public final class Character extends Object implements Serializable, Comparable<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 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. |
public static final int MIN_RADIX
The minimum radix available for conversion to and from strings. The constant value of this field is the smallest value permitted for the radix argument in radix-conversion methods such as the digit
method, the forDigit
method, and the toString
method of class Integer
.
digit(char, int)
, forDigit(int, int)
, Integer.toString(int, int)
, Integer.valueOf(String)
, Constant Field Valuespublic static final int MAX_RADIX
The maximum radix available for conversion to and from strings. The constant value of this field is the largest value permitted for the radix argument in radix-conversion methods such as the digit
method, the forDigit
method, and the toString
method of class Integer
.
digit(char, int)
, forDigit(int, int)
, Integer.toString(int, int)
, Integer.valueOf(String)
, Constant Field Valuespublic static final char MIN_VALUE
The constant value of this field is the smallest value of type char
, '\u0000'
.
public static final char MAX_VALUE
The constant value of this field is the largest value of type char
, '\uFFFF'
.
public static final Class<Character> TYPE
The Class
instance representing the primitive type char
.
public static final byte UNASSIGNED
General category "Cn" in the Unicode specification.
public static final byte UPPERCASE_LETTER
General category "Lu" in the Unicode specification.
public static final byte LOWERCASE_LETTER
General category "Ll" in the Unicode specification.
public static final byte TITLECASE_LETTER
General category "Lt" in the Unicode specification.
public static final byte MODIFIER_LETTER
General category "Lm" in the Unicode specification.
public static final byte OTHER_LETTER
General category "Lo" in the Unicode specification.
public static final byte NON_SPACING_MARK
General category "Mn" in the Unicode specification.
public static final byte ENCLOSING_MARK
General category "Me" in the Unicode specification.
public static final byte COMBINING_SPACING_MARK
General category "Mc" in the Unicode specification.
public static final byte DECIMAL_DIGIT_NUMBER
General category "Nd" in the Unicode specification.
public static final byte LETTER_NUMBER
General category "Nl" in the Unicode specification.
public static final byte OTHER_NUMBER
General category "No" in the Unicode specification.
public static final byte SPACE_SEPARATOR
General category "Zs" in the Unicode specification.
public static final byte LINE_SEPARATOR
General category "Zl" in the Unicode specification.
public static final byte PARAGRAPH_SEPARATOR
General category "Zp" in the Unicode specification.
public static final byte CONTROL
General category "Cc" in the Unicode specification.
public static final byte FORMAT
General category "Cf" in the Unicode specification.
public static final byte PRIVATE_USE
General category "Co" in the Unicode specification.
public static final byte SURROGATE
General category "Cs" in the Unicode specification.
public static final byte DASH_PUNCTUATION
General category "Pd" in the Unicode specification.
public static final byte START_PUNCTUATION
General category "Ps" in the Unicode specification.
public static final byte END_PUNCTUATION
General category "Pe" in the Unicode specification.
public static final byte CONNECTOR_PUNCTUATION
General category "Pc" in the Unicode specification.
public static final byte OTHER_PUNCTUATION
General category "Po" in the Unicode specification.
public static final byte MATH_SYMBOL
General category "Sm" in the Unicode specification.
public static final byte CURRENCY_SYMBOL
General category "Sc" in the Unicode specification.
public static final byte MODIFIER_SYMBOL
General category "Sk" in the Unicode specification.
public static final byte OTHER_SYMBOL
General category "So" in the Unicode specification.
public static final byte INITIAL_QUOTE_PUNCTUATION
General category "Pi" in the Unicode specification.
public static final byte FINAL_QUOTE_PUNCTUATION
General category "Pf" in the Unicode specification.
public static final byte DIRECTIONALITY_UNDEFINED
Undefined bidirectional character type. Undefined char
values have undefined directionality in the Unicode specification.
public static final byte DIRECTIONALITY_LEFT_TO_RIGHT
Strong bidirectional character type "L" in the Unicode specification.
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT
Strong bidirectional character type "R" in the Unicode specification.
