Character

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java.lang
Class Character

java.lang.Object   
  java.lang.Character

All Implemented Interfaces:: Serializable , Comparable <Character >

public final class Character
extends Object
implements Serializable , Comparable <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 4.0.

The methods and data of class Character are defined by the information in the UnicodeData file that is part of the Unicode Character Database maintained by the Unicode Consortium. This file specifies various properties including name and general category for every defined Unicode code point or character range.

The file and its description are available from the Unicode Consortium at:

http://www.unicode.org

Unicode Character Representations

The char data type (and therefore the value that a Character object encapsulates) are based on the original Unicode specification, which defined characters as fixed-width 16-bit entities. The Unicode standard has since been changed to allow for characters whose representation requires more than 16 bits. The range of legal code points is now U+0000 to U+10FFFF, known as Unicode scalar value. (Refer to the definition of the U+n notation in the Unicode standard.)

The set of characters from U+0000 to U+FFFF is sometimes referred to as the Basic Multilingual Plane (BMP). Characters whose code points are greater than U+FFFF are called supplementary characters. The Java 2 platform uses the UTF-16 representation in char arrays and in the String and StringBuffer classes. In this representation, supplementary characters are represented as a pair of char values, the first from the high-surrogates range, (\uD800-\uDBFF), the second from the low-surrogates range (\uDC00-\uDFFF).

A char value, therefore, represents Basic Multilingual Plane (BMP) code points, including the surrogate code points, or code units of the UTF-16 encoding. An int value represents all Unicode code points, including supplementary code points. The lower (least significant) 21 bits of int are used to represent Unicode code points and the upper (most significant) 11 bits must be zero. Unless otherwise specified, the behavior with respect to supplementary characters and surrogate char values is as follows:

The methods that only accept a 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.
The methods that accept an 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 J2SE 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.

Since:: 1.0
See Also:: Serialized Form

Nested Class Summary
`static class`	`Character.Subset` Instances of this class represent particular subsets of the Unicode character set.
`static class`	`Character.UnicodeBlock` A family of character subsets representing the character blocks in the Unicode specification.

