public final class Character extends Object implements Serializable, Comparable<Character>
Character class wraps a value of the primitive
type char in an object. An object of type
Character contains a single field whose type is
char.
In addition, this class provides several methods for determining a character's category (lowercase letter, digit, etc.) and for converting characters from uppercase to lowercase and vice versa.
Character information is based on the Unicode Standard, version 6.2.0.
The methods and data of class Character are defined by
the information in the UnicodeData file that is part of the
Unicode Character Database maintained by the Unicode
Consortium. This file specifies various properties including name
and general category for every defined Unicode code point or
character range.
The file and its description are available from the Unicode Consortium at:
The char data type (and therefore the value that a
Character object encapsulates) are based on the
original Unicode specification, which defined characters as
fixed-width 16-bit entities. The Unicode Standard has since been
changed to allow for characters whose representation requires more
than 16 bits. The range of legal code points is now
U+0000 to U+10FFFF, known as Unicode scalar value.
(Refer to the
definition of the U+n notation in the Unicode
Standard.)
The set of characters from U+0000 to U+FFFF is
sometimes referred to as the Basic Multilingual Plane (BMP).
Characters whose code points are greater
than U+FFFF are called supplementary characters. The Java
platform uses the UTF-16 representation in char arrays and
in the String and StringBuffer classes. In
this representation, supplementary characters are represented as a pair
of char values, the first from the high-surrogates
range, (\uD800-\uDBFF), the second from the
low-surrogates range (\uDC00-\uDFFF).
A char value, therefore, represents Basic
Multilingual Plane (BMP) code points, including the surrogate
code points, or code units of the UTF-16 encoding. An
int value represents all Unicode code points,
including supplementary code points. The lower (least significant)
21 bits of int are used to represent Unicode code
points and the upper (most significant) 11 bits must be zero.
Unless otherwise specified, the behavior with respect to
supplementary characters and surrogate char values is
as follows:
char value cannot support
supplementary characters. They treat char values from the
surrogate ranges as undefined characters. For example,
Character.isLetter('\uD840') returns false, even though
this specific value if followed by any low-surrogate value in a string
would represent a letter.
int value support all
Unicode characters, including supplementary characters. For
example, Character.isLetter(0x2F81A) returns
true because the code point value represents a letter
(a CJK ideograph).
In the Java SE API documentation, Unicode code point is
used for character values in the range between U+0000 and U+10FFFF,
and Unicode code unit is used for 16-bit
char values that are code units of the UTF-16
encoding. For more information on Unicode terminology, refer to the
Unicode Glossary.
| Modifier and Type | Class and Description |
|---|---|
static class |
Character.Subset
Instances of this class represent particular subsets of the Unicode
character set.
|
static class |
Character.UnicodeBlock
A family of character subsets representing the character blocks in the
Unicode specification.
|
static class |
Character.UnicodeScript
A family of character subsets representing the character scripts
defined in the
Unicode Standard Annex #24: Script Names.
|
| Modifier and Type | Field and Description |
|---|---|
static int |
BYTES
The number of bytes used to represent a
char value in unsigned
binary form. |
static byte |
COMBINING_SPACING_MARK
General category "Mc" in the Unicode specification.
|
static byte |
CONNECTOR_PUNCTUATION
General category "Pc" in the Unicode specification.
|
static byte |
CONTROL
General category "Cc" in the Unicode specification.
|
static byte |
CURRENCY_SYMBOL
General category "Sc" in the Unicode specification.
|
static byte |
DASH_PUNCTUATION
General category "Pd" in the Unicode specification.
|
static byte |
DECIMAL_DIGIT_NUMBER
General category "Nd" in the Unicode specification.
|
static byte |
DIRECTIONALITY_ARABIC_NUMBER
Weak bidirectional character type "AN" in the Unicode specification.
|
static byte |
DIRECTIONALITY_BOUNDARY_NEUTRAL
Weak bidirectional character type "BN" in the Unicode specification.
|
static byte |
DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
Weak bidirectional character type "CS" in the Unicode specification.
|
static byte |
DIRECTIONALITY_EUROPEAN_NUMBER
Weak bidirectional character type "EN" in the Unicode specification.
|
static byte |
DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
Weak bidirectional character type "ES" in the Unicode specification.
|
static byte |
DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
Weak bidirectional character type "ET" in the Unicode specification.
|
static byte |
DIRECTIONALITY_LEFT_TO_RIGHT
Strong bidirectional character type "L" in the Unicode specification.
|
static byte |
DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING
Strong bidirectional character type "LRE" in the Unicode specification.
|
static byte |
DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE
Strong bidirectional character type "LRO" in the Unicode specification.
|
static byte |
DIRECTIONALITY_NONSPACING_MARK
Weak bidirectional character type "NSM" in the Unicode specification.
|
static byte |
DIRECTIONALITY_OTHER_NEUTRALS
Neutral bidirectional character type "ON" in the Unicode specification.
|
static byte |
DIRECTIONALITY_PARAGRAPH_SEPARATOR
Neutral bidirectional character type "B" in the Unicode specification.
|
static byte |
DIRECTIONALITY_POP_DIRECTIONAL_FORMAT
Weak bidirectional character type "PDF" in the Unicode specification.
|
static byte |
DIRECTIONALITY_RIGHT_TO_LEFT
Strong bidirectional character type "R" in the Unicode specification.
|
static byte |
DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC
Strong bidirectional character type "AL" in the Unicode specification.
|
static byte |
DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING
Strong bidirectional character type "RLE" in the Unicode specification.
|
static byte |
DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE
Strong bidirectional character type "RLO" in the Unicode specification.
|
static byte |
DIRECTIONALITY_SEGMENT_SEPARATOR
Neutral bidirectional character type "S" in the Unicode specification.
|
static byte |
DIRECTIONALITY_UNDEFINED
Undefined bidirectional character type.
|
static byte |
DIRECTIONALITY_WHITESPACE
Neutral bidirectional character type "WS" in the Unicode specification.
|
static byte |
ENCLOSING_MARK
General category "Me" in the Unicode specification.
|
static byte |
END_PUNCTUATION
General category "Pe" in the Unicode specification.
|
static byte |
FINAL_QUOTE_PUNCTUATION
General category "Pf" in the Unicode specification.
|
static byte |
FORMAT
General category "Cf" in the Unicode specification.
|
static byte |
INITIAL_QUOTE_PUNCTUATION
General category "Pi" in the Unicode specification.
|
static byte |
LETTER_NUMBER
General category "Nl" in the Unicode specification.
|
static byte |
LINE_SEPARATOR
General category "Zl" in the Unicode specification.
|
static byte |
LOWERCASE_LETTER
General category "Ll" in the Unicode specification.
|
static byte |
MATH_SYMBOL
General category "Sm" in the Unicode specification.
|
static int |
MAX_CODE_POINT
The maximum value of a
Unicode code point, constant
U+10FFFF. |
static char |
MAX_HIGH_SURROGATE
The maximum value of a
Unicode high-surrogate code unit
in the UTF-16 encoding, constant
'\uDBFF'. |
static char |
MAX_LOW_SURROGATE
The maximum value of a
Unicode low-surrogate code unit
in the UTF-16 encoding, constant
'\uDFFF'. |
static int |
MAX_RADIX
The maximum radix available for conversion to and from strings.
|
static char |
MAX_SURROGATE
The maximum value of a Unicode surrogate code unit in the
UTF-16 encoding, constant
'\uDFFF'. |
static char |
MAX_VALUE
The constant value of this field is the largest value of type
char, '\uFFFF'. |
static int |
MIN_CODE_POINT
The minimum value of a
Unicode code point, constant
U+0000. |
static char |
MIN_HIGH_SURROGATE
The minimum value of a
Unicode high-surrogate code unit
in the UTF-16 encoding, constant
'\uD800'. |
static char |
MIN_LOW_SURROGATE
The minimum value of a
Unicode low-surrogate code unit
in the UTF-16 encoding, constant
'\uDC00'. |
static int |
MIN_RADIX
The minimum radix available for conversion to and from strings.
|
static int |
MIN_SUPPLEMENTARY_CODE_POINT
The minimum value of a
Unicode supplementary code point, constant
U+10000. |
static char |
MIN_SURROGATE
The minimum value of a Unicode surrogate code unit in the
UTF-16 encoding, constant
'\uD800'. |
static char |
MIN_VALUE
The constant value of this field is the smallest value of type
char, '\u0000'. |
static byte |
MODIFIER_LETTER
General category "Lm" in the Unicode specification.
|
static byte |
MODIFIER_SYMBOL
General category "Sk" in the Unicode specification.
