Serializable, Comparable<Character>, Constable
The
Character
class wraps a value of the primitive type
char
in an object. An object of class
Character
contains a single field whose type is
char
.
In addition, this class provides a large number of static methods for determining a character's category (lowercase letter, digit, etc.) and for converting characters from uppercase to lowercase and vice versa.
Unicode ConformanceThe fields and methods of class Character are defined in terms of character information from the Unicode Standard, specifically the UnicodeData file that is part of the Unicode Character Database. This file specifies properties including name and category for every assigned Unicode code point or character range. The file is available from the Unicode Consortium at http://www.unicode.org.
Character information is based on the Unicode Standard, version 15.0.
The Java platform has supported different versions of the Unicode Standard over time. Upgrades to newer versions of the Unicode Standard occurred in the following Java releases, each indicating the new version:
Shows Java releases and supported Unicode versions Java release Unicode version Java SE 20 Unicode 15.0 Java SE 19 Unicode 14.0 Java SE 15 Unicode 13.0 Java SE 13 Unicode 12.1 Java SE 12 Unicode 11.0 Java SE 11 Unicode 10.0 Java SE 9 Unicode 8.0 Java SE 8 Unicode 6.2 Java SE 7 Unicode 6.0 Java SE 5.0 Unicode 4.0 Java SE 1.4 Unicode 3.0 JDK 1.1 Unicode 2.0 JDK 1.0.2 Unicode 1.1.5Variations from these base Unicode versions, such as recognized appendixes, are documented elsewhere.
Unicode Character RepresentationsThe 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.
This is a value-based class; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.
Nested Classes
static class
Instances of this class represent particular subsets of the Unicode character set.
static final class
A family of character subsets representing the character blocks in the Unicode specification.
static enum
Fields
static final int
The number of bytes used to represent a char value in unsigned binary form.
static final byte
General category "Mc" in the Unicode specification.
static final byte
General category "Pc" in the Unicode specification.
static final byte
General category "Cc" in the Unicode specification.
static final byte
General category "Sc" in the Unicode specification.
static final byte
General category "Pd" in the Unicode specification.
static final byte
General category "Nd" in the Unicode specification.
static final byte
Weak bidirectional character type "AN" in the Unicode specification.
static final byte
Weak bidirectional character type "BN" in the Unicode specification.
static final byte
Weak bidirectional character type "CS" in the Unicode specification.
static final byte
Weak bidirectional character type "EN" in the Unicode specification.
static final byte
Weak bidirectional character type "ES" in the Unicode specification.
static final byte
Weak bidirectional character type "ET" in the Unicode specification.
static final byte
Weak bidirectional character type "FSI" in the Unicode specification.
static final byte
Strong bidirectional character type "L" in the Unicode specification.
static final byte
Strong bidirectional character type "LRE" in the Unicode specification.
static final byte
Weak bidirectional character type "LRI" in the Unicode specification.
static final byte
Strong bidirectional character type "LRO" in the Unicode specification.
static final byte
Weak bidirectional character type "NSM" in the Unicode specification.
static final byte
Neutral bidirectional character type "ON" in the Unicode specification.
static final byte
Neutral bidirectional character type "B" in the Unicode specification.
static final byte
Weak bidirectional character type "PDF" in the Unicode specification.
static final byte
Weak bidirectional character type "PDI" in the Unicode specification.
static final byte
Strong bidirectional character type "R" in the Unicode specification.
static final byte
Strong bidirectional character type "AL" in the Unicode specification.
static final byte
Strong bidirectional character type "RLE" in the Unicode specification.
static final byte
Weak bidirectional character type "RLI" in the Unicode specification.
static final byte
Strong bidirectional character type "RLO" in the Unicode specification.
static final byte
Neutral bidirectional character type "S" in the Unicode specification.
static final byte
Undefined bidirectional character type.
static final byte
Neutral bidirectional character type "WS" in the Unicode specification.
static final byte
General category "Me" in the Unicode specification.
static final byte
General category "Pe" in the Unicode specification.
static final byte
General category "Pf" in the Unicode specification.
static final byte
General category "Cf" in the Unicode specification.
static final byte
General category "Pi" in the Unicode specification.