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC
Strong bidirectional character type "AL" in the Unicode specification.
public static final byte DIRECTIONALITY_EUROPEAN_NUMBER
Weak bidirectional character type "EN" in the Unicode specification.
public static final byte DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
Weak bidirectional character type "ES" in the Unicode specification.
public static final byte DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
Weak bidirectional character type "ET" in the Unicode specification.
public static final byte DIRECTIONALITY_ARABIC_NUMBER
Weak bidirectional character type "AN" in the Unicode specification.
public static final byte DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
Weak bidirectional character type "CS" in the Unicode specification.
public static final byte DIRECTIONALITY_NONSPACING_MARK
Weak bidirectional character type "NSM" in the Unicode specification.
public static final byte DIRECTIONALITY_BOUNDARY_NEUTRAL
Weak bidirectional character type "BN" in the Unicode specification.
public static final byte DIRECTIONALITY_PARAGRAPH_SEPARATOR
Neutral bidirectional character type "B" in the Unicode specification.
public static final byte DIRECTIONALITY_SEGMENT_SEPARATOR
Neutral bidirectional character type "S" in the Unicode specification.
public static final byte DIRECTIONALITY_WHITESPACE
Neutral bidirectional character type "WS" in the Unicode specification.
public static final byte DIRECTIONALITY_OTHER_NEUTRALS
Neutral bidirectional character type "ON" in the Unicode specification.
public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING
Strong bidirectional character type "LRE" in the Unicode specification.
public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE
Strong bidirectional character type "LRO" in the Unicode specification.
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING
Strong bidirectional character type "RLE" in the Unicode specification.
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE
Strong bidirectional character type "RLO" in the Unicode specification.
public static final byte DIRECTIONALITY_POP_DIRECTIONAL_FORMAT
Weak bidirectional character type "PDF" in the Unicode specification.
public static final char MIN_HIGH_SURROGATE
The minimum value of a Unicode high-surrogate code unit in the UTF-16 encoding, constant '\uD800'
. A high-surrogate is also known as a leading-surrogate.
public static final char MAX_HIGH_SURROGATE
The maximum value of a Unicode high-surrogate code unit in the UTF-16 encoding, constant '\uDBFF'
. A high-surrogate is also known as a leading-surrogate.
public static final char MIN_LOW_SURROGATE
The minimum value of a Unicode low-surrogate code unit in the UTF-16 encoding, constant '\uDC00'
. A low-surrogate is also known as a trailing-surrogate.
public static final char MAX_LOW_SURROGATE
The maximum value of a Unicode low-surrogate code unit in the UTF-16 encoding, constant '\uDFFF'
. A low-surrogate is also known as a trailing-surrogate.
public static final char MIN_SURROGATE
The minimum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uD800'
.
public static final char MAX_SURROGATE
The maximum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uDFFF'
.
public static final int MIN_SUPPLEMENTARY_CODE_POINT
The minimum value of a Unicode supplementary code point, constant U+10000
.
public static final int MIN_CODE_POINT
The minimum value of a Unicode code point, constant U+0000
.
public static final int MAX_CODE_POINT
The maximum value of a Unicode code point, constant U+10FFFF
.
public static final int SIZE
The number of bits used to represent a char
value in unsigned binary form, constant 16
.
public static final int BYTES
The number of bytes used to represent a char
value in unsigned binary form.
public Character(char value)
Constructs a newly allocated Character
object that represents the specified char
value.
value
- the value to be represented by the Character
object.public static Character valueOf(char c)
Returns a Character
instance representing the specified char
value. If a new Character
instance is not required, this method should generally be used in preference to the constructor 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.Character
instance representing c
.public char charValue()
Returns the value of this Character
object.
char
value represented by this object.public int hashCode()
Returns a hash code for this Character
; equal to the result of invoking charValue()
.
hashCode
in class Object
Character
Object.equals(java.lang.Object)
, System.identityHashCode(java.lang.Object)
public static int hashCode(char value)
Returns a hash code for a char
value; compatible with Character.hashCode()
.
value
- The char
for which to return a hash code.char
value.public boolean equals(Object obj)
Compares this object against the specified object. The result is 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()
, HashMap
public String toString()
Returns a 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)
Returns a 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 convertedchar
public static boolean isValidCodePoint(int codePoint)
Determines whether the specified code point is a valid Unicode code point value.
