Character

Name

Character

Synopsis

Description

The Character class provides an object wrapper for a char value. This is useful when you need to treat a char value as an object. For example, there are a number of utility methods that take a reference to an Object as one of their arguments. You cannot specify a char value for one of these arguments, but you can provide a reference to a Character object that encapsulates the char value. Furthermore, as of JDK 1.1, the Character class is necessary to support the Reflection API and class literals.

In Java, Character objects represent values defined by the Unicode standard. Unicode is defined by an organization called the Unicode Consortium. The defining document for Unicode is The Unicode Standard, Version 2.0 (). More recent information about Unicode is available at http://unicode.org. Appendix a, The Unicode 2.0 Character Set, contains a table that lists the characters defined by the Unicode 2.0 standard.

The Character class provides some utility methods, such as methods for determining the type (e.g., uppercase or lowercase, digit or letter) of a character and for converting from uppercase to lowercase. The logic for these utility methods is based on a Unicode attribute table that is part of the Unicode standard. That table is available at ftp://unicode.org/pub/2.0-Update/UnicodeData-2.0.14.txt.

Some of the methods in the Character class are concerned with characters that are digits; these characters are used by a number of other classes to convert strings that contain numbers into actual numeric values. The digit-related methods all use a radix value to interpret characters. The radix is the numeric base used to represent numbers as characters or strings. Octal is a radix 8 representation, while hexadecimal is a radix 16 representation. The methods that require a radix parameter use it to determine which characters should be treated as valid digits. In radix 2, only the characters `0' and `1' are valid digits. In radix 16, the characters `0' through `9', `a' through `z', and `A' through `Z' are considerd valid digits.

Class Summary

public final class java.lang.Character extends java.lang.Object implements java.io.Serializable {
 // Constants public final static byte COMBINING_SPACING_MARK; // New in 1.1 public final static byte CONNECTOR_PUNCTUATION; // New in 1.1 public final static byte CONTROL; // New in 1.1 public final static byte CURRENCY_SYMBOL; // New in 1.1 public final static byte DASH_PUNCTUATION; // New in 1.1 public final static byte DECIMAL_DIGIT_NUMBER; // New in 1.1 public final static byte ENCLOSING_MARK; // New in 1.1 public final static byte END_PUNCTUATION; // New in 1.1 public final static byte FORMAT; // New in 1.1 public final static byte LETTER_NUMBER; // New in 1.1 public final static byte LINE_SEPARATOR; // New in 1.1 public final static byte LOWERCASE_LETTER; // New in 1.1 public final static byte MATH_SYMBOL; // New in 1.1 public final static int MAX_RADIX;
public final static char MAX_VALUE;
public final static int MIN_RADIX;
public final static char MIN_VALUE;
public final static byte MODIFIER_LETTER; // New in 1.1 public final static byte MODIFIER_SYMBOL; // New in 1.1 public final static byte NON_SPACING_MARK; // New in 1.1 public final static byte OTHER_LETTER; // New in 1.1 public final static byte OTHER_NUMBER; // New in 1.1 public final static byte OTHER_PUNCTUATION; // New in 1.1 public final static byte OTHER_SYMBOL; // New in 1.1 public final static byte PARAGRAPH_SEPARATOR; // New in 1.1 public final static byte PRIVATE_USE; // New in 1.1 public final static byte SPACE_SEPARATOR; // New in 1.1 public final static byte START_PUNCTUATION; // New in 1.1 public final static byte SURROGATE; // New in 1.1 public final static byte TITLECASE_LETTER; // New in 1.1 public final static Class TYPE; // New in 1.1 public final static byte UNASSIGNED; // New in 1.1 public final static byte UPPERCASE_LETTER; // New in 1.1 // Constructors public Character(char value); // Class Methods public static int digit(char ch, int radix);
public static char forDigit(int digit, int radix);
public static int getNumericValue(char ch); // New in 1.1 public static int getType(char ch); // New in 1.1 public static boolean isDefined(char ch);
public static boolean isDigit(char ch);
public static boolean isIdentifierIgnorable(char ch); // New in 1.1 public static boolean isISOControl(char ch); // New in 1.1 public static boolean isJavaIdentifierPart(char ch); // New in 1.1 public static boolean isJavaIdentifierStart(char ch); // New in 1.1 public static boolean isJavaLetter(char ch); // Deprecated in 1.1 public static boolean isJavaLetterOrDigit(char ch); // Deprecated in 1.1 public static boolean isLetter(char ch);
public static boolean isLetterOrDigit(char ch);
public static boolean isLowerCase(char ch);
public static boolean isSpace(char ch); // Deprecated in 1.1 public static boolean isSpaceChar(char ch); // New in 1.1 public static boolean isTitleCase(char ch);
public static boolean isUnicodeIdentifierPart(char ch); // New in 1.1 public static boolean isUnicodeIdentifierStart(char ch);// New in 1.1 public static boolean isUpperCase(char ch);
public static boolean isWhitespace(char ch); // New in 1.1 public static char toLowerCase(char ch);
public static char toTitleCase(char ch);
public static char toUpperCase(char ch); // Instance Methods public char charValue();
public boolean equals(Object obj);
public int hashCode();
public String toString();
}