static final byte
General category "Nl" in the Unicode specification.
static final byte
General category "Zl" in the Unicode specification.
static final byte
General category "Ll" in the Unicode specification.
static final byte
General category "Sm" in the Unicode specification.
static final int
static final char
static final char
static final int
The maximum radix available for conversion to and from strings.
static final char
The maximum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uDFFF'.
static final char
The constant value of this field is the largest value of type char, '\uFFFF'.
static final int
static final char
static final char
static final int
The minimum radix available for conversion to and from strings.
static final int
static final char
The minimum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uD800'.
static final char
The constant value of this field is the smallest value of type char, '\u0000'.
static final byte
General category "Lm" in the Unicode specification.
static final byte
General category "Sk" in the Unicode specification.
static final byte
General category "Mn" in the Unicode specification.
static final byte
General category "Lo" in the Unicode specification.
static final byte
General category "No" in the Unicode specification.
static final byte
General category "Po" in the Unicode specification.
static final byte
General category "So" in the Unicode specification.
static final byte
General category "Zp" in the Unicode specification.
static final byte
General category "Co" in the Unicode specification.
static final int
The number of bits used to represent a char value in unsigned binary form, constant 16.
static final byte
General category "Zs" in the Unicode specification.
static final byte
General category "Ps" in the Unicode specification.
static final byte
General category "Cs" in the Unicode specification.
static final byte
General category "Lt" in the Unicode specification.
The Class instance representing the primitive type char.
static final byte
General category "Cn" in the Unicode specification.
static final byte
General category "Lu" in the Unicode specification.
Constructors
Deprecated, for removal: This API element is subject to removal in a future version.static int
Determines the number of char values needed to represent the specified character (Unicode code point).
char
Returns the value of this Character object.
static int
Returns the code point at the given index of the char array.
static int
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
Returns the code point at the given index of the CharSequence.
static int
Returns the code point preceding the given index of the char array.
static int
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
Returns the code point preceding the given index of the CharSequence.
static int
Returns the number of Unicode code points in a subarray of the char array argument.
static int
Returns the number of Unicode code points in the text range of the specified char sequence.
static int
Returns the code point value of the Unicode character specified by the given character name.
static int
Compares two char values numerically.
int
Compares two Character objects numerically.
Returns an
Optional
containing the nominal descriptor for this instance.
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
Compares this object against the specified object.
static char
Determines the character representation for a specific digit in the specified radix.
static byte
Returns the Unicode directionality property for the given character.
static byte
Returns the Unicode directionality property for the given character (Unicode code point).
Returns the name of the specified character
codePoint
, or null if the code point is
unassigned
.
static int
Returns the int value that the specified Unicode character represents.
static int
Returns the int value that the specified character (Unicode code point) represents.
static int
Returns a value indicating a character's general category.
static int
Returns a value indicating a character's general category.
int
Returns a hash code for this Character; equal to the result of invoking charValue().
static int
Returns a hash code for a char value; compatible with Character.hashCode().
static char
static boolean
Determines if the specified character (Unicode code point) is alphabetic.
static boolean
static boolean
Determines if a character is defined in Unicode.
static boolean
Determines if a character (Unicode code point) is defined in Unicode.
static boolean
Determines if the specified character is a digit.
static boolean
Determines if the specified character (Unicode code point) is a digit.
static boolean
static boolean
Determines if the specified character should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
static boolean
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
Determines if the specified character (Unicode code point) is a CJKV (Chinese, Japanese, Korean and Vietnamese) ideograph, as defined by the Unicode Standard.
static boolean
Determines if the specified character is an ISO control character.
static boolean
Determines if the referenced character (Unicode code point) is an ISO control character.
static boolean
Determines if the specified character may be part of a Java identifier as other than the first character.
static boolean
Determines if the character (Unicode code point) may be part of a Java identifier as other than the first character.
static boolean
Determines if the specified character is permissible as the first character in a Java identifier.
static boolean
Determines if the character (Unicode code point) is permissible as the first character in a Java identifier.
static boolean
static boolean
static boolean
Determines if the specified character is a letter.
static boolean
Determines if the specified character (Unicode code point) is a letter.
static boolean
Determines if the specified character is a letter or digit.