|
static byte |
NON_SPACING_MARK
General category "Mn" in the Unicode specification.
|
static byte |
OTHER_LETTER
General category "Lo" in the Unicode specification.
|
static byte |
OTHER_NUMBER
General category "No" in the Unicode specification.
|
static byte |
OTHER_PUNCTUATION
General category "Po" in the Unicode specification.
|
static byte |
OTHER_SYMBOL
General category "So" in the Unicode specification.
|
static byte |
PARAGRAPH_SEPARATOR
General category "Zp" in the Unicode specification.
|
static byte |
PRIVATE_USE
General category "Co" in the Unicode specification.
|
static int |
SIZE
The number of bits used to represent a char value in unsigned
binary form, constant
16. |
static byte |
SPACE_SEPARATOR
General category "Zs" in the Unicode specification.
|
static byte |
START_PUNCTUATION
General category "Ps" in the Unicode specification.
|
static byte |
SURROGATE
General category "Cs" in the Unicode specification.
|
static byte |
TITLECASE_LETTER
General category "Lt" in the Unicode specification.
|
static Class<Character> |
TYPE
The
Class instance representing the primitive type
char. |
static byte |
UNASSIGNED
General category "Cn" in the Unicode specification.
|
static byte |
UPPERCASE_LETTER
General category "Lu" in the Unicode specification.
|
| Constructor and Description |
|---|
Character(char value)
Constructs a newly allocated
Character object that
represents the specified char value. |
| Modifier and Type | Method and Description |
|---|---|
static int |
charCount(int codePoint)
Determines the number of
char values needed to
represent the specified character (Unicode code point). |
char |
charValue()
Returns the value of this
Character object. |
static int |
codePointAt(char[] a,
int index)
Returns the code point at the given index of the
char array. |
static int |
codePointAt(char[] a,
int index,
int limit)
Returns the code point at the given index of the
char array, where only array elements with
index less than limit can be used. |
static int |
codePointAt(CharSequence seq,
int index)
Returns the code point at the given index of the
CharSequence. |
static int |
codePointBefore(char[] a,
int index)
Returns the code point preceding the given index of the
char array. |
static int |
codePointBefore(char[] a,
int index,
int start)
Returns the code point preceding the given index of the
char array, where only array elements with
index greater than or equal to start
can be used. |
static int |
codePointBefore(CharSequence seq,
int index)
Returns the code point preceding the given index of the
CharSequence. |
static int |
codePointCount(char[] a,
int offset,
int count)
Returns the number of Unicode code points in a subarray of the
char array argument. |
static int |
codePointCount(CharSequence seq,
int beginIndex,
int endIndex)
Returns the number of Unicode code points in the text range of
the specified char sequence.
|
static int |
compare(char x,
char y)
Compares two
char values numerically. |
int |
compareTo(Character anotherCharacter)
Compares two
Character objects numerically. |
static int |
digit(char ch,
int radix)
Returns the numeric value of the character
ch in the
specified radix. |
static int |
digit(int codePoint,
int radix)
Returns the numeric value of the specified character (Unicode
code point) in the specified radix.
|
boolean |
equals(Object obj)
Compares this object against the specified object.
|
static char |
forDigit(int digit,
int radix)
Determines the character representation for a specific digit in
the specified radix.
|
static byte |
getDirectionality(char ch)
Returns the Unicode directionality property for the given
character.
|
static byte |
getDirectionality(int codePoint)
Returns the Unicode directionality property for the given
character (Unicode code point).
|
static String |
getName(int codePoint)
Returns the Unicode name of the specified character
codePoint, or null if the code point is
unassigned. |
static int |
getNumericValue(char ch)
Returns the
int value that the specified Unicode
character represents. |
static int |
getNumericValue(int codePoint)
Returns the
int value that the specified
character (Unicode code point) represents. |
static int |
getType(char ch)
Returns a value indicating a character's general category.
|
static int |
getType(int codePoint)
Returns a value indicating a character's general category.
|
int |
hashCode()
Returns a hash code for this
Character; equal to the result
of invoking charValue(). |
static int |
hashCode(char value)
Returns a hash code for a
char value; compatible with
Character.hashCode(). |
static char |
highSurrogate(int codePoint)
Returns the leading surrogate (a
high surrogate code unit) of the
surrogate pair
representing the specified supplementary character (Unicode
code point) in the UTF-16 encoding.
|
static boolean |
isAlphabetic(int codePoint)
Determines if the specified character (Unicode code point) is an alphabet.
|
static boolean |
isBmpCodePoint(int codePoint)
Determines whether the specified character (Unicode code point)
is in the Basic Multilingual Plane (BMP).
|
static boolean |
isDefined(char ch)
Determines if a character is defined in Unicode.
|
static boolean |
isDefined(int codePoint)
Determines if a character (Unicode code point) is defined in Unicode.
|
static boolean |
isDigit(char ch)
Determines if the specified character is a digit.
|
static boolean |
isDigit(int codePoint)
Determines if the specified character (Unicode code point) is a digit.
|
static boolean |
isHighSurrogate(char ch)
Determines if the given
char value is a
Unicode high-surrogate code unit
(also known as leading-surrogate code unit). |
static boolean |
isIdentifierIgnorable(char ch)
Determines if the specified character should be regarded as
an ignorable character in a Java identifier or a Unicode identifier.
|
static boolean |
isIdentifierIgnorable(int codePoint)
Determines if the specified character (Unicode code point) should be regarded as
an ignorable character in a Java identifier or a Unicode identifier.
|
static boolean |
isIdeographic(int codePoint)
Determines if the specified character (Unicode code point) is a CJKV
(Chinese, Japanese, Korean and Vietnamese) ideograph, as defined by
the Unicode Standard.
|
static boolean |
isISOControl(char ch)
Determines if the specified character is an ISO control
character.
|
static boolean |
isISOControl(int codePoint)
Determines if the referenced character (Unicode code point) is an ISO control
character.
|
static boolean |
isJavaIdentifierPart(char ch)
Determines if the specified character may be part of a Java
identifier as other than the first character.
|
static boolean |
isJavaIdentifierPart(int codePoint)
Determines if the character (Unicode code point) may be part of a Java
identifier as other than the first character.
|
static boolean |
isJavaIdentifierStart(char ch)
Determines if the specified character is
permissible as the first character in a Java identifier.
|
static boolean |
isJavaIdentifierStart(int codePoint)
Determines if the character (Unicode code point) is
permissible as the first character in a Java identifier.
|
static boolean |
isJavaLetter(char ch)
Deprecated.
Replaced by isJavaIdentifierStart(char).
|
static boolean |
isJavaLetterOrDigit(char ch)
Deprecated.
Replaced by isJavaIdentifierPart(char).
|
static boolean |
isLetter(char ch)
Determines if the specified character is a letter.
|
static boolean |
isLetter(int codePoint)
Determines if the specified character (Unicode code point) is a letter.
|
static boolean |
isLetterOrDigit(char ch)
Determines if the specified character is a letter or digit.
|
static boolean |
isLetterOrDigit(int codePoint)
Determines if the specified character (Unicode code point) is a letter or digit.
|
static boolean |
isLowerCase(char ch)
Determines if the specified character is a lowercase character.
|
static boolean |
isLowerCase(int codePoint)
Determines if the specified character (Unicode code point) is a
lowercase character.
|
static boolean |
isLowSurrogate(char ch)
Determines if the given
char value is a
Unicode low-surrogate code unit
(also known as trailing-surrogate code unit). |
static boolean |
isMirrored(char ch)
Determines whether the character is mirrored according to the
Unicode specification.
|
static boolean |
isMirrored(int codePoint)
Determines whether the specified character (Unicode code point)
is mirrored according to the Unicode specification.
|
static boolean |
isSpace(char ch)
Deprecated.
