolean isAsciiAlphaLower(char ch)
      Checks whether the character is ASCII 7 bit alphabetic lower case. 
         CharUtils.isAsciiAlphaLower('a')  = true
   CharUtils.isAsciiAlphaLower('A')  = false
   CharUtils.isAsciiAlphaLower('3')  = false
   CharUtils.isAsciiAlphaLower('-')  = false
   CharUtils.isAsciiAlphaLower('\n') = false
   CharUtils.isAsciiAlphaLower('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if between 97 and 122 inclusive

    • isAsciiAlphanumeric

      public static boolean isAsciiAlphanumeric(char ch)
      Checks whether the character is ASCII 7 bit numeric. 
         CharUtils.isAsciiAlphanumeric('a')  = true
   CharUtils.isAsciiAlphanumeric('A')  = true
   CharUtils.isAsciiAlphanumeric('3')  = true
   CharUtils.isAsciiAlphanumeric('-')  = false
   CharUtils.isAsciiAlphanumeric('\n') = false
   CharUtils.isAsciiAlphanumeric('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if between 48 and 57 or 65 and 90 or 97 and 122 inclusive

    • isAsciiAlphaUpper

      public static boolean isAsciiAlphaUpper(char ch)
      Checks whether the character is ASCII 7 bit alphabetic upper case. 
         CharUtils.isAsciiAlphaUpper('a')  = false
   CharUtils.isAsciiAlphaUpper('A')  = true
   CharUtils.isAsciiAlphaUpper('3')  = false
   CharUtils.isAsciiAlphaUpper('-')  = false
   CharUtils.isAsciiAlphaUpper('\n') = false
   CharUtils.isAsciiAlphaUpper('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if between 65 and 90 inclusive

    • isAsciiControl

      public static boolean isAsciiControl(char ch)
      Checks whether the character is ASCII 7 bit control. 
         CharUtils.isAsciiControl('a')  = false
   CharUtils.isAsciiControl('A')  = false
   CharUtils.isAsciiControl('3')  = false
   CharUtils.isAsciiControl('-')  = false
   CharUtils.isAsciiControl('\n') = true
   CharUtils.isAsciiControl('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if less than 32 or equals 127

    • isAsciiNumeric

      public static boolean isAsciiNumeric(char ch)
      Checks whether the character is ASCII 7 bit numeric. 
         CharUtils.isAsciiNumeric('a')  = false
   CharUtils.isAsciiNumeric('A')  = false
   CharUtils.isAsciiNumeric('3')  = true
   CharUtils.isAsciiNumeric('-')  = false
   CharUtils.isAsciiNumeric('\n') = false
   CharUtils.isAsciiNumeric('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if between 48 and 57 inclusive

    • isAsciiPrintable

      public static boolean isAsciiPrintable(char ch)
      Checks whether the character is ASCII 7 bit printable. 
         CharUtils.isAsciiPrintable('a')  = true
   CharUtils.isAsciiPrintable('A')  = true
   CharUtils.isAsciiPrintable('3')  = true
   CharUtils.isAsciiPrintable('-')  = true
   CharUtils.isAsciiPrintable('\n') = false
   CharUtils.isAsciiPrintable('©') = false
      Parameters:
      ch - the character to check
      Returns:
      true if between 32 and 126 inclusive

    • toChar

      public static char toChar(Character ch)
      Converts the Character to a char throwing an exception for null. 
         CharUtils.toChar(' ')  = ' '
   CharUtils.toChar('A')  = 'A'
   CharUtils.toChar(null) throws IllegalArgumentException
      Parameters:
      ch - the character to convert
      Returns:
      the char value of the Character
      Throws:
      NullPointerException - if the Character is null

    • toChar

      public static char toChar(Character ch, char defaultValue)
      Converts the Character to a char handling null. 
         CharUtils.toChar(null, 'X') = 'X'
   CharUtils.toChar(' ', 'X')  = ' '
   CharUtils.toChar('A', 'X')  = 'A'
      Parameters:
      ch - the character to convert
      defaultValue - the value to use if the Character is null
      Returns:
      the char value of the Character or the default if null

    • toChar

      public static char toChar(String str)
      Converts the String to a char using the first character, throwing an exception on empty Strings. 
         CharUtils.toChar("A")  = 'A'
   CharUtils.toChar("BA") = 'B'
   CharUtils.toChar(null) throws IllegalArgumentException
   CharUtils.toChar("")   throws IllegalArgumentException
      Parameters:
      str - the character to convert
      Returns:
      the char value of the first letter of the String
      Throws:
      NullPointerException - if the string is null
      IllegalArgumentException - if the String is empty

    • toChar

      public static char toChar(String str, char defaultValue)
      Converts the String to a char using the first character, defaulting the value on empty Strings. 
         CharUtils.toChar(null, 'X') = 'X'
   CharUtils.toChar("", 'X')   = 'X'
   CharUtils.toChar("A", 'X')  = 'A'
   CharUtils.toChar("BA", 'X') = 'B'
      Parameters:
      str - the character to convert
      defaultValue - the value to use if the Character is null
      Returns:
      the char value of the first letter of the String or the default if null

    • toCharacterObject

      @Deprecated public static Character toCharacterObject(char c)
      Deprecated.
      Use Character.valueOf(char).
      Delegates to Character.valueOf(char).
      Parameters:
      c - the character to convert
      Returns:
      a Character representing c.