static boolean
Determines if the specified character (Unicode code point) is a letter or digit.
static boolean
Determines if the specified character is a lowercase character.
static boolean
Determines if the specified character (Unicode code point) is a lowercase character.
static boolean
static boolean
Determines whether the character is mirrored according to the Unicode specification.
static boolean
Determines whether the specified character (Unicode code point) is mirrored according to the Unicode specification.
static boolean
static boolean
Determines if the specified character is a Unicode space character.
static boolean
Determines if the specified character (Unicode code point) is a Unicode space character.
static boolean
static boolean
Determines if the given char value is a Unicode surrogate code unit.
static boolean
static boolean
Determines if the specified character is a titlecase character.
static boolean
Determines if the specified character (Unicode code point) is a titlecase character.
static boolean
Determines if the specified character may be part of a Unicode identifier as other than the first character.
static boolean
Determines if the specified character (Unicode code point) may be part of a Unicode identifier as other than the first character.
static boolean
Determines if the specified character is permissible as the first character in a Unicode identifier.
static boolean
Determines if the specified character (Unicode code point) is permissible as the first character in a Unicode identifier.
static boolean
Determines if the specified character is an uppercase character.
static boolean
Determines if the specified character (Unicode code point) is an uppercase character.
static boolean
static boolean
Determines if the specified character is white space according to Java.
static boolean
Determines if the specified character (Unicode code point) is white space according to Java.
static char
static int
Returns the index within the given char subarray that is offset from the given index by codePointOffset code points.
static int
Returns the index within the given char sequence that is offset from the given index by codePointOffset code points.
static char
Returns the value obtained by reversing the order of the bytes in the specified char value.
static char[]
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
Converts the specified surrogate pair to its supplementary code point value.
static char
Converts the character argument to lowercase using case mapping information from the UnicodeData file.
static int
Converts the character (Unicode code point) argument to lowercase using case mapping information from the UnicodeData file.
Returns a String object representing this Character's value.
Returns a String object representing the specified char.
Returns a String object representing the specified character (Unicode code point).
static char
Converts the character argument to titlecase using case mapping information from the UnicodeData file.
static int
Converts the character (Unicode code point) argument to titlecase using case mapping information from the UnicodeData file.
static char
Converts the character argument to uppercase using case mapping information from the UnicodeData file.
static int
Converts the character (Unicode code point) argument to uppercase using case mapping information from the UnicodeData file.
Returns a Character instance representing the specified char value.
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.
public 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.
public 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'.
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 byte DIRECTIONALITY_LEFT_TO_RIGHT_ISOLATE
Weak bidirectional character type "LRI" in the Unicode specification.
public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_ISOLATE
Weak bidirectional character type "RLI" in the Unicode specification.
public static final byte DIRECTIONALITY_FIRST_STRONG_ISOLATE
Weak bidirectional character type "FSI" in the Unicode specification.
public static final byte DIRECTIONALITY_POP_DIRECTIONAL_ISOLATE
Weak bidirectional character type "PDI" in the Unicode specification.
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
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
public static final int MIN_CODE_POINT
public static final int MAX_CODE_POINT
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.
Constructs a newly allocated Character object that represents the specified char value.
value - the value to be represented by the Character object.
Returns an
Optional
containing the nominal descriptor for this instance.
describeConstable in interface Constable
Optional describing the Character instance
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().
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.
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.
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.
Returns a String object representing the specified char. The result is a string of length 1 consisting solely of the specified char.
toString(int) method.
c - the char to be converted
char
Returns a String object representing the specified character (Unicode code point). The result is a string of length 1 or 2, consisting solely of the specified codePoint.
codePoint - the codePoint to be converted
codePoint
IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
public static boolean isValidCodePoint(int codePoint)
codePoint - the Unicode code point to be tested
true 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
.
public static boolean isSupplementaryCodePoint(int codePoint)
codePoint - the character (Unicode code point) to be tested
true if the specified code point is between MIN_SUPPLEMENTARY_CODE_POINT and MAX_CODE_POINT inclusive; false otherwise.
public static boolean isHighSurrogate(char ch)
ch - the char value to be tested.
true if the char value is between MIN_HIGH_SURROGATE and MAX_HIGH_SURROGATE inclusive; false otherwise.
public static boolean isLowSurrogate(char ch)
ch - the char value to be tested.
true if the char value is between MIN_LOW_SURROGATE and MAX_LOW_SURROGATE inclusive; false otherwise.
public static boolean isSurrogate(char ch)
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 tested
low - 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)
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.