Replaced by isWhitespace(char).
|
static boolean |
isSpaceChar(char ch)
Determines if the specified character is a Unicode space character.
|
static boolean |
isSpaceChar(int codePoint)
Determines if the specified character (Unicode code point) is a
Unicode space character.
|
static boolean |
isSupplementaryCodePoint(int codePoint)
Determines whether the specified character (Unicode code point)
is in the supplementary character range.
|
static boolean |
isSurrogate(char ch)
Determines if the given
char value is a Unicode
surrogate code unit. |
static boolean |
isSurrogatePair(char high,
char low)
Determines whether the specified pair of
char
values is a valid
Unicode surrogate pair. |
static boolean |
isTitleCase(char ch)
Determines if the specified character is a titlecase character.
|
static boolean |
isTitleCase(int codePoint)
Determines if the specified character (Unicode code point) is a titlecase character.
|
static boolean |
isUnicodeIdentifierPart(char ch)
Determines if the specified character may be part of a Unicode
identifier as other than the first character.
|
static boolean |
isUnicodeIdentifierPart(int codePoint)
Determines if the specified character (Unicode code point) may be part of a Unicode
identifier as other than the first character.
|
static boolean |
isUnicodeIdentifierStart(char ch)
Determines if the specified character is permissible as the
first character in a Unicode identifier.
|
static boolean |
isUnicodeIdentifierStart(int codePoint)
Determines if the specified character (Unicode code point) is permissible as the
first character in a Unicode identifier.
|
static boolean |
isUpperCase(char ch)
Determines if the specified character is an uppercase character.
|
static boolean |
isUpperCase(int codePoint)
Determines if the specified character (Unicode code point) is an uppercase character.
|
static boolean |
isValidCodePoint(int codePoint)
Determines whether the specified code point is a valid
Unicode code point value.
|
static boolean |
isWhitespace(char ch)
Determines if the specified character is white space according to Java.
|
static boolean |
isWhitespace(int codePoint)
Determines if the specified character (Unicode code point) is
white space according to Java.
|
static char |
lowSurrogate(int codePoint)
Returns the trailing surrogate (a
low surrogate code unit) of the
surrogate pair
representing the specified supplementary character (Unicode
code point) in the UTF-16 encoding.
|
static int |
offsetByCodePoints(char[] a,
int start,
int count,
int index,
int codePointOffset)
Returns the index within the given
char subarray
that is offset from the given index by
codePointOffset code points. |
static int |
offsetByCodePoints(CharSequence seq,
int index,
int codePointOffset)
Returns the index within the given char sequence that is offset
from the given
index by codePointOffset
code points. |
static char |
reverseBytes(char ch)
Returns the value obtained by reversing the order of the bytes in the
specified char value.
|
static char[] |
toChars(int codePoint)
Converts the specified character (Unicode code point) to its
UTF-16 representation stored in a
char array. |
static int |
toChars(int codePoint,
char[] dst,
int dstIndex)
Converts the specified character (Unicode code point) to its
UTF-16 representation.
|
static int |
toCodePoint(char high,
char low)
Converts the specified surrogate pair to its supplementary code
point value.
|
static char |
toLowerCase(char ch)
Converts the character argument to lowercase using case
mapping information from the UnicodeData file.
|
static int |
toLowerCase(int codePoint)
Converts the character (Unicode code point) argument to
lowercase using case mapping information from the UnicodeData
file.
|
String |
toString()
Returns a
String object representing this
Character's value. |
static String |
toString(char c)
Returns a
String object representing the
specified char. |
static char |
toTitleCase(char ch)
Converts the character argument to titlecase using case mapping
information from the UnicodeData file.
|
static int |
toTitleCase(int codePoint)
Converts the character (Unicode code point) argument to titlecase using case mapping
information from the UnicodeData file.
|
static char |
toUpperCase(char ch)
Converts the character argument to uppercase using case mapping
information from the UnicodeData file.
|
static int |
toUpperCase(int codePoint)
Converts the character (Unicode code point) argument to
uppercase using case mapping information from the UnicodeData
file.
|
static Character |
valueOf(char c)
Returns a Character instance representing the specified
char value.
|
public static final int MIN_RADIX
digit method, the forDigit method, and the
toString method of class Integer.public static final int MAX_RADIX
digit method, the forDigit method, and the
toString method of class Integer.public static final char MIN_VALUE
char, '\u0000'.public static final char MAX_VALUE
char, '\uFFFF'.public static final Class<Character> TYPE
Class instance representing the primitive type
char.public static final byte UNASSIGNED
public static final byte UPPERCASE_LETTER
public static final byte LOWERCASE_LETTER
public static final byte TITLECASE_LETTER
public static final byte MODIFIER_LETTER
public static final byte OTHER_LETTER
public static final byte NON_SPACING_MARK
public static final byte ENCLOSING_MARK
public static final byte COMBINING_SPACING_MARK
public static final byte DECIMAL_DIGIT_NUMBER
public static final byte LETTER_NUMBER
public static final byte OTHER_NUMBER
public static final byte SPACE_SEPARATOR
public static final byte LINE_SEPARATOR
public static final byte PARAGRAPH_SEPARATOR
public static final byte CONTROL
public static final byte FORMAT
public static final byte PRIVATE_USE
public static final byte SURROGATE
public static final byte DASH_PUNCTUATION
public static final byte START_PUNCTUATION
public static final byte END_PUNCTUATION
public static final byte CONNECTOR_PUNCTUATION
public static final byte OTHER_PUNCTUATION
public static final byte MATH_SYMBOL
public static final byte CURRENCY_SYMBOL
public static final byte MODIFIER_SYMBOL
public static final byte OTHER_SYMBOL
public static final byte INITIAL_QUOTE_PUNCTUATION
public static final byte FINAL_QUOTE_PUNCTUATION
public static final byte DIRECTIONALITY_UNDEFINED
char
values have undefined directionality in the Unicode specification.public static final byte DIRECTIONALITY_LEFT_TO_RIGHT
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC
public static final byte DIRECTIONALITY_EUROPEAN_NUMBER
public static final byte DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
public static final byte DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
public static final byte DIRECTIONALITY_ARABIC_NUMBER
public static final byte DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
public static final byte DIRECTIONALITY_NONSPACING_MARK
public static final byte DIRECTIONALITY_BOUNDARY_NEUTRAL
public static final byte DIRECTIONALITY_PARAGRAPH_SEPARATOR
public static final byte DIRECTIONALITY_SEGMENT_SEPARATOR
public static final byte DIRECTIONALITY_WHITESPACE
public static final byte DIRECTIONALITY_OTHER_NEUTRALS
public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING
public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE
public static final byte DIRECTIONALITY_POP_DIRECTIONAL_FORMAT
public static final char MIN_HIGH_SURROGATE
'\uD800'.
A high-surrogate is also known as a leading-surrogate.public static final char MAX_HIGH_SURROGATE
'\uDBFF'.
A high-surrogate is also known as a leading-surrogate.public static final char MIN_LOW_SURROGATE
'\uDC00'.
A low-surrogate is also known as a trailing-surrogate.public static final char MAX_LOW_SURROGATE
'\uDFFF'.
A low-surrogate is also known as a trailing-surrogate.public static final char MIN_SURROGATE
'\uD800'.public static final char MAX_SURROGATE
'\uDFFF'.public static final int MIN_SUPPLEMENTARY_CODE_POINT
U+10000.public static final int MIN_CODE_POINT
U+0000.public static final int MAX_CODE_POINT
U+10FFFF.public static final int SIZE
16.public static final int BYTES
char value in unsigned
binary form.public Character(char value)
Character object that
represents the specified char value.value - the value to be represented by the
Character object.public static Character valueOf(char c)
Character(char), as this method is likely to yield
significantly better space and time performance by caching
frequently requested values.
This method will always cache values in the range '\u0000' to '\u007F', inclusive, and may
cache other values outside of this range.c - a char value.public char charValue()
Character object.char value represented by
this object.public int hashCode()
Character; equal to the result
of invoking charValue().hashCode in class ObjectCharacterObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public static int hashCode(char value)
char value; compatible with
Character.hashCode().value - The char for which to return a hash code.char value.public boolean equals(Object obj)
true if and only if the argument is not
null and is a Character object that
represents the same char value as this object.equals in class Objectobj - the object to compare with.true if the objects are the same;
false otherwise.Object.hashCode(),
HashMappublic String toString()
String object representing this
Character's value. The result is a string of
length 1 whose sole component is the primitive
char value represented by this
Character object.public static String toString(char c)
String object representing the
specified char. The result is a string of length
1 consisting solely of the specified char.c - the char to be convertedcharpublic static boolean isValidCodePoint(int codePoint)
codePoint - the Unicode code point to be testedtrue if the specified code point value is between
MIN_CODE_POINT and
MAX_CODE_POINT inclusive;
false otherwise.public static boolean isBmpCodePoint(int codePoint)
char.public static boolean isSupplementaryCodePoint(int codePoint)
codePoint - the character (Unicode code point) to be testedtrue if the specified code point is between
MIN_SUPPLEMENTARY_CODE_POINT and
MAX_CODE_POINT inclusive;
false otherwise.public static boolean isHighSurrogate(char ch)
char value is a
Unicode high-surrogate code unit
(also known as leading-surrogate code unit).
