Class CharUtils
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 behaviour in more detail.
#ThreadSafe#
- Since:
- 2.1
- Version:
- $Id: CharUtils.java 1056988 2011-01-09 17:58:53Z niallp $
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionCharUtils
instances should NOT be constructed in standard programming. -
Method Summary
Modifier and TypeMethodDescriptionstatic 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
Converts the Character to a char throwing an exception fornull
.static char
Converts the Character to a char handlingnull
.static char
Converts the String to a char using the first character, throwing an exception on empty Strings.static char
Converts the String to a char using the first character, defaulting the value on empty Strings.static Character
toCharacterObject
(char ch) Converts the character to a Character.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
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
Converts the string to the unicode format ' '.
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Field Details
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LF
public static final char LF- Since:
- 2.2
- See Also:
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CR
public static final char CR- Since:
- 2.2
- See Also:
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Constructor Details
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CharUtils
public CharUtils()CharUtils
instances should NOT be constructed in standard programming. Instead, the class should be used asCharUtils.toString('c');
.This constructor is public to permit tools that require a JavaBean instance to operate.
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Method Details
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toCharacterObject
Converts the character to a Character.
For ASCII 7 bit characters, this uses a cache that will return the same Character object each time.
CharUtils.toCharacterObject(' ') = ' ' CharUtils.toCharacterObject('A') = 'A'
- Parameters:
ch
- the character to convert- Returns:
- a Character of the specified character
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toCharacterObject
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
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toChar
Converts the Character to a char throwing an exception for
null
.CharUtils.toChar(null) = IllegalArgumentException CharUtils.toChar(' ') = ' ' CharUtils.toChar('A') = 'A'
- Parameters:
ch
- the character to convert- Returns:
- the char value of the Character
- Throws:
IllegalArgumentException
- if the Character is null
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toChar
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 convertdefaultValue
- the value to use if the Character is null- Returns:
- the char value of the Character or the default if null
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toChar
Converts the String to a char using the first character, throwing an exception on empty Strings.
CharUtils.toChar(null) = IllegalArgumentException CharUtils.toChar("") = IllegalArgumentException CharUtils.toChar("A") = 'A' CharUtils.toChar("BA") = 'B'
- Parameters:
str
- the character to convert- Returns:
- the char value of the first letter of the String
- Throws:
IllegalArgumentException
- if the String is empty
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toChar
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 convertdefaultValue
- 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
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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 coverts the char '1' to the int 1 and so on.
CharUtils.toIntValue('3') = 3 CharUtils.toIntValue('A') = IllegalArgumentException
- Parameters:
ch
- the character to convert- Returns:
- the int value of the character
- Throws:
IllegalArgumentException
- if the character is not ASCII numeric
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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 coverts 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 convertdefaultValue
- the default value to use if the character is not numeric- Returns:
- the int value of the character
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toIntValue
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
This method coverts the char '1' to the int 1 and so on.
CharUtils.toIntValue(null) = IllegalArgumentException CharUtils.toIntValue('3') = 3 CharUtils.toIntValue('A') = IllegalArgumentException
- Parameters:
ch
- the character to convert, not null- Returns:
- the int value of the character
- Throws:
IllegalArgumentException
- if the Character is not ASCII numeric or is null
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toIntValue
Converts the character to the Integer it represents, throwing an exception if the character is not numeric.
This method coverts 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 convertdefaultValue
- the default value to use if the character is not numeric- Returns:
- the int value of the character
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toString
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
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toString
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
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unicodeEscaped
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
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unicodeEscaped
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
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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
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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
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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
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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
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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
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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
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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
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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
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