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 unit
low - the low-surrogate code unit
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 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)
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 array
index - 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)
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 array
index - the index to the char values (Unicode code units) in the char array to be converted
limit - 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.
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 instance
index - 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)
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 array
index - 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 array
public 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 array
index - the index following the code point that should be returned
start - 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 char highSurrogate(int codePoint)
codePoint - a supplementary character (Unicode code point)
public static char lowSurrogate(int codePoint)
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 point
char array having codePoint's UTF-16 representation.
IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
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 chars) of the text range is endIndex-beginIndex. Unpaired surrogates within the text range count as one code point each.
seq - the char sequence
beginIndex - 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 chars. Unpaired surrogates within the subarray count as one code point each.
a - the char array
offset - the index of the first char in the given char array
count - the length of the subarray in chars
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.
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 sequence
index - the index to be offset
codePointOffset - the offset in code points
NullPointerException - if seq is null.
IndexOutOfBoundsException - if index is negative or larger than 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 array
start - the index of the first char of the subarray
count - the length of the subarray in chars
index - the index to be offset
codePointOffset - 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)
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.
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.
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.
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.
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 CARONLATIN CAPITAL LETTER L WITH SMALL LETTER JLATIN CAPITAL LETTER N WITH SMALL LETTER JLATIN CAPITAL LETTER D WITH SMALL LETTER ZMany 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.
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 CARONLATIN CAPITAL LETTER L WITH SMALL LETTER JLATIN CAPITAL LETTER N WITH SMALL LETTER JLATIN CAPITAL LETTER D WITH SMALL LETTER ZMany other Unicode characters are titlecase too.
codePoint - the character (Unicode code point) to be tested.
true if the character is titlecase; false otherwise.
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 digitsMany other character ranges contain digits as well.
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.
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 digitsMany other character ranges contain digits as well.
codePoint - the character (Unicode code point) to be tested.
true if the character is a digit; false otherwise.
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 tested
true if the character has a defined meaning in Unicode; false otherwise.
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.
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_LETTERLOWERCASE_LETTERTITLECASE_LETTERMODIFIER_LETTEROTHER_LETTERNot all letters have case. Many characters are letters but are neither uppercase nor lowercase nor titlecase.
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.
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_LETTERLOWERCASE_LETTERTITLECASE_LETTERMODIFIER_LETTEROTHER_LETTERNot all letters have case. Many characters are letters but are neither uppercase nor lowercase nor titlecase.
codePoint - the character (Unicode code point) to be tested.
true if the character is a letter; false otherwise.
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.
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.
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 truegetType(ch) returns LETTER_NUMBERch is a currency symbol (such as '$')ch is a connecting punctuation character (such as '_').ch - the character to be tested.
true if the character may start a Java identifier; false otherwise.
Determines if the specified character may be part of a Java identifier as other than the first character.
A character may be part of a Java identifier if and only if one of the following conditions is true:
'$')'_')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.
public static boolean isAlphabetic(int codePoint)
Determines if the specified character (Unicode code point) is alphabetic.
A character is considered to be alphabetic if its general category type, provided by getType(codePoint), is any of the following:
UPPERCASE_LETTERLOWERCASE_LETTERTITLECASE_LETTERMODIFIER_LETTEROTHER_LETTERLETTER_NUMBERor it has contributory property Other_Alphabetic as defined by the Unicode Standard.
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 truegetType(ch) returns LETTER_NUMBERch is a currency symbol (such as '$')ch is a connecting punctuation character (such as '_').Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierStart(int) method.
ch - the character to be tested.
true if the character may start a Java identifier; false otherwise.
public static boolean isJavaIdentifierStart(int codePoint)
Determines if the character (Unicode code point) is permissible as the first character in a Java identifier.