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)
Determines whether the specified character (Unicode code point) is in the Basic Multilingual Plane (BMP). Such code points can be represented using a single char
.
codePoint
- the character (Unicode code point) to be testedtrue
if the specified code point is between MIN_VALUE
and MAX_VALUE
inclusive; false
otherwise.public static boolean isSupplementaryCodePoint(int codePoint)
Determines whether the specified character (Unicode code point) is in the supplementary character range.
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)
Determines if the given 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)
Determines if the given 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)
Determines if the given 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)
Determines whether the specified pair of 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)
Determines the number of 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)
Converts the specified surrogate pair to its supplementary code point value. This method does not validate the specified surrogate pair. The caller must validate it using isSurrogatePair
if necessary.
high
- the high-surrogate code unitlow
- the low-surrogate code unitpublic static int codePointAt(CharSequence seq, int index)
Returns the code point at the given index of the 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)
Returns the code point at the given index of the 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)
Returns the code point at the given index of the 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)
Returns the code point preceding the given index of the 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)
Returns the code point preceding the given index of the 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)
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. 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)
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. If the specified character is not a supplementary character, an unspecified 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)
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. If the specified character is not a supplementary character, an unspecified 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)
Converts the specified character (Unicode code point) to its UTF-16 representation. If the specified code point is a BMP (Basic Multilingual Plane or Plane 0) value, the same value is stored in 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)
Converts the specified character (Unicode code point) to its UTF-16 representation stored in a 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)
Returns the number of Unicode code points in the text range of the specified char sequence. The text range begins at the specified 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)
Returns the number of Unicode code points in a subarray of the 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
sNullPointerException
- 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)
Returns the index within the given char sequence that is offset from the given 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)
Returns the index within the given 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 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)
Determines if the specified character is a lowercase character.
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)
Determines if the specified character (Unicode code point) is a lowercase character.
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)
Determines if the specified character is an uppercase character.
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)
Determines if the specified character (Unicode code point) is an uppercase character.
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)
Determines if the specified character is a titlecase character.
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)
Determines if the specified character (Unicode code point) is a titlecase character.
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)
Determines if the specified character is a digit.
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)
Determines if the specified character (Unicode code point) is a digit.
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)
Determines if a character is defined in Unicode.
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)
Determines if a character (Unicode code point) is defined in Unicode.
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)
Determines if the specified character is a letter.
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)
Determines if the specified character (Unicode code point) is a letter.
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)
Determines if the specified character is a letter or digit.
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)
Determines if the specified character (Unicode code point) is a letter or digit.
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)
Deprecated. Replaced by isJavaIdentifierStart(char).
Determines if the specified character is permissible as the first character in a Java identifier.
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 '$'
) ch
is a connecting punctuation character (such as '_'
). ch
- the character to be tested.true
if the character may start a Java identifier; false
otherwise.isJavaLetterOrDigit(char)
, isJavaIdentifierStart(char)
, isJavaIdentifierPart(char)
, isLetter(char)
, isLetterOrDigit(char)
, isUnicodeIdentifierStart(char)
@Deprecated public static boolean isJavaLetterOrDigit(char ch)
Deprecated. Replaced by isJavaIdentifierPart(char).
Determines if the specified character may be part of a Java identifier as other than the first character.
A character may be part of a Java identifier if and only if any of the following are true:
'$'
) '_'
) 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)
Determines if the specified character (Unicode code point) is an alphabet.
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)
Determines if the specified character (Unicode code point) is a CJKV (Chinese, Japanese, Korean and Vietnamese) ideograph, as defined by the Unicode Standard.
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)
Determines if the specified character is permissible as the first character in a Java identifier.
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 '$'
) ch
is a connecting punctuation character (such as '_'
). Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierStart(int)
method.
ch
- the character to be tested.true
if the character may start a Java identifier; false
otherwise.isJavaIdentifierPart(char)
, isLetter(char)
, isUnicodeIdentifierStart(char)
, SourceVersion.isIdentifier(CharSequence)
public static boolean isJavaIdentifierStart(int codePoint)
Determines if the character (Unicode code point) is permissible as the first character in a Java identifier.
A character may start a Java identifier if and only if one of the following conditions is true:
isLetter(codePoint)
returns true
getType(codePoint)
returns LETTER_NUMBER
'$'
) '_'
). 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)
Determines if the specified character may be part of a Java identifier as other than the first character.