Constants

COMBINING_SPACING_MARK

public final static byte COMBINING_SPACING_MARK

CONNECTOR_PUNCTUATION

public final static byte CONNECTOR_PUNCTUATION

CONTROL

public final static byte CONTROL

CURRENCY_SYMBOL

public final static byte CURRENCY_SYMBOL

DASH_PUNCTUATION

public final static byte DASH_PUNCTUATION

DECIMAL_DIGIT_NUMBER

public final static byte DECIMAL_DIGIT_NUMBER

ENCLOSING_MARK

public final static byte ENCLOSING_MARK

END_PUNCTUATION

public final static byte END_PUNCTUATION

FORMAT

public final static byte FORMAT

LETTER_NUMBER

public final static byte LETTER_NUMBER

LINE_SEPARATOR

public final static byte LINE_SEPARATOR

LOWERCASE_LETTER

public final static byte LOWERCASE_LETTER

MATH_SYMBOL

public final static byte MATH_SYMBOL

MAX_RADIX

public static final int MAX_RADIX = 36

MAX_VALUE

public final static char MAX_VALUE = '\ufff'f

MIN_RADIX

public static final int MIN_RADIX = 2

MIN_VALUE

public final static char MIN_VALUE = '\u0000'

MODIFIER_LETTER

public final static byte MODIFIER_LETTER

MODIFIER_SYMBOL

public final static byte MODIFIER_SYMBOL

NON_SPACING_MARK

public final static byte NON_SPACING_MARK

OTHER_LETTER

public final static byte OTHER_LETTER

OTHER_NUMBER

public final static byte OTHER_NUMBER

OTHER_PUNCTUATION

public final static byte OTHER_PUNCTUATION

OTHER_SYMBOL

public final static byte OTHER_SYMBOL

PARAGRAPH_SEPARATOR

public final static byte PARAGRAPH_SEPARATOR

PRIVATE_USE

public final static byte PRIVATE_USE

SPACE_SEPARATOR

public final static byte SPACE_SEPARATOR

START_PUNCTUATION

public final static byte START_PUNCTUATION

SURROGATE

public final static byte SURROGATE

TITLECASE_LETTER

public final static byte TITLECASE_LETTER

TYPE

public static final Class TYPE

UNASSIGNED

public final static byte UNASSIGNED

UPPERCASE_LETTER

public final static byte UPPERCASE_LETTER

Constructors

Character

public Character(char value)

Class Methods

digit

public static int digit(char ch, int radix)

forDigit

public static char forDigit(int digit, int radix)

getNumericValue

public static int getNumericValue(char ch)

getType

public static int getType(char ch)

isDefined

public static boolean isDefined(char ch)

isDigit

public static boolean isDigit(char ch)

isIdentifierIgnorable

public static boolean isIdentifierIgnorable(char ch)

isISOControl

public static boolean isISOControl(char ch)

isJavaIdentifierPart

public static boolean isJavaIdentifierPart(char ch)

isJavaIdentifierStart

public static boolean isJavaIdentifierStart(char ch)

isJavaLetter

public static boolean isJavaLetter(char ch)

isJavaLetterOrDigit

public static boolean isJavaLetterOrDigit(char ch)

isLetter

public static boolean isLetter(char ch)

isLetterOrDigit

public static boolean isLetterOrDigit(char ch)

isLowerCase

public static boolean isLowerCase (char ch)

isSpace

public static boolean isSpace(char ch)

isSpaceChar

public static boolean isSpaceChar(char ch)

isTitleCase

public static boolean isTitleCase(char ch)

isUnicodeIdentifierPart

public static boolean isUnicodeIdentifierPart(char ch)

isUnicodeIdentifierStart

public static boolean isUnicodeIdentifierStart(char ch)

isUpperCase

public static boolean isUpperCase(char ch)

isWhitespace

public static boolean isWhitespace(char ch)

toLowerCase

public static char toLowerCase(char ch)

toTitleCase

public static char toTitleCase(char ch)

toUpperCase

public static char toUpperCase(char ch)

Instance Methods

charValue

public char charValue()

equals

public boolean equals(Object obj)

hashCode

public int hashCode()

toString

public String toString()

Inherited Methods

Method Inherited From Method Inherited From
clone() Object finalize() Object
getClass() Object notify() Object
notifyAll() Object wait() Object
wait(long) Object wait(long, int) Object

See Also

Character literals; Class; Integer types; Object