Such values do not represent characters by themselves, but are used in the representation of supplementary characters in the UTF-16 encoding.
ch - the char value to be tested.true if the char value is between
MIN_HIGH_SURROGATE and
MAX_HIGH_SURROGATE inclusive;
false otherwise.isLowSurrogate(char),
Character.UnicodeBlock.of(int)public static boolean isLowSurrogate(char ch)
char value is a
Unicode low-surrogate code unit
(also known as trailing-surrogate code unit).
Such values do not represent characters by themselves, but are used in the representation of supplementary characters in the UTF-16 encoding.
ch - the char value to be tested.true if the char value is between
MIN_LOW_SURROGATE and
MAX_LOW_SURROGATE inclusive;
false otherwise.isHighSurrogate(char)public static boolean isSurrogate(char ch)
char value is a Unicode
surrogate code unit.
Such values do not represent characters by themselves, but are used in the representation of supplementary characters in the UTF-16 encoding.
A char value is a surrogate code unit if and only if it is either a low-surrogate code unit or a high-surrogate code unit.
ch - the char value to be tested.true if the char value is between
MIN_SURROGATE and
MAX_SURROGATE inclusive;
false otherwise.public static boolean isSurrogatePair(char high,
char low)
char
values is a valid
Unicode surrogate pair.
This method is equivalent to the expression:
isHighSurrogate(high) && isLowSurrogate(low)
high - the high-surrogate code value to be testedlow - the low-surrogate code value to be testedtrue if the specified high and
low-surrogate code values represent a valid surrogate pair;
false otherwise.public static int charCount(int codePoint)
char values needed to
represent the specified character (Unicode code point). If the
specified character is equal to or greater than 0x10000, then
the method returns 2. Otherwise, the method returns 1.
This method doesn't validate the specified character to be a
valid Unicode code point. The caller must validate the
character value using isValidCodePoint
if necessary.
codePoint - the character (Unicode code point) to be tested.isSupplementaryCodePoint(int)public static int toCodePoint(char high,
char low)
isSurrogatePair if necessary.high - the high-surrogate code unitlow - the low-surrogate code unitpublic static int codePointAt(CharSequence seq, int index)
CharSequence. If the char value at
the given index in the CharSequence is in the
high-surrogate range, the following index is less than the
length of the CharSequence, and the
char value at the following index is in the
low-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at the given index is returned.seq - a sequence of char values (Unicode code
units)index - the index to the char values (Unicode
code units) in seq to be convertedNullPointerException - if seq is null.IndexOutOfBoundsException - if the value
index is negative or not less than
seq.length().public static int codePointAt(char[] a,
int index)
char array. If the char value at
the given index in the char array is in the
high-surrogate range, the following index is less than the
length of the char array, and the
char value at the following index is in the
low-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at the given index is returned.a - the char arrayindex - the index to the char values (Unicode
code units) in the char array to be convertedNullPointerException - if a is null.IndexOutOfBoundsException - if the value
index is negative or not less than
the length of the char array.public static int codePointAt(char[] a,
int index,
int limit)
char array, where only array elements with
index less than limit can be used. If
the char value at the given index in the
char array is in the high-surrogate range, the
following index is less than the limit, and the
char value at the following index is in the
low-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at the given index is returned.a - the char arrayindex - the index to the char values (Unicode
code units) in the char array to be convertedlimit - the index after the last array element that
can be used in the char arrayNullPointerException - if a is null.IndexOutOfBoundsException - if the index
argument is negative or not less than the limit
argument, or if the limit argument is negative or
greater than the length of the char array.public static int codePointBefore(CharSequence seq, int index)
CharSequence. If the char value at
(index - 1) in the CharSequence is in
the low-surrogate range, (index - 2) is not
negative, and the char value at (index - 2)
in the CharSequence is in the
high-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at (index - 1) is
returned.seq - the CharSequence instanceindex - the index following the code point that should be returnedNullPointerException - if seq is null.IndexOutOfBoundsException - if the index
argument is less than 1 or greater than seq.length().public static int codePointBefore(char[] a,
int index)
char array. If the char value at
(index - 1) in the char array is in
the low-surrogate range, (index - 2) is not
negative, and the char value at (index - 2)
in the char array is in the
high-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at (index - 1) is
returned.a - the char arrayindex - the index following the code point that should be returnedNullPointerException - if a is null.IndexOutOfBoundsException - if the index
argument is less than 1 or greater than the length of the
char arraypublic static int codePointBefore(char[] a,
int index,
int start)
char array, where only array elements with
index greater than or equal to start
can be used. If the char value at (index - 1)
in the char array is in the
low-surrogate range, (index - 2) is not less than
start, and the char value at
(index - 2) in the char array is in
the high-surrogate range, then the supplementary code point
corresponding to this surrogate pair is returned. Otherwise,
the char value at (index - 1) is
returned.a - the char arrayindex - the index following the code point that should be returnedstart - the index of the first array element in the
char arrayNullPointerException - if a is null.IndexOutOfBoundsException - if the index
argument is not greater than the start argument or
is greater than the length of the char array, or
if the start argument is negative or not less than
the length of the char array.public static char highSurrogate(int codePoint)
char is returned.
If
isSupplementaryCodePoint(x)
is true, then
isHighSurrogate(highSurrogate(x)) and
toCodePoint(highSurrogate(x), lowSurrogate(x)) == x
are also always true.
codePoint - a supplementary character (Unicode code point)public static char lowSurrogate(int codePoint)
char is returned.
If
isSupplementaryCodePoint(x)
is true, then
isLowSurrogate(lowSurrogate(x)) and
toCodePoint(highSurrogate(x), lowSurrogate(x)) == x
are also always true.
codePoint - a supplementary character (Unicode code point)public static int toChars(int codePoint,
char[] dst,
int dstIndex)
dst[dstIndex], and 1 is returned. If the
specified code point is a supplementary character, its
surrogate values are stored in dst[dstIndex]
(high-surrogate) and dst[dstIndex+1]
(low-surrogate), and 2 is returned.codePoint - the character (Unicode code point) to be converted.dst - an array of char in which the
codePoint's UTF-16 value is stored.dstIndex - the start index into the dst
array where the converted value is stored.IllegalArgumentException - if the specified
codePoint is not a valid Unicode code point.NullPointerException - if the specified dst is null.IndexOutOfBoundsException - if dstIndex
is negative or not less than dst.length, or if
dst at dstIndex doesn't have enough
array element(s) to store the resulting char
value(s). (If dstIndex is equal to
dst.length-1 and the specified
codePoint is a supplementary character, the
high-surrogate value is not stored in
dst[dstIndex].)public static char[] toChars(int codePoint)
char array. If
the specified code point is a BMP (Basic Multilingual Plane or
Plane 0) value, the resulting char array has
the same value as codePoint. If the specified code
point is a supplementary code point, the resulting
char array has the corresponding surrogate pair.codePoint - a Unicode code pointchar array having
codePoint's UTF-16 representation.IllegalArgumentException - if the specified
codePoint is not a valid Unicode code point.public static int codePointCount(CharSequence seq, int beginIndex, int endIndex)
beginIndex and extends to the
char at index endIndex - 1. Thus the
length (in chars) of the text range is
endIndex-beginIndex. Unpaired surrogates within
the text range count as one code point each.seq - the char sequencebeginIndex - the index to the first char of
the text range.endIndex - the index after the last char of
the text range.NullPointerException - if seq is null.IndexOutOfBoundsException - if the
beginIndex is negative, or endIndex
is larger than the length of the given sequence, or
beginIndex is larger than endIndex.public static int codePointCount(char[] a,
int offset,
int count)
char array argument. The offset
argument is the index of the first char of the
subarray and the count argument specifies the
length of the subarray in chars. Unpaired
surrogates within the subarray count as one code point each.a - the char arrayoffset - the index of the first char in the
given char arraycount - the length of the subarray in charsNullPointerException - if a is null.IndexOutOfBoundsException - if offset or
count is negative, or if offset +
count is larger than the length of the given array.public static int offsetByCodePoints(CharSequence seq, int index, int codePointOffset)
index by codePointOffset
code points. Unpaired surrogates within the text range given by
index and codePointOffset count as
one code point each.seq - the char sequenceindex - the index to be offsetcodePointOffset - the offset in code pointsNullPointerException - if seq is null.IndexOutOfBoundsException - if index
is negative or larger then the length of the char sequence,
or if codePointOffset is positive and the
subsequence starting with index has fewer than
codePointOffset code points, or if
codePointOffset is negative and the subsequence
before index has fewer than the absolute value
of codePointOffset code points.public static int offsetByCodePoints(char[] a,
int start,
int count,
int index,
int codePointOffset)
char subarray
that is offset from the given index by
codePointOffset code points. The
start and count arguments specify a
subarray of the char array. Unpaired surrogates
within the text range given by index and
codePointOffset count as one code point each.a - the char arraystart - the index of the first char of the
subarraycount - the length of the subarray in charsindex - the index to be offsetcodePointOffset - the offset in code pointsNullPointerException - if a is null.IndexOutOfBoundsException - if start or count is negative,
or if start + count is larger than the length of
the given array,
or if index is less than start or
larger then start + count,
or if codePointOffset is positive and the text range
starting with index and ending with start + count - 1
has fewer than codePointOffset code
points,
or if codePointOffset is negative and the text range
starting with start and ending with index - 1
has fewer than the absolute value of
codePointOffset code points.public static boolean isLowerCase(char ch)
A character is lowercase if its general category type, provided
by Character.getType(ch), is
LOWERCASE_LETTER, or it has contributory property
Other_Lowercase as defined by the Unicode Standard.