A character may start a Java identifier if and only if one of the following conditions is true:
isLetter(codePoint) returns truegetType(codePoint) returns LETTER_NUMBER'$')'_').codePoint - the character (Unicode code point) to be tested.
true if the character may start a Java identifier; false otherwise.
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 conditions are true:
'$')'_')isIdentifierIgnorable returns true for the characterNote: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierPart(int) method.
ch - the character to be tested.
true if the character may be part of a Java identifier; false otherwise.
public static boolean isJavaIdentifierPart(int codePoint)
Determines if the character (Unicode code point) may be part of a Java identifier as other than the first character.
A character may be part of a Java identifier if any of the following conditions are true:
'$')'_')isIdentifierIgnorable(codePoint) returns true for the code pointcodePoint - the character (Unicode code point) to be tested.
true if the character may be part of a Java identifier; false otherwise.
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 truegetType(ch) returns LETTER_NUMBER.Other_ID_Start character.This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31:
Start := ID_Start + 'VERTICAL TILDE' (U+2E2F)
'VERTICAL TILDE'
is added to
Start
for backward compatibility.
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.
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 truegetType(codePoint) returns LETTER_NUMBER.Other_ID_Start character.This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31:
Start := ID_Start + 'VERTICAL TILDE' (U+2E2F)
'VERTICAL TILDE'
is added to
Start
for backward compatibility.
codePoint - the character (Unicode code point) to be tested.
true if the character may start a Unicode identifier; false otherwise.
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.Other_ID_Start character.Other_ID_Continue character.This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31:
Continue := Start + ID_Continue + ignorable Medial := empty ignorable := isIdentifierIgnorable(char) returns true for the character
ignorable
is added to
Continue
for backward compatibility.
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.
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.Other_ID_Start character.Other_ID_Continue character.This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31:
Continue := Start + ID_Continue + ignorable Medial := empty ignorable := isIdentifierIgnorable(int) returns true for the character
ignorable
is added to
Continue
for backward compatibility.
codePoint - the character (Unicode code point) to be tested.
true if the character may be part of a Unicode identifier; false otherwise.
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 valueNote: 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.
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 valuecodePoint - 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.
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.
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.
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.
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.
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.
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.
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.
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.
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 but the value can not be represented as a nonnegative int value; -1 if the character has no numeric value.
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 but the value can not be represented as a nonnegative int value; -1 if the character has no numeric value.
Determines if the specified character is ISO-LATIN-1 white space. This method returns
true
for the following five characters only:
truechars Character Code Name'\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.
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_SEPARATORLINE_SEPARATORPARAGRAPH_SEPARATORNote: 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.
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.
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.
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.
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.
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.
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_MARKCONNECTOR_PUNCTUATIONCONTROLCURRENCY_SYMBOLDASH_PUNCTUATIONDECIMAL_DIGIT_NUMBERENCLOSING_MARKEND_PUNCTUATIONFINAL_QUOTE_PUNCTUATIONFORMATINITIAL_QUOTE_PUNCTUATIONLETTER_NUMBERLINE_SEPARATORLOWERCASE_LETTERMATH_SYMBOLMODIFIER_LETTERMODIFIER_SYMBOLNON_SPACING_MARKOTHER_LETTEROTHER_NUMBEROTHER_PUNCTUATIONOTHER_SYMBOLPARAGRAPH_SEPARATORPRIVATE_USESPACE_SEPARATORSTART_PUNCTUATIONSURROGATETITLECASE_LETTERUNASSIGNEDUPPERCASE_LETTERpublic 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_MARKCONNECTOR_PUNCTUATIONCONTROLCURRENCY_SYMBOLDASH_PUNCTUATIONDECIMAL_DIGIT_NUMBERENCLOSING_MARKEND_PUNCTUATIONFINAL_QUOTE_PUNCTUATIONFORMATINITIAL_QUOTE_PUNCTUATIONLETTER_NUMBERLINE_SEPARATORLOWERCASE_LETTERMATH_SYMBOLMODIFIER_LETTERMODIFIER_SYMBOLNON_SPACING_MARKOTHER_LETTEROTHER_NUMBEROTHER_PUNCTUATIONOTHER_SYMBOLPARAGRAPH_SEPARATORPRIVATE_USESPACE_SEPARATORSTART_PUNCTUATIONSURROGATETITLECASE_LETTERUNASSIGNEDUPPERCASE_LETTERpublic 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.