A character may be part of a Java identifier if any of the following are true:
'$'
) '_'
) isIdentifierIgnorable
returns true
for the character Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierPart(int)
method.
ch
- the character to be tested.true
if the character may be part of a Java identifier; false
otherwise.isIdentifierIgnorable(char)
, isJavaIdentifierStart(char)
, isLetterOrDigit(char)
, isUnicodeIdentifierPart(char)
, SourceVersion.isIdentifier(CharSequence)
public static boolean isJavaIdentifierPart(int codePoint)
Determines if the character (Unicode code point) may be part of a Java identifier as other than the first character.
A character may be part of a Java identifier if any of the following are true:
'$'
) '_'
) 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)
Determines if the specified character is permissible as the first character in a Unicode identifier.
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)
Determines if the specified character (Unicode code point) is permissible as the first character in a Unicode identifier.
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)
Determines if the specified character may be part of a Unicode identifier as other than the first character.
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)
Determines if the specified character (Unicode code point) may be part of a Unicode identifier as other than the first character.
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)
Determines if the specified character should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
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)
Determines if the specified character (Unicode code point) should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
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)
Converts the character argument to lowercase using case mapping information from the UnicodeData file.
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)
Converts the character (Unicode code point) argument to lowercase using case mapping information from the UnicodeData file.
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)
Converts the character argument to uppercase using case mapping information from the UnicodeData file.
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)
Converts the character (Unicode code point) argument to uppercase using case mapping information from the UnicodeData file.
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)
Converts the character argument to titlecase using case mapping information from the UnicodeData file. If a character has no explicit titlecase mapping and is not itself a titlecase char according to UnicodeData, then the uppercase mapping is returned as an equivalent titlecase mapping. If the 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)
Converts the character (Unicode code point) argument to titlecase using case mapping information from the UnicodeData file. If a character has no explicit titlecase mapping and is not itself a titlecase char according to UnicodeData, then the uppercase mapping is returned as an equivalent titlecase mapping. If the character argument is already a titlecase character, the same character value will be returned.
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)
Returns the numeric value of the character 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)
Returns the numeric value of the specified character (Unicode code point) in the specified 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)
Returns the 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)
Returns the 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)
Deprecated. Replaced by isWhitespace(char).
Determines if the specified character is ISO-LATIN-1 white space. This method returns 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)
Determines if the specified character is a Unicode space character. A character is considered to be a space character if and only if it is specified to be a space character by the Unicode Standard. This method returns true if the character's general category type is any of the following:
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)
Determines if the specified character (Unicode code point) is a Unicode space character. A character is considered to be a space character if and only if it is specified to be a space character by the Unicode Standard. This method returns true if the character's general category type is any of the following:
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)
Determines if the specified character is white space according to Java. A character is a Java whitespace character if and only if it satisfies one of the following criteria:
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)
Determines if the specified character (Unicode code point) is white space according to Java. A character is a Java whitespace character if and only if it satisfies one of the following criteria:
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)
Determines if the specified character is an ISO control character. A character is considered to be an ISO control character if its code is in the range '\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)
Determines if the referenced character (Unicode code point) is an ISO control character. A character is considered to be an ISO control character if its code is in the range '\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)
Returns a value indicating a character's general category.
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)
Returns a value indicating a character's general category.
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)
Determines the character representation for a specific digit in the specified radix. If the value of 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)
Returns the Unicode directionality property for the given character. Character directionality is used to calculate the visual ordering of text. The directionality value of undefined 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)
Returns the Unicode directionality property for the given character (Unicode code point). Character directionality is used to calculate the visual ordering of text. The directionality value of undefined character is 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)
Determines whether the character is mirrored according to the Unicode specification. Mirrored characters should have their glyphs horizontally mirrored when displayed in text that is right-to-left. For example, '\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)
Determines whether the specified character (Unicode code point) is mirrored according to the Unicode specification. Mirrored characters should have their glyphs horizontally mirrored when displayed in text that is right-to-left. For example, '\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)
Compares two 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)
Compares two 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 > y
public static char reverseBytes(char ch)
Returns the value obtained by reversing the order of the bytes in the specified char
value.
ch
- The char
of which to reverse the byte order.char
value.public static String getName(int codePoint)
Returns the Unicode name of the specified character 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.
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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