The following are examples of lowercase characters:
a b c d e f g h i j k l m n o p q r s t u v w x y z '\u00DF' '\u00E0' '\u00E1' '\u00E2' '\u00E3' '\u00E4' '\u00E5' '\u00E6' '\u00E7' '\u00E8' '\u00E9' '\u00EA' '\u00EB' '\u00EC' '\u00ED' '\u00EE' '\u00EF' '\u00F0' '\u00F1' '\u00F2' '\u00F3' '\u00F4' '\u00F5' '\u00F6' '\u00F8' '\u00F9' '\u00FA' '\u00FB' '\u00FC' '\u00FD' '\u00FE' '\u00FF'
Many other Unicode characters are lowercase too.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isLowerCase(int) method.
ch - the character to be tested.true if the character is lowercase;
false otherwise.isLowerCase(char),
isTitleCase(char),
toLowerCase(char),
getType(char)public static boolean isLowerCase(int codePoint)
A character is lowercase if its general category type, provided
by getType(codePoint), is
LOWERCASE_LETTER, or it has contributory property
Other_Lowercase as defined by the Unicode Standard.
The following are examples of lowercase characters:
a b c d e f g h i j k l m n o p q r s t u v w x y z '\u00DF' '\u00E0' '\u00E1' '\u00E2' '\u00E3' '\u00E4' '\u00E5' '\u00E6' '\u00E7' '\u00E8' '\u00E9' '\u00EA' '\u00EB' '\u00EC' '\u00ED' '\u00EE' '\u00EF' '\u00F0' '\u00F1' '\u00F2' '\u00F3' '\u00F4' '\u00F5' '\u00F6' '\u00F8' '\u00F9' '\u00FA' '\u00FB' '\u00FC' '\u00FD' '\u00FE' '\u00FF'
Many other Unicode characters are lowercase too.
codePoint - the character (Unicode code point) to be tested.true if the character is lowercase;
false otherwise.isLowerCase(int),
isTitleCase(int),
toLowerCase(int),
getType(int)public static boolean isUpperCase(char ch)
A character is uppercase if its general category type, provided by
Character.getType(ch), is UPPERCASE_LETTER.
or it has contributory property Other_Uppercase as defined by the Unicode Standard.
The following are examples of uppercase characters:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z '\u00C0' '\u00C1' '\u00C2' '\u00C3' '\u00C4' '\u00C5' '\u00C6' '\u00C7' '\u00C8' '\u00C9' '\u00CA' '\u00CB' '\u00CC' '\u00CD' '\u00CE' '\u00CF' '\u00D0' '\u00D1' '\u00D2' '\u00D3' '\u00D4' '\u00D5' '\u00D6' '\u00D8' '\u00D9' '\u00DA' '\u00DB' '\u00DC' '\u00DD' '\u00DE'
Many other Unicode characters are uppercase too.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isUpperCase(int) method.
ch - the character to be tested.true if the character is uppercase;
false otherwise.isLowerCase(char),
isTitleCase(char),
toUpperCase(char),
getType(char)public static boolean isUpperCase(int codePoint)
A character is uppercase if its general category type, provided by
getType(codePoint), is UPPERCASE_LETTER,
or it has contributory property Other_Uppercase as defined by the Unicode Standard.
The following are examples of uppercase characters:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z '\u00C0' '\u00C1' '\u00C2' '\u00C3' '\u00C4' '\u00C5' '\u00C6' '\u00C7' '\u00C8' '\u00C9' '\u00CA' '\u00CB' '\u00CC' '\u00CD' '\u00CE' '\u00CF' '\u00D0' '\u00D1' '\u00D2' '\u00D3' '\u00D4' '\u00D5' '\u00D6' '\u00D8' '\u00D9' '\u00DA' '\u00DB' '\u00DC' '\u00DD' '\u00DE'
Many other Unicode characters are uppercase too.
codePoint - the character (Unicode code point) to be tested.true if the character is uppercase;
false otherwise.isLowerCase(int),
isTitleCase(int),
toUpperCase(int),
getType(int)public static boolean isTitleCase(char ch)
A character is a titlecase character if its general
category type, provided by Character.getType(ch),
is TITLECASE_LETTER.
Some characters look like pairs of Latin letters. For example, there is an uppercase letter that looks like "LJ" and has a corresponding lowercase letter that looks like "lj". A third form, which looks like "Lj", is the appropriate form to use when rendering a word in lowercase with initial capitals, as for a book title.
These are some of the Unicode characters for which this method returns
true:
LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
LATIN CAPITAL LETTER L WITH SMALL LETTER J
LATIN CAPITAL LETTER N WITH SMALL LETTER J
LATIN CAPITAL LETTER D WITH SMALL LETTER Z
Many other Unicode characters are titlecase too.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isTitleCase(int) method.
ch - the character to be tested.true if the character is titlecase;
false otherwise.isLowerCase(char),
isUpperCase(char),
toTitleCase(char),
getType(char)public static boolean isTitleCase(int codePoint)
A character is a titlecase character if its general
category type, provided by getType(codePoint),
is TITLECASE_LETTER.
Some characters look like pairs of Latin letters. For example, there is an uppercase letter that looks like "LJ" and has a corresponding lowercase letter that looks like "lj". A third form, which looks like "Lj", is the appropriate form to use when rendering a word in lowercase with initial capitals, as for a book title.
These are some of the Unicode characters for which this method returns
true:
LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
LATIN CAPITAL LETTER L WITH SMALL LETTER J
LATIN CAPITAL LETTER N WITH SMALL LETTER J
LATIN CAPITAL LETTER D WITH SMALL LETTER Z
Many other Unicode characters are titlecase too.
codePoint - the character (Unicode code point) to be tested.true if the character is titlecase;
false otherwise.isLowerCase(int),
isUpperCase(int),
toTitleCase(int),
getType(int)public static boolean isDigit(char ch)
A character is a digit if its general category type, provided
by Character.getType(ch), is
DECIMAL_DIGIT_NUMBER.
Some Unicode character ranges that contain digits:
'\u0030' through '\u0039',
ISO-LATIN-1 digits ('0' through '9')
'\u0660' through '\u0669',
Arabic-Indic digits
'\u06F0' through '\u06F9',
Extended Arabic-Indic digits
'\u0966' through '\u096F',
Devanagari digits
'\uFF10' through '\uFF19',
Fullwidth digits
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isDigit(int) method.
ch - the character to be tested.true if the character is a digit;
false otherwise.digit(char, int),
forDigit(int, int),
getType(char)public static boolean isDigit(int codePoint)
A character is a digit if its general category type, provided
by getType(codePoint), is
DECIMAL_DIGIT_NUMBER.