Field Summary
`static byte`	`COMBINING_SPACING_MARK` General category "Mc" in the Unicode specification.
`static byte`	`CONNECTOR_PUNCTUATION` General category "Pc" in the Unicode specification.
`static byte`	`CONTROL` General category "Cc" in the Unicode specification.
`static byte`	`CURRENCY_SYMBOL` General category "Sc" in the Unicode specification.
`static byte`	`DASH_PUNCTUATION` General category "Pd" in the Unicode specification.
`static byte`	`DECIMAL_DIGIT_NUMBER` General category "Nd" in the Unicode specification.
`static byte`	`DIRECTIONALITY_ARABIC_NUMBER` Weak bidirectional character type "AN" in the Unicode specification.
`static byte`	`DIRECTIONALITY_BOUNDARY_NEUTRAL` Weak bidirectional character type "BN" in the Unicode specification.
`static byte`	`DIRECTIONALITY_COMMON_NUMBER_SEPARATOR` Weak bidirectional character type "CS" in the Unicode specification.
`static byte`	`DIRECTIONALITY_EUROPEAN_NUMBER` Weak bidirectional character type "EN" in the Unicode specification.
`static byte`	`DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR` Weak bidirectional character type "ES" in the Unicode specification.
`static byte`	`DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR` Weak bidirectional character type "ET" in the Unicode specification.
`static byte`	`DIRECTIONALITY_LEFT_TO_RIGHT` Strong bidirectional character type "L" in the Unicode specification.
`static byte`	`DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING` Strong bidirectional character type "LRE" in the Unicode specification.
`static byte`	`DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE` Strong bidirectional character type "LRO" in the Unicode specification.
`static byte`	`DIRECTIONALITY_NONSPACING_MARK` Weak bidirectional character type "NSM" in the Unicode specification.
`static byte`	`DIRECTIONALITY_OTHER_NEUTRALS` Neutral bidirectional character type "ON" in the Unicode specification.
`static byte`	`DIRECTIONALITY_PARAGRAPH_SEPARATOR` Neutral bidirectional character type "B" in the Unicode specification.
`static byte`	`DIRECTIONALITY_POP_DIRECTIONAL_FORMAT` Weak bidirectional character type "PDF" in the Unicode specification.
`static byte`	`DIRECTIONALITY_RIGHT_TO_LEFT` Strong bidirectional character type "R" in the Unicode specification.
`static byte`	`DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC` Strong bidirectional character type "AL" in the Unicode specification.
`static byte`	`DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING` Strong bidirectional character type "RLE" in the Unicode specification.
`static byte`	`DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE` Strong bidirectional character type "RLO" in the Unicode specification.
`static byte`	`DIRECTIONALITY_SEGMENT_SEPARATOR` Neutral bidirectional character type "S" in the Unicode specification.
`static byte`	`DIRECTIONALITY_UNDEFINED` Undefined bidirectional character type.
`static byte`	`DIRECTIONALITY_WHITESPACE` Neutral bidirectional character type "WS" in the Unicode specification.
`static byte`	`ENCLOSING_MARK` General category "Me" in the Unicode specification.
`static byte`	`END_PUNCTUATION` General category "Pe" in the Unicode specification.
`static byte`	`FINAL_QUOTE_PUNCTUATION` General category "Pf" in the Unicode specification.
`static byte`	`FORMAT` General category "Cf" in the Unicode specification.
`static byte`	`INITIAL_QUOTE_PUNCTUATION` General category "Pi" in the Unicode specification.
`static byte`	`LETTER_NUMBER` General category "Nl" in the Unicode specification.
`static byte`	`LINE_SEPARATOR` General category "Zl" in the Unicode specification.
`static byte`	`LOWERCASE_LETTER` General category "Ll" in the Unicode specification.
`static byte`	`MATH_SYMBOL` General category "Sm" in the Unicode specification.
`static int`	`MAX_CODE_POINT` The maximum value of a Unicode code point.
`static char`	`MAX_HIGH_SURROGATE` The maximum value of a Unicode high-surrogate code unit in the UTF-16 encoding.
`static char`	`MAX_LOW_SURROGATE` The maximum value of a Unicode low-surrogate code unit in the UTF-16 encoding.
`static int`	`MAX_RADIX` The maximum radix available for conversion to and from strings.
`static char`	`MAX_SURROGATE` The maximum value of a Unicode surrogate code unit in the UTF-16 encoding.
`static char`	`MAX_VALUE` The constant value of this field is the largest value of type `char`, `'\uFFFF'`.
`static int`	`MIN_CODE_POINT` The minimum value of a Unicode code point.
`static char`	`MIN_HIGH_SURROGATE` The minimum value of a Unicode high-surrogate code unit in the UTF-16 encoding.
`static char`	`MIN_LOW_SURROGATE` The minimum value of a Unicode low-surrogate code unit in the UTF-16 encoding.
`static int`	`MIN_RADIX` The minimum radix available for conversion to and from strings.
`static int`	`MIN_SUPPLEMENTARY_CODE_POINT` The minimum value of a supplementary code point.
`static char`	`MIN_SURROGATE` The minimum value of a Unicode surrogate code unit in the UTF-16 encoding.
`static char`	`MIN_VALUE` The constant value of this field is the smallest value of type `char`, `'\u0000'`.
`static byte`	`MODIFIER_LETTER` General category "Lm" in the Unicode specification.
`static byte`	`MODIFIER_SYMBOL` General category "Sk" in the Unicode specification.
`static byte`	`NON_SPACING_MARK` General category "Mn" in the Unicode specification.
`static byte`	`OTHER_LETTER` General category "Lo" in the Unicode specification.
`static byte`	`OTHER_NUMBER` General category "No" in the Unicode specification.
`static byte`	`OTHER_PUNCTUATION` General category "Po" in the Unicode specification.
`static byte`	`OTHER_SYMBOL` General category "So" in the Unicode specification.
`static byte`	`PARAGRAPH_SEPARATOR` General category "Zp" in the Unicode specification.
`static byte`	`PRIVATE_USE` General category "Co" in the Unicode specification.
`static int`	`SIZE` The number of bits used to represent a `char` value in unsigned binary form.
`static byte`	`SPACE_SEPARATOR` General category "Zs" in the Unicode specification.
`static byte`	`START_PUNCTUATION` General category "Ps" in the Unicode specification.
`static byte`	`SURROGATE` General category "Cs" in the Unicode specification.
`static byte`	`TITLECASE_LETTER` General category "Lt" in the Unicode specification.
`static Class <Character >`	`TYPE` The `Class` instance representing the primitive type `char`.
`static byte`	`UNASSIGNED` General category "Cn" in the Unicode specification.
`static byte`	`UPPERCASE_LETTER` General category "Lu" in the Unicode specification.

Constructor Summary
`Character (char value)` Constructs a newly allocated `Character` object that represents the specified `char` value.