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_UNDEFINEDDIRECTIONALITY_LEFT_TO_RIGHTDIRECTIONALITY_RIGHT_TO_LEFTDIRECTIONALITY_RIGHT_TO_LEFT_ARABICDIRECTIONALITY_EUROPEAN_NUMBERDIRECTIONALITY_EUROPEAN_NUMBER_SEPARATORDIRECTIONALITY_EUROPEAN_NUMBER_TERMINATORDIRECTIONALITY_ARABIC_NUMBERDIRECTIONALITY_COMMON_NUMBER_SEPARATORDIRECTIONALITY_NONSPACING_MARKDIRECTIONALITY_BOUNDARY_NEUTRALDIRECTIONALITY_PARAGRAPH_SEPARATORDIRECTIONALITY_SEGMENT_SEPARATORDIRECTIONALITY_WHITESPACEDIRECTIONALITY_OTHER_NEUTRALSDIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDINGDIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDEDIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDINGDIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDEDIRECTIONALITY_POP_DIRECTIONAL_FORMATDIRECTIONALITY_LEFT_TO_RIGHT_ISOLATEDIRECTIONALITY_RIGHT_TO_LEFT_ISOLATEDIRECTIONALITY_FIRST_STRONG_ISOLATEDIRECTIONALITY_POP_DIRECTIONAL_ISOLATEpublic 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_UNDEFINEDDIRECTIONALITY_LEFT_TO_RIGHTDIRECTIONALITY_RIGHT_TO_LEFTDIRECTIONALITY_RIGHT_TO_LEFT_ARABICDIRECTIONALITY_EUROPEAN_NUMBERDIRECTIONALITY_EUROPEAN_NUMBER_SEPARATORDIRECTIONALITY_EUROPEAN_NUMBER_TERMINATORDIRECTIONALITY_ARABIC_NUMBERDIRECTIONALITY_COMMON_NUMBER_SEPARATORDIRECTIONALITY_NONSPACING_MARKDIRECTIONALITY_BOUNDARY_NEUTRALDIRECTIONALITY_PARAGRAPH_SEPARATORDIRECTIONALITY_SEGMENT_SEPARATORDIRECTIONALITY_WHITESPACEDIRECTIONALITY_OTHER_NEUTRALSDIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDINGDIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDEDIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDINGDIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDEDIRECTIONALITY_POP_DIRECTIONAL_FORMATDIRECTIONALITY_LEFT_TO_RIGHT_ISOLATEDIRECTIONALITY_RIGHT_TO_LEFT_ISOLATEDIRECTIONALITY_FIRST_STRONG_ISOLATEDIRECTIONALITY_POP_DIRECTIONAL_ISOLATEpublic 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 requested
true 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.
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 compare
y - the second char to compare
0 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.
Returns the name of the specified character
codePoint
, or null if the code point is
unassigned
.
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 the expression:
Character.UnicodeBlock.of(codePoint).toString().replace('_', ' ') + " " + Integer.toHexString(codePoint).toUpperCase(Locale.ROOT);
For the
codePoint
s in the
UnicodeDatafile, the name returned by this method follows the naming scheme in the "Unicode Name Property" section of the Unicode Standard. For other code points, such as Hangul/Ideographs, The name generation rule above differs from the one defined in the Unicode Standard.
codePoint - the character (Unicode code point)
IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
Returns the code point value of the Unicode character specified by the given character name.
If a character is not assigned a name by the UnicodeData file (part of the Unicode Character Database maintained by the Unicode Consortium), its name is defined as the result of the expression:
Character.UnicodeBlock.of(codePoint).toString().replace('_', ' ') + " " + Integer.toHexString(codePoint).toUpperCase(Locale.ROOT);
The name matching is case insensitive, with any leading and trailing whitespace character removed. For the code points in the UnicodeData file, this method recognizes the name which conforms to the name defined in the "Unicode Name Property" section in the Unicode Standard. For other code points, this method recognizes the name generated with getName(int) method.
name - the character name
IllegalArgumentException - if the specified name is not a valid character name.
NullPointerException - if name is null
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