Some Unicode character ranges that contain digits:
'\u0030' through '\u0039',
ISO-LATIN-1 digits ('0' through '9')
'\u0660' through '\u0669',
Arabic-Indic digits
'\u06F0' through '\u06F9',
Extended Arabic-Indic digits
'\u0966' through '\u096F',
Devanagari digits
'\uFF10' through '\uFF19',
Fullwidth digits
codePoint - the character (Unicode code point) to be tested.true if the character is a digit;
false otherwise.forDigit(int, int),
getType(int)public static boolean isDefined(char ch)
A character is defined if at least one of the following is true:
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isDefined(int) method.
ch - the character to be testedtrue if the character has a defined meaning
in Unicode; false otherwise.isDigit(char),
isLetter(char),
isLetterOrDigit(char),
isLowerCase(char),
isTitleCase(char),
isUpperCase(char)public static boolean isDefined(int codePoint)
A character is defined if at least one of the following is true:
codePoint - the character (Unicode code point) to be tested.true if the character has a defined meaning
in Unicode; false otherwise.isDigit(int),
isLetter(int),
isLetterOrDigit(int),
isLowerCase(int),
isTitleCase(int),
isUpperCase(int)public static boolean isLetter(char ch)
A character is considered to be a letter if its general
category type, provided by Character.getType(ch),
is any of the following:
UPPERCASE_LETTER
LOWERCASE_LETTER
TITLECASE_LETTER
MODIFIER_LETTER
OTHER_LETTER
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isLetter(int) method.
ch - the character to be tested.true if the character is a letter;
false otherwise.isDigit(char),
isJavaIdentifierStart(char),
isJavaLetter(char),
isJavaLetterOrDigit(char),
isLetterOrDigit(char),
isLowerCase(char),
isTitleCase(char),
isUnicodeIdentifierStart(char),
isUpperCase(char)public static boolean isLetter(int codePoint)
A character is considered to be a letter if its general
category type, provided by getType(codePoint),
is any of the following:
UPPERCASE_LETTER
LOWERCASE_LETTER
TITLECASE_LETTER
MODIFIER_LETTER
OTHER_LETTER
codePoint - the character (Unicode code point) to be tested.true if the character is a letter;
false otherwise.isDigit(int),
isJavaIdentifierStart(int),
isLetterOrDigit(int),
isLowerCase(int),
isTitleCase(int),
isUnicodeIdentifierStart(int),
isUpperCase(int)public static boolean isLetterOrDigit(char ch)
A character is considered to be a letter or digit if either
Character.isLetter(char ch) or
Character.isDigit(char ch) returns
true for the character.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isLetterOrDigit(int) method.
ch - the character to be tested.true if the character is a letter or digit;
false otherwise.isDigit(char),
isJavaIdentifierPart(char),
isJavaLetter(char),
isJavaLetterOrDigit(char),
isLetter(char),
isUnicodeIdentifierPart(char)public static boolean isLetterOrDigit(int codePoint)
A character is considered to be a letter or digit if either
isLetter(codePoint) or
isDigit(codePoint) returns
true for the character.
codePoint - the character (Unicode code point) to be tested.true if the character is a letter or digit;
false otherwise.isDigit(int),
isJavaIdentifierPart(int),
isLetter(int),
isUnicodeIdentifierPart(int)@Deprecated public static boolean isJavaLetter(char ch)
A character may start a Java identifier if and only if one of the following is true:
isLetter(ch) returns true
getType(ch) returns LETTER_NUMBER
ch is a currency symbol (such as '$')
ch is a connecting punctuation character (such as '_').
ch - the character to be tested.true if the character may start a Java
identifier; false otherwise.isJavaLetterOrDigit(char),
isJavaIdentifierStart(char),
isJavaIdentifierPart(char),
isLetter(char),
isLetterOrDigit(char),
isUnicodeIdentifierStart(char)@Deprecated public static boolean isJavaLetterOrDigit(char ch)
A character may be part of a Java identifier if and only if any of the following are true:
'$')
'_')
isIdentifierIgnorable returns
true for the character.
ch - the character to be tested.true if the character may be part of a
Java identifier; false otherwise.isJavaLetter(char),
isJavaIdentifierStart(char),
isJavaIdentifierPart(char),
isLetter(char),
isLetterOrDigit(char),
isUnicodeIdentifierPart(char),
isIdentifierIgnorable(char)public static boolean isAlphabetic(int codePoint)
A character is considered to be alphabetic if its general category type,
provided by getType(codePoint), is any of
the following:
UPPERCASE_LETTER
LOWERCASE_LETTER
TITLECASE_LETTER
MODIFIER_LETTER
OTHER_LETTER
LETTER_NUMBER
codePoint - the character (Unicode code point) to be tested.true if the character is a Unicode alphabet
character, false otherwise.public static boolean isIdeographic(int codePoint)
codePoint - the character (Unicode code point) to be tested.true if the character is a Unicode ideograph
character, false otherwise.public static boolean isJavaIdentifierStart(char ch)
A character may start a Java identifier if and only if one of the following conditions is true:
isLetter(ch) returns true
getType(ch) returns LETTER_NUMBER
ch is a currency symbol (such as '$')
ch is a connecting punctuation character (such as '_').
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isJavaIdentifierStart(int) method.
ch - the character to be tested.true if the character may start a Java identifier;
false otherwise.isJavaIdentifierPart(char),
isLetter(char),
isUnicodeIdentifierStart(char),
SourceVersion.isIdentifier(CharSequence)public static boolean isJavaIdentifierStart(int codePoint)
A character may start a Java identifier if and only if one of the following conditions is true:
isLetter(codePoint)
returns true
getType(codePoint)
returns LETTER_NUMBER
'$')
'_').
codePoint - the character (Unicode code point) to be tested.true if the character may start a Java identifier;
false otherwise.isJavaIdentifierPart(int),
isLetter(int),
isUnicodeIdentifierStart(int),
SourceVersion.isIdentifier(CharSequence)public static boolean isJavaIdentifierPart(char ch)
A character may be part of a Java identifier if any of the following are true:
'$')
'_')
isIdentifierIgnorable returns
true for the character
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isJavaIdentifierPart(int) method.
ch - the character to be tested.true if the character may be part of a
Java identifier; false otherwise.isIdentifierIgnorable(char),
isJavaIdentifierStart(char),
isLetterOrDigit(char),
isUnicodeIdentifierPart(char),
SourceVersion.isIdentifier(CharSequence)public static boolean isJavaIdentifierPart(int codePoint)
A character may be part of a Java identifier if any of the following are true:
'$')
'_')
isIdentifierIgnorable(codePoint) returns true for
the character
codePoint - the character (Unicode code point) to be tested.true if the character may be part of a
Java identifier; false otherwise.isIdentifierIgnorable(int),
isJavaIdentifierStart(int),
isLetterOrDigit(int),
isUnicodeIdentifierPart(int),
SourceVersion.isIdentifier(CharSequence)public static boolean isUnicodeIdentifierStart(char ch)
A character may start a Unicode identifier if and only if one of the following conditions is true:
isLetter(ch) returns true
getType(ch) returns
LETTER_NUMBER.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isUnicodeIdentifierStart(int) method.
ch - the character to be tested.true if the character may start a Unicode
identifier; false otherwise.isJavaIdentifierStart(char),
isLetter(char),
isUnicodeIdentifierPart(char)public static boolean isUnicodeIdentifierStart(int codePoint)
A character may start a Unicode identifier if and only if one of the following conditions is true:
isLetter(codePoint)
returns true
getType(codePoint)
returns LETTER_NUMBER.
codePoint - the character (Unicode code point) to be tested.true if the character may start a Unicode
identifier; false otherwise.isJavaIdentifierStart(int),
isLetter(int),
isUnicodeIdentifierPart(int)public static boolean isUnicodeIdentifierPart(char ch)
A character may be part of a Unicode identifier if and only if one of the following statements is true:
'_')
isIdentifierIgnorable returns
true for this character.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isUnicodeIdentifierPart(int) method.
ch - the character to be tested.true if the character may be part of a
Unicode identifier; false otherwise.isIdentifierIgnorable(char),
isJavaIdentifierPart(char),
isLetterOrDigit(char),
isUnicodeIdentifierStart(char)public static boolean isUnicodeIdentifierPart(int codePoint)
A character may be part of a Unicode identifier if and only if one of the following statements is true:
'_')
isIdentifierIgnorable returns
true for this character.
codePoint - the character (Unicode code point) to be tested.true if the character may be part of a
Unicode identifier; false otherwise.isIdentifierIgnorable(int),
isJavaIdentifierPart(int),
isLetterOrDigit(int),
isUnicodeIdentifierStart(int)public static boolean isIdentifierIgnorable(char ch)
The following Unicode characters are ignorable in a Java identifier or a Unicode identifier:
'\u0000' through '\u0008'
'\u000E' through '\u001B'
'\u007F' through '\u009F'
FORMAT general
category value
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isIdentifierIgnorable(int) method.
ch - the character to be tested.true if the character is an ignorable control
character that may be part of a Java or Unicode identifier;
false otherwise.isJavaIdentifierPart(char),
isUnicodeIdentifierPart(char)public static boolean isIdentifierIgnorable(int codePoint)
The following Unicode characters are ignorable in a Java identifier or a Unicode identifier:
'\u0000' through '\u0008'
'\u000E' through '\u001B'
'\u007F' through '\u009F'
FORMAT general
category value
codePoint - the character (Unicode code point) to be tested.true if the character is an ignorable control
character that may be part of a Java or Unicode identifier;
false otherwise.isJavaIdentifierPart(int),
isUnicodeIdentifierPart(int)public static char toLowerCase(char ch)
Note that
Character.isLowerCase(Character.toLowerCase(ch))
does not always return true for some ranges of
characters, particularly those that are symbols or ideographs.