Method Summary
`static int`	`charCount (int codePoint)` Determines the number of `char` values needed to represent the specified character (Unicode code point).
`char`	`charValue ()` Returns the value of this `Character` object.
`static int`	`codePointAt (char[] a, int index)` Returns the code point at the given index of the `char` array.
`static int`	`codePointAt (char[] a, int index, int limit)` Returns the code point at the given index of the `char` array, where only array elements with `index` less than `limit` can be used.
`static int`	`codePointAt (CharSequence seq, int index)` Returns the code point at the given index of the `CharSequence`.
`static int`	`codePointBefore (char[] a, int index)` Returns the code point preceding the given index of the `char` array.
`static int`	`codePointBefore (char[] a, int index, int start)` Returns the code point preceding the given index of the `char` array, where only array elements with `index` greater than or equal to `start` can be used.
`static int`	`codePointBefore (CharSequence seq, int index)` Returns the code point preceding the given index of the `CharSequence`.
`static int`	`codePointCount (char[] a, int offset, int count)` Returns the number of Unicode code points in a subarray of the `char` array argument.
`static int`	`codePointCount (CharSequence seq, int beginIndex, int endIndex)` Returns the number of Unicode code points in the text range of the specified char sequence.
`int`	`compareTo (Character anotherCharacter)` Compares two `Character` objects numerically.
`static int`	`digit (char ch, int radix)` Returns the numeric value of the character `ch` in the specified radix.
`static int`	`digit (int codePoint, int radix)` Returns the numeric value of the specified character (Unicode code point) in the specified radix.
`boolean`	`equals (Object obj)` Compares this object against the specified object.
`static char`	`forDigit (int digit, int radix)` Determines the character representation for a specific digit in the specified radix.
`static byte`	`getDirectionality (char ch)` Returns the Unicode directionality property for the given character.
`static byte`	`getDirectionality (int codePoint)` Returns the Unicode directionality property for the given character (Unicode code point).
`static int`	`getNumericValue (char ch)` Returns the `int` value that the specified Unicode character represents.
`static int`	`getNumericValue (int codePoint)` Returns the `int` value that the specified character (Unicode code point) represents.
`static int`	`getType (char ch)` Returns a value indicating a character's general category.
`static int`	`getType (int codePoint)` Returns a value indicating a character's general category.
`int`	`hashCode ()` Returns a hash code for this `Character`.
`static boolean`	`isDefined (char ch)` Determines if a character is defined in Unicode.
`static boolean`	`isDefined (int codePoint)` Determines if a character (Unicode code point) is defined in Unicode.
`static boolean`	`isDigit (char ch)` Determines if the specified character is a digit.
`static boolean`	`isDigit (int codePoint)` Determines if the specified character (Unicode code point) is a digit.
`static boolean`	`isHighSurrogate (char ch)` Determines if the given `char` value is a high-surrogate code unit (also known as leading-surrogate code unit).
`static boolean`	`isIdentifierIgnorable (char ch)` Determines if the specified character should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
`static boolean`	`isIdentifierIgnorable (int codePoint)` Determines if the specified character (Unicode code point) should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
`static boolean`	`isISOControl (char ch)` Determines if the specified character is an ISO control character.
`static boolean`	`isISOControl (int codePoint)` Determines if the referenced character (Unicode code point) is an ISO control character.
`static boolean`	`isJavaIdentifierPart (char ch)` Determines if the specified character may be part of a Java identifier as other than the first character.
`static boolean`	`isJavaIdentifierPart (int codePoint)` Determines if the character (Unicode code point) may be part of a Java identifier as other than the first character.
`static boolean`	`isJavaIdentifierStart (char ch)` Determines if the specified character is permissible as the first character in a Java identifier.
`static boolean`	`isJavaIdentifierStart (int codePoint)` Determines if the character (Unicode code point) is permissible as the first character in a Java identifier.
`static boolean`	`isJavaLetter (char ch)` Deprecated. Replaced by isJavaIdentifierStart(char).
`static boolean`	`isJavaLetterOrDigit (char ch)` Deprecated. Replaced by isJavaIdentifierPart(char).
`static boolean`	`isLetter (char ch)` Determines if the specified character is a letter.
`static boolean`	`isLetter (int codePoint)` Determines if the specified character (Unicode code point) is a letter.
`static boolean`	`isLetterOrDigit (char ch)` Determines if the specified character is a letter or digit.
`static boolean`	`isLetterOrDigit (int codePoint)` Determines if the specified character (Unicode code point) is a letter or digit.
`static boolean`	`isLowerCase (char ch)` Determines if the specified character is a lowercase character.
`static boolean`	`isLowerCase (int codePoint)` Determines if the specified character (Unicode code point) is a lowercase character.
`static boolean`	`isLowSurrogate (char ch)` Determines if the given `char` value is a

java.lang Class Character

Unicode Character Representations

java.lang
Class Character