    • toCharacterObject

      public static Character toCharacterObject(String str)
      Converts the String to a Character using the first character, returning null for empty Strings.

      For ASCII 7 bit characters, this uses a cache that will return the same Character object each time.

         CharUtils.toCharacterObject(null) = null
   CharUtils.toCharacterObject("")   = null
   CharUtils.toCharacterObject("A")  = 'A'
   CharUtils.toCharacterObject("BA") = 'B'
      Parameters:
      str - the character to convert
      Returns:
      the Character value of the first letter of the String

    • toIntValue

      public static int toIntValue(char ch)
      Converts the character to the Integer it represents, throwing an exception if the character is not numeric.

      This method converts the char '1' to the int 1 and so on.

         CharUtils.toIntValue('3')  = 3
   CharUtils.toIntValue('A')  throws IllegalArgumentException
      Parameters:
      ch - the character to convert
      Returns:
      the int value of the character
      Throws:
      IllegalArgumentException - if the character is not ASCII numeric

    • toIntValue

      public static int toIntValue(char ch, int defaultValue)
      Converts the character to the Integer it represents, throwing an exception if the character is not numeric.

      This method converts the char '1' to the int 1 and so on.

         CharUtils.toIntValue('3', -1)  = 3
   CharUtils.toIntValue('A', -1)  = -1
      Parameters:
      ch - the character to convert
      defaultValue - the default value to use if the character is not numeric
      Returns:
      the int value of the character

    • toIntValue

      public static int toIntValue(Character ch)
      Converts the character to the Integer it represents, throwing an exception if the character is not numeric.

      This method converts the char '1' to the int 1 and so on.

         CharUtils.toIntValue('3')  = 3
   CharUtils.toIntValue(null) throws IllegalArgumentException
   CharUtils.toIntValue('A')  throws IllegalArgumentException
      Parameters:
      ch - the character to convert, not null
      Returns:
      the int value of the character
      Throws:
      NullPointerException - if the Character is null
      IllegalArgumentException - if the Character is not ASCII numeric

    • toIntValue

      public static int toIntValue(Character ch, int defaultValue)
      Converts the character to the Integer it represents, throwing an exception if the character is not numeric.

      This method converts the char '1' to the int 1 and so on.

         CharUtils.toIntValue(null, -1) = -1
   CharUtils.toIntValue('3', -1)  = 3
   CharUtils.toIntValue('A', -1)  = -1
      Parameters:
      ch - the character to convert
      defaultValue - the default value to use if the character is not numeric
      Returns:
      the int value of the character

    • toString

      public static String toString(char ch)
      Converts the character to a String that contains the one character.

      For ASCII 7 bit characters, this uses a cache that will return the same String object each time.

         CharUtils.toString(' ')  = " "
   CharUtils.toString('A')  = "A"
      Parameters:
      ch - the character to convert
      Returns:
      a String containing the one specified character

    • toString

      public static String toString(Character ch)
      Converts the character to a String that contains the one character.

      For ASCII 7 bit characters, this uses a cache that will return the same String object each time.

      If null is passed in, null will be returned.

         CharUtils.toString(null) = null
   CharUtils.toString(' ')  = " "
   CharUtils.toString('A')  = "A"
      Parameters:
      ch - the character to convert
      Returns:
      a String containing the one specified character

    • unicodeEscaped

      public static String unicodeEscaped(char ch)
      Converts the string to the Unicode format ' '.

      This format is the Java source code format.

         CharUtils.unicodeEscaped(' ') = " "
   CharUtils.unicodeEscaped('A') = "A"
      Parameters:
      ch - the character to convert
      Returns:
      the escaped Unicode string

    • unicodeEscaped

      public static String unicodeEscaped(Character ch)
      Converts the string to the Unicode format ' '.

      This format is the Java source code format.

      If null is passed in, null will be returned.

         CharUtils.unicodeEscaped(null) = null
   CharUtils.unicodeEscaped(' ')  = " "
   CharUtils.unicodeEscaped('A')  = "A"
      Parameters:
      ch - the character to convert, may be null
      Returns:
      the escaped Unicode string, null if null input