In general, String.toLowerCase() should be used to map
characters to lowercase. String case mapping methods
have several benefits over Character case mapping methods.
String case mapping methods can perform locale-sensitive
mappings, context-sensitive mappings, and 1:M character mappings, whereas
the Character case mapping methods cannot.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the toLowerCase(int) method.
ch - the character to be converted.isLowerCase(char),
String.toLowerCase()public static int toLowerCase(int codePoint)
Note that
Character.isLowerCase(Character.toLowerCase(codePoint))
does not always return true for some ranges of
characters, particularly those that are symbols or ideographs.
In general, String.toLowerCase() should be used to map
characters to lowercase. String case mapping methods
have several benefits over Character case mapping methods.
String case mapping methods can perform locale-sensitive
mappings, context-sensitive mappings, and 1:M character mappings, whereas
the Character case mapping methods cannot.
codePoint - the character (Unicode code point) to be converted.isLowerCase(int),
String.toLowerCase()public static char toUpperCase(char ch)
Note that
Character.isUpperCase(Character.toUpperCase(ch))
does not always return true for some ranges of
characters, particularly those that are symbols or ideographs.
In general, String.toUpperCase() should be used to map
characters to uppercase. String case mapping methods
have several benefits over Character case mapping methods.
String case mapping methods can perform locale-sensitive
mappings, context-sensitive mappings, and 1:M character mappings, whereas
the Character case mapping methods cannot.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the toUpperCase(int) method.
ch - the character to be converted.isUpperCase(char),
String.toUpperCase()public static int toUpperCase(int codePoint)
Note that
Character.isUpperCase(Character.toUpperCase(codePoint))
does not always return true for some ranges of
characters, particularly those that are symbols or ideographs.
In general, String.toUpperCase() should be used to map
characters to uppercase. String case mapping methods
have several benefits over Character case mapping methods.
String case mapping methods can perform locale-sensitive
mappings, context-sensitive mappings, and 1:M character mappings, whereas
the Character case mapping methods cannot.
codePoint - the character (Unicode code point) to be converted.isUpperCase(int),
String.toUpperCase()public static char toTitleCase(char ch)
char argument is already a titlecase
char, the same char value will be
returned.
Note that
Character.isTitleCase(Character.toTitleCase(ch))
does not always return true for some ranges of
characters.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the toTitleCase(int) method.
ch - the character to be converted.isTitleCase(char),
toLowerCase(char),
toUpperCase(char)public static int toTitleCase(int codePoint)
Note that
Character.isTitleCase(Character.toTitleCase(codePoint))
does not always return true for some ranges of
characters.
codePoint - the character (Unicode code point) to be converted.isTitleCase(int),
toLowerCase(int),
toUpperCase(int)public static int digit(char ch,
int radix)
ch in the
specified radix.
If the radix is not in the range MIN_RADIX ≤
radix ≤ MAX_RADIX or if the
value of ch is not a valid digit in the specified
radix, -1 is returned. A character is a valid digit
if at least one of the following is true:
isDigit is true of the character
and the Unicode decimal digit value of the character (or its
single-character decomposition) is less than the specified radix.
In this case the decimal digit value is returned.
'A' through 'Z' and its code is less than
radix + 'A' - 10.
In this case, ch - 'A' + 10
is returned.
'a' through 'z' and its code is less than
radix + 'a' - 10.
In this case, ch - 'a' + 10
is returned.
'\uFF21') through Z ('\uFF3A')
and its code is less than
radix + '\uFF21' - 10.
In this case, ch - '\uFF21' + 10
is returned.
'\uFF41') through z ('\uFF5A')
and its code is less than
radix + '\uFF41' - 10.
In this case, ch - '\uFF41' + 10
is returned.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the digit(int, int) method.
ch - the character to be converted.radix - the radix.forDigit(int, int),
isDigit(char)public static int digit(int codePoint,
int radix)
If the radix is not in the range MIN_RADIX ≤
radix ≤ MAX_RADIX or if the
character is not a valid digit in the specified
radix, -1 is returned. A character is a valid digit
if at least one of the following is true:
isDigit(codePoint) is true of the character
and the Unicode decimal digit value of the character (or its
single-character decomposition) is less than the specified radix.
In this case the decimal digit value is returned.
'A' through 'Z' and its code is less than
radix + 'A' - 10.
In this case, codePoint - 'A' + 10
is returned.
'a' through 'z' and its code is less than
radix + 'a' - 10.
In this case, codePoint - 'a' + 10
is returned.
'\uFF21') through Z ('\uFF3A')
and its code is less than
radix + '\uFF21' - 10.
In this case,
codePoint - '\uFF21' + 10
is returned.
'\uFF41') through z ('\uFF5A')
and its code is less than
radix + '\uFF41'- 10.
In this case,
codePoint - '\uFF41' + 10
is returned.
codePoint - the character (Unicode code point) to be converted.radix - the radix.forDigit(int, int),
isDigit(int)public static int getNumericValue(char ch)
int value that the specified Unicode
character represents. For example, the character
'\u216C' (the roman numeral fifty) will return
an int with a value of 50.
The letters A-Z in their uppercase ('\u0041' through
'\u005A'), lowercase
('\u0061' through '\u007A'), and
full width variant ('\uFF21' through
'\uFF3A' and '\uFF41' through
'\uFF5A') forms have numeric values from 10
through 35. This is independent of the Unicode specification,
which does not assign numeric values to these char
values.
If the character does not have a numeric value, then -1 is returned. If the character has a numeric value that cannot be represented as a nonnegative integer (for example, a fractional value), then -2 is returned.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the getNumericValue(int) method.
ch - the character to be converted.int
value; -2 if the character has a numeric value that is not a
nonnegative integer; -1 if the character has no numeric value.forDigit(int, int),
isDigit(char)public static int getNumericValue(int codePoint)
int value that the specified
character (Unicode code point) represents. For example, the character
'\u216C' (the Roman numeral fifty) will return
an int with a value of 50.
The letters A-Z in their uppercase ('\u0041' through
'\u005A'), lowercase
('\u0061' through '\u007A'), and
full width variant ('\uFF21' through
'\uFF3A' and '\uFF41' through
'\uFF5A') forms have numeric values from 10
through 35. This is independent of the Unicode specification,
which does not assign numeric values to these char
values.
If the character does not have a numeric value, then -1 is returned. If the character has a numeric value that cannot be represented as a nonnegative integer (for example, a fractional value), then -2 is returned.
codePoint - the character (Unicode code point) to be converted.int
value; -2 if the character has a numeric value that is not a
nonnegative integer; -1 if the character has no numeric value.forDigit(int, int),
isDigit(int)@Deprecated public static boolean isSpace(char ch)
true for the following five
characters only:
'\t' | U+0009 |
HORIZONTAL TABULATION |
'\n' | U+000A |
NEW LINE |
'\f' | U+000C |
FORM FEED |
'\r' | U+000D |
CARRIAGE RETURN |
' ' | U+0020 |
SPACE |
ch - the character to be tested.true if the character is ISO-LATIN-1 white
space; false otherwise.isSpaceChar(char),
isWhitespace(char)public static boolean isSpaceChar(char ch)
SPACE_SEPARATOR
LINE_SEPARATOR
PARAGRAPH_SEPARATOR
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isSpaceChar(int) method.
ch - the character to be tested.true if the character is a space character;
false otherwise.isWhitespace(char)public static boolean isSpaceChar(int codePoint)
codePoint - the character (Unicode code point) to be tested.true if the character is a space character;
false otherwise.isWhitespace(int)public static boolean isWhitespace(char ch)
SPACE_SEPARATOR,
LINE_SEPARATOR, or PARAGRAPH_SEPARATOR)
but is not also a non-breaking space ('\u00A0',
'\u2007', '\u202F').
'\t', U+0009 HORIZONTAL TABULATION.
'\n', U+000A LINE FEED.
'\u000B', U+000B VERTICAL TABULATION.
'\f', U+000C FORM FEED.
'\r', U+000D CARRIAGE RETURN.
'\u001C', U+001C FILE SEPARATOR.
'\u001D', U+001D GROUP SEPARATOR.
'\u001E', U+001E RECORD SEPARATOR.
