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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.lang.Character
public final class Character
The 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 4.0.
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
2 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.
Nested Class Summary | |
---|---|
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. |
Field Summary | |
---|---|
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. |
static char |
MAX_HIGH_SURROGATE
The maximum value of a Unicode high-surrogate code unit in the UTF-16 encoding. |
static char |
MAX_LOW_SURROGATE
The maximum value of a Unicode low-surrogate code unit in the UTF-16 encoding. |
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. |
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. |
static char |
MIN_HIGH_SURROGATE
The minimum value of a Unicode high-surrogate code unit in the UTF-16 encoding. |
static char |
MIN_LOW_SURROGATE
The minimum value of a Unicode low-surrogate code unit in the UTF-16 encoding. |
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 supplementary code point. |
static char |
MIN_SURROGATE
The minimum value of a Unicode surrogate code unit in the UTF-16 encoding. |
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. |
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 Summary | |
---|---|
Character(char value)
Constructs a newly allocated Character object that
represents the specified char value. |
Method Summary | |
---|---|
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. |
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 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 . |
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
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 |
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
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 |
isSurrogatePair(char high,
char low)
Determines whether the specified pair of char
values is a valid 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 in the range of 0x0000 to
0x10FFFF inclusive. |
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 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. |
Methods inherited from class java.lang.Object |
---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Field Detail |
---|
public static final int MIN_RADIX
digit
method, the forDigit
method, and the toString
method of class
Integer
.
digit(char, int)
,
forDigit(int, int)
,
Integer.toString(int, int)
,
Integer.valueOf(java.lang.String)
,
Constant Field Valuespublic static final int MAX_RADIX
digit
method, the forDigit
method, and the toString
method of class
Integer
.
digit(char, int)
,
forDigit(int, int)
,
Integer.toString(int, int)
,
Integer.valueOf(java.lang.String)
,
Constant Field Valuespublic 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
public static final char MAX_HIGH_SURROGATE
public static final char MIN_LOW_SURROGATE
public static final char MAX_LOW_SURROGATE
public static final char MIN_SURROGATE
public static final char MAX_SURROGATE
public static final int MIN_SUPPLEMENTARY_CODE_POINT
public static final int MIN_CODE_POINT
public static final int MAX_CODE_POINT
public static final int SIZE
Constructor Detail |
---|
public Character(char value)
Character
object that
represents the specified char
value.
value
- the value to be represented by the
Character
object.Method Detail |
---|
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.
c
- a char value.
public char charValue()
Character
object.
char
value represented by
this object.public int hashCode()
Character
.
hashCode
in class Object
Object.equals(java.lang.Object)
,
Hashtable
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 Object
obj
- the object to compare with.
true
if the objects are the same;
false
otherwise.Object.hashCode()
,
Hashtable
public 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.
toString
in class 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 converted
char
public static boolean isValidCodePoint(int codePoint)
0x0000
to
0x10FFFF
inclusive. This method is equivalent to
the expression:
codePoint >= 0x0000 && codePoint <= 0x10FFFF
codePoint
- the Unicode code point to be tested
true
if the specified code point value
is a valid code point value;
false
otherwise.public static boolean isSupplementaryCodePoint(int codePoint)
codePoint >= 0x10000 && codePoint <= 0x10FFFF
codePoint
- the character (Unicode code point) to be tested
true
if the specified character is in the Unicode
supplementary character range; false
otherwise.public static boolean isHighSurrogate(char ch)
char
value is a
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.
This method returns true
if and only if
isch >= '\uD800' && ch <= '\uDBFF'
true
.
ch
- the char
value to be tested.
true
if the char
value
is between '\uD800' and '\uDBFF' inclusive;
false
otherwise.isLowSurrogate(char)
,
Character.UnicodeBlock.of(int)
public static boolean isLowSurrogate(char ch)
char
value is a
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.
This method returns true
if and only if
isch >= '\uDC00' && ch <= '\uDFFF'
true
.
ch
- the char
value to be tested.
true
if the char
value
is between '\uDC00' and '\uDFFF' inclusive;
false
otherwise.isHighSurrogate(char)
public static boolean isSurrogatePair(char high, char low)
char
values is a valid 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 tested
true
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 unit
public 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 converted
NullPointerException
- 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 converted
NullPointerException
- 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
array
NullPointerException
- 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 returned
NullPointerException
- 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 returned
NullPointerException
- 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
array
NullPointerException
- 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 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 point
char
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 char
s) 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 char
s. 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 char
s
NullPointerException
- 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 points
NullPointerException
- 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 char
sindex
- the index to be offsetcodePointOffset
- the offset in code points
NullPointerException
- 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
.
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
.
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
.
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
.
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 tested
true
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
- 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:
'$'
)
'_'
)
isIdentifierIgnorable
returns
true
for the character.
ch
- the character to be tested.
true
if the character may be part of a
Java identifier; false
otherwise.isJavaLetter(char)
,
isJavaIdentifierStart(char)
,
isJavaIdentifierPart(char)
,
isLetter(char)
,
isLetterOrDigit(char)
,
isUnicodeIdentifierPart(char)
,
isIdentifierIgnorable(char)
public static boolean isJavaIdentifierStart(char ch)
A character may start a Java identifier if and only if one of the following conditions is true:
isLetter(ch)
returns true
getType(ch)
returns LETTER_NUMBER
Note: This method cannot handle supplementary characters. To support
all Unicode characters, including supplementary characters, use
the isJavaIdentifierStart(int)
method.
ch
- the character to be tested.
true
if the character may start a Java identifier;
false
otherwise.isJavaIdentifierPart(char)
,
isLetter(char)
,
isUnicodeIdentifierStart(char)
,
SourceVersion.isIdentifier(CharSequence)
public static boolean isJavaIdentifierStart(int codePoint)
A character may start a Java identifier if and only if one of the following conditions is true:
isLetter(codePoint)
returns true
getType(codePoint)
returns LETTER_NUMBER
codePoint
- the character (Unicode code point) to be tested.
true
if the character may start a Java identifier;
false
otherwise.isJavaIdentifierPart(int)
,
isLetter(int)
,
isUnicodeIdentifierStart(int)
,
SourceVersion.isIdentifier(CharSequence)
public static boolean isJavaIdentifierPart(char ch)
A character may be part of a Java identifier if any of the following are true:
'$'
)
'_'
)
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.
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, 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.
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' | '\u0009' |
HORIZONTAL TABULATION |
'\n' | '\u000A' |
NEW LINE |
'\f' | '\u000C' |
FORM FEED |
'\r' | '\u000D' |
CARRIAGE RETURN |
' ' | '\u0020' |
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'
).
'\u0009'
, HORIZONTAL TABULATION.
'\u000A'
, LINE FEED.
'\u000B'
, VERTICAL TABULATION.
'\u000C'
, FORM FEED.
'\u000D'
, CARRIAGE RETURN.
'\u001C'
, FILE SEPARATOR.
'\u001D'
, GROUP SEPARATOR.
'\u001E'
, RECORD SEPARATOR.
'\u001F'
, 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'
).
'\u0009'
, HORIZONTAL TABULATION.
'\u000A'
, LINE FEED.
'\u000B'
, VERTICAL TABULATION.
'\u000C'
, FORM FEED.
'\u000D'
, CARRIAGE RETURN.
'\u001C'
, FILE SEPARATOR.
'\u001D'
, GROUP SEPARATOR.
'\u001E'
, RECORD SEPARATOR.
'\u001F'
, 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_LETTER
public 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_LETTER
public 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_FORMAT
public 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_FORMAT
public 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 requested
true
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 char reverseBytes(char ch)
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