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 behaviour in more detail.
#ThreadSafe#
Modifier and Type | Field and Description |
---|---|
static char |
CR
carriage return CR ('\r'). |
static char |
LF
linefeed LF ('\n'). |
Constructor and Description |
---|
CharUtils()
CharUtils instances should NOT be constructed in standard programming. |
Modifier and Type | Method and Description |
---|---|
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 ch)
Deprecated.
Java 5 introduced
Character.valueOf(char) which caches chars 0 through 127. |
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(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 int |
toIntValue(char 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 ' '.
|
public static final char LF
linefeed LF ('\n').public static final char CR
carriage return CR ('\r').public CharUtils()
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.
@Deprecated public static Character toCharacterObject(char ch)
Character.valueOf(char)
which caches chars 0 through 127.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'
ch
- the character to convertpublic 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'
str
- the character to convertpublic 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
ch
- the character to convertIllegalArgumentException
- if the Character is nullpublic 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'
ch
- the character to convertdefaultValue
- the value to use if the Character is nullpublic 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
str
- the character to convertIllegalArgumentException
- if the String is emptypublic 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'
str
- the character to convertdefaultValue
- the value to use if the Character is nullpublic 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') throws IllegalArgumentException
ch
- the character to convertIllegalArgumentException
- if the character is not ASCII numericpublic 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
ch
- the character to convertdefaultValue
- the default value to use if the character is not numericpublic static int toIntValue(Character 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(null) throws IllegalArgumentException CharUtils.toIntValue('A') throws IllegalArgumentException
ch
- the character to convert, not nullIllegalArgumentException
- if the Character is not ASCII numeric or is nullpublic 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 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
ch
- the character to convertdefaultValue
- the default value to use if the character is not numericpublic 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"
ch
- the character to convertpublic 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"
ch
- the character to convertpublic 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"
ch
- the character to convertpublic 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"
ch
- the character to convert, may be nullpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkpublic 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
ch
- the character to checkCopyright © 2001–2014 The Apache Software Foundation. All rights reserved.