'\u001F', U+001F UNIT SEPARATOR.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isWhitespace(int) method.
ch - the character to be tested.true if the character is a Java whitespace
character; false otherwise.isSpaceChar(char)public static boolean isWhitespace(int codePoint)
SPACE_SEPARATOR,
LINE_SEPARATOR, or PARAGRAPH_SEPARATOR)
but is not also a non-breaking space ('\u00A0',
'\u2007', '\u202F').
'\t', U+0009 HORIZONTAL TABULATION.
'\n', U+000A LINE FEED.
'\u000B', U+000B VERTICAL TABULATION.
'\f', U+000C FORM FEED.
'\r', U+000D CARRIAGE RETURN.
'\u001C', U+001C FILE SEPARATOR.
'\u001D', U+001D GROUP SEPARATOR.
'\u001E', U+001E RECORD SEPARATOR.
'\u001F', U+001F UNIT SEPARATOR.
codePoint - the character (Unicode code point) to be tested.true if the character is a Java whitespace
character; false otherwise.isSpaceChar(int)public static boolean isISOControl(char ch)
'\u0000'
through '\u001F' or in the range
'\u007F' through '\u009F'.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isISOControl(int) method.
ch - the character to be tested.true if the character is an ISO control character;
false otherwise.isSpaceChar(char),
isWhitespace(char)public static boolean isISOControl(int codePoint)
'\u0000'
through '\u001F' or in the range
'\u007F' through '\u009F'.codePoint - the character (Unicode code point) to be tested.true if the character is an ISO control character;
false otherwise.isSpaceChar(int),
isWhitespace(int)public static int getType(char ch)
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the getType(int) method.
ch - the character to be tested.int representing the
character's general category.COMBINING_SPACING_MARK,
CONNECTOR_PUNCTUATION,
CONTROL,
CURRENCY_SYMBOL,
DASH_PUNCTUATION,
DECIMAL_DIGIT_NUMBER,
ENCLOSING_MARK,
END_PUNCTUATION,
FINAL_QUOTE_PUNCTUATION,
FORMAT,
INITIAL_QUOTE_PUNCTUATION,
LETTER_NUMBER,
LINE_SEPARATOR,
LOWERCASE_LETTER,
MATH_SYMBOL,
MODIFIER_LETTER,
MODIFIER_SYMBOL,
NON_SPACING_MARK,
OTHER_LETTER,
OTHER_NUMBER,
OTHER_PUNCTUATION,
OTHER_SYMBOL,
PARAGRAPH_SEPARATOR,
PRIVATE_USE,
SPACE_SEPARATOR,
START_PUNCTUATION,
SURROGATE,
TITLECASE_LETTER,
UNASSIGNED,
UPPERCASE_LETTERpublic static int getType(int codePoint)
codePoint - the character (Unicode code point) to be tested.int representing the
character's general category.COMBINING_SPACING_MARK,
CONNECTOR_PUNCTUATION,
CONTROL,
CURRENCY_SYMBOL,
DASH_PUNCTUATION,
DECIMAL_DIGIT_NUMBER,
ENCLOSING_MARK,
END_PUNCTUATION,
FINAL_QUOTE_PUNCTUATION,
FORMAT,
INITIAL_QUOTE_PUNCTUATION,
LETTER_NUMBER,
LINE_SEPARATOR,
LOWERCASE_LETTER,
MATH_SYMBOL,
MODIFIER_LETTER,
MODIFIER_SYMBOL,
NON_SPACING_MARK,
OTHER_LETTER,
OTHER_NUMBER,
OTHER_PUNCTUATION,
OTHER_SYMBOL,
PARAGRAPH_SEPARATOR,
PRIVATE_USE,
SPACE_SEPARATOR,
START_PUNCTUATION,
SURROGATE,
TITLECASE_LETTER,
UNASSIGNED,
UPPERCASE_LETTERpublic static char forDigit(int digit,
int radix)
radix is not a
valid radix, or the value of digit is not a valid
digit in the specified radix, the null character
('\u0000') is returned.
The radix argument is valid if it is greater than or
equal to MIN_RADIX and less than or equal to
MAX_RADIX. The digit argument is valid if
0 <= digit < radix.
If the digit is less than 10, then
'0' + digit is returned. Otherwise, the value
'a' + digit - 10 is returned.
digit - the number to convert to a character.radix - the radix.char representation of the specified digit
in the specified radix.MIN_RADIX,
MAX_RADIX,
digit(char, int)public static byte getDirectionality(char ch)
char values is DIRECTIONALITY_UNDEFINED.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the getDirectionality(int) method.
ch - char for which the directionality property
is requested.char value.DIRECTIONALITY_UNDEFINED,
DIRECTIONALITY_LEFT_TO_RIGHT,
DIRECTIONALITY_RIGHT_TO_LEFT,
DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC,
DIRECTIONALITY_EUROPEAN_NUMBER,
DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR,
DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR,
DIRECTIONALITY_ARABIC_NUMBER,
DIRECTIONALITY_COMMON_NUMBER_SEPARATOR,
DIRECTIONALITY_NONSPACING_MARK,
DIRECTIONALITY_BOUNDARY_NEUTRAL,
DIRECTIONALITY_PARAGRAPH_SEPARATOR,
DIRECTIONALITY_SEGMENT_SEPARATOR,
DIRECTIONALITY_WHITESPACE,
DIRECTIONALITY_OTHER_NEUTRALS,
DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING,
DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE,
DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING,
DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE,
DIRECTIONALITY_POP_DIRECTIONAL_FORMATpublic static byte getDirectionality(int codePoint)
DIRECTIONALITY_UNDEFINED.codePoint - the character (Unicode code point) for which
the directionality property is requested.DIRECTIONALITY_UNDEFINED,
DIRECTIONALITY_LEFT_TO_RIGHT,
DIRECTIONALITY_RIGHT_TO_LEFT,
DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC,
DIRECTIONALITY_EUROPEAN_NUMBER,
DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR,
DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR,
DIRECTIONALITY_ARABIC_NUMBER,
DIRECTIONALITY_COMMON_NUMBER_SEPARATOR,
DIRECTIONALITY_NONSPACING_MARK,
DIRECTIONALITY_BOUNDARY_NEUTRAL,
DIRECTIONALITY_PARAGRAPH_SEPARATOR,
DIRECTIONALITY_SEGMENT_SEPARATOR,
DIRECTIONALITY_WHITESPACE,
DIRECTIONALITY_OTHER_NEUTRALS,
DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING,
DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE,
DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING,
DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE,
DIRECTIONALITY_POP_DIRECTIONAL_FORMATpublic static boolean isMirrored(char ch)
'\u0028' LEFT
PARENTHESIS is semantically defined to be an opening
parenthesis. This will appear as a "(" in text that is
left-to-right but as a ")" in text that is right-to-left.
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isMirrored(int) method.
ch - char for which the mirrored property is requestedtrue if the char is mirrored, false
if the char is not mirrored or is not defined.public static boolean isMirrored(int codePoint)
'\u0028' LEFT PARENTHESIS is semantically
defined to be an opening parenthesis. This will appear
as a "(" in text that is left-to-right but as a ")" in text
that is right-to-left.codePoint - the character (Unicode code point) to be tested.true if the character is mirrored, false
if the character is not mirrored or is not defined.public int compareTo(Character anotherCharacter)
Character objects numerically.compareTo in interface Comparable<Character>anotherCharacter - the Character to be compared.0 if the argument Character
is equal to this Character; a value less than
0 if this Character is numerically less
than the Character argument; and a value greater than
0 if this Character is numerically greater
than the Character argument (unsigned comparison).
Note that this is strictly a numerical comparison; it is not
locale-dependent.public static int compare(char x,
char y)
char values numerically.
The value returned is identical to what would be returned by:
Character.valueOf(x).compareTo(Character.valueOf(y))
x - the first char to comparey - the second char to compare0 if x == y;
a value less than 0 if x < y; and
a value greater than 0 if x > ypublic static char reverseBytes(char ch)
ch - The char of which to reverse the byte order.public static String getName(int codePoint)
codePoint, or null if the code point is
unassigned.
Note: if the specified character is not assigned a name by the UnicodeData file (part of the Unicode Character Database maintained by the Unicode Consortium), the returned name is the same as the result of expression.
Character.UnicodeBlock.of(codePoint).toString().replace('_', ' ')
+ " "
+ Integer.toHexString(codePoint).toUpperCase(Locale.ENGLISH);
codePoint - the character (Unicode code point)IllegalArgumentException - if the specified
codePoint is not a valid Unicode
code point. Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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