Class java.lang.Character
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Class java.lang.Character
Object
|
+----java.lang.Character
- public final class Character
- extends Object
- implements Serializable
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
the type of a character and converting characters from uppercase
to lowercase and vice versa.
Many of the methods of class Character
are defined
in terms of a "Unicode attribute table" that specifies
a name for every defined Unicode code point. The table also
includes other attributes, such as a decimal value, an uppercase
equivalent, a lowercase equivalent, and/or a titlecase equivalent.
The Unicode attribute table is available on the World Wide Web as
the file:
ftp://unicode.org/pub/MappingTables/UnicodeData1.1.5.txt
For a more detailed specification of the Character
class, one that encompasses the exact behavior of methods such as
isDigit
, isLetter
,
isLowerCase
, and isUpperCase
over the
full range of Unicode values, see Gosling, Joy, and Steele, The
Java Language Specification.
- Version:
- 1.44 07/10/98
- Author:
- Lee Boynton, Guy Steele, Akira Tanaka
- Since:
- JDK1.0
-
COMBINING_SPACING_MARK
-
-
CONNECTOR_PUNCTUATION
-
-
CONTROL
-
-
CURRENCY_SYMBOL
-
-
DASH_PUNCTUATION
-
-
DECIMAL_DIGIT_NUMBER
-
-
ENCLOSING_MARK
-
-
END_PUNCTUATION
-
-
FORMAT
-
-
LETTER_NUMBER
-
-
LINE_SEPARATOR
-
-
LOWERCASE_LETTER
-
-
MATH_SYMBOL
-
-
MAX_RADIX
- The maximum radix available for conversion to and from Strings.
-
MAX_VALUE
- The constant value of this field is the largest value of type
char
.
-
MIN_RADIX
- The minimum radix available for conversion to and from Strings.
-
MIN_VALUE
- The constant value of this field is the smallest value of type
char
.
-
MODIFIER_LETTER
-
-
MODIFIER_SYMBOL
-
-
NON_SPACING_MARK
-
-
OTHER_LETTER
-
-
OTHER_NUMBER
-
-
OTHER_PUNCTUATION
-
-
OTHER_SYMBOL
-
-
PARAGRAPH_SEPARATOR
-
-
PRIVATE_USE
-
-
SPACE_SEPARATOR
-
-
START_PUNCTUATION
-
-
SURROGATE
-
-
TITLECASE_LETTER
-
-
TYPE
- The Class object representing the primitive type char.
-
UNASSIGNED
-
-
UPPERCASE_LETTER
-
-
java.lang.Character(char)
- Constructs a
Character
object and initializes it so
that it represents the primitive value
argument.
-
charValue()
- Returns the value of this Character object.
-
digit(char, int)
- Returns the numeric value of the character
ch
in the
specified radix.
-
equals(Object)
- Compares this object against the specified object.
-
forDigit(int, int)
- Determines the character representation for a specific digit in
the specified radix.
-
getNumericValue(char)
- Returns the Unicode numeric value of the character as a
nonnegative integer.
-
getType(char)
- Returns a value indicating a character category.
-
hashCode()
- Returns a hash code for this Character.
-
isDefined(char)
- Determines if a character has a defined meaning in Unicode.
-
isDigit(char)
- Determines if the specified character is a digit.
-
isISOControl(char)
- Determines if the specified character is an ISO control character.
-
isIdentifierIgnorable(char)
- Determines if the specified character should be regarded as
an ignorable character in a Java identifier or a Unicode identifier.
-
isJavaIdentifierPart(char)
- Determines if the specified character may be part of a Java
identifier as other than the first character.
-
isJavaIdentifierStart(char)
- Determines if the specified character is
permissible as the first character in a Java identifier.
-
isJavaLetter(char)
- Determines if the specified character is a
"Java" letter, that is, the character is permissible
as the first character in an identifier in the Java language.
-
isJavaLetterOrDigit(char)
- Determines if the specified character is a
"Java" letter or digit, that is, the character is
permissible as a non-initial character in an identifier in the
Java language.
-
isLetter(char)
- Determines if the specified character is a letter.
-
isLetterOrDigit(char)
- Determines if the specified character is a letter or digit.
-
isLowerCase(char)
- Determines if the specified character is a lowercase character.
-
isSpace(char)
- Determines if the specified character is ISO-LATIN-1 white space.
-
isSpaceChar(char)
- Determines if the specified character is a Unicode space character.
-
isTitleCase(char)
- Determines if the specified character is a titlecase character.
-
isUnicodeIdentifierPart(char)
- Determines if the specified character may be part of a Unicode
identifier as other than the first character.
-
isUnicodeIdentifierStart(char)
- Determines if the specified character is
permissible as the first character in a Unicode identifier.
-
isUpperCase(char)
- Determines if the specified character is an uppercase character.
-
isWhitespace(char)
- Determines if the specified character is white space according to Java.
-
toLowerCase(char)
- The given character is mapped to its lowercase equivalent; if the
character has no lowercase equivalent, the character itself is
returned.
-
toString()
- Returns a String object representing this character's value.
-
toTitleCase(char)
- Converts the character argument to titlecase.
-
toUpperCase(char)
- Converts the character argument to uppercase.
COMBINING_SPACING_MARK
public static final byte COMBINING_SPACING_MARK
CONNECTOR_PUNCTUATION
public static final byte CONNECTOR_PUNCTUATION
CONTROL
public static final byte CONTROL
CURRENCY_SYMBOL
public static final byte CURRENCY_SYMBOL
DASH_PUNCTUATION
public static final byte DASH_PUNCTUATION
DECIMAL_DIGIT_NUMBER
public static final byte DECIMAL_DIGIT_NUMBER
ENCLOSING_MARK
public static final byte ENCLOSING_MARK
END_PUNCTUATION
public static final byte END_PUNCTUATION
FORMAT
public static final byte FORMAT
LETTER_NUMBER
public static final byte LETTER_NUMBER
LINE_SEPARATOR
public static final byte LINE_SEPARATOR
LOWERCASE_LETTER
public static final byte LOWERCASE_LETTER
MATH_SYMBOL
public static final byte MATH_SYMBOL
MAX_RADIX
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
.
- Since:
JDK1.0
- See Also:
- digit(char, int), forDigit(int, int), toString(int, int), valueOf(java.lang.String)
MAX_VALUE
public static final char MAX_VALUE
- The constant value of this field is the largest value of type
char
.
- Since:
JDK1.0.2
MIN_RADIX
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
.
- Since:
JDK1.0
- See Also:
- digit(char, int), forDigit(int, int), toString(int, int), valueOf(java.lang.String)
MIN_VALUE
public static final char MIN_VALUE
- The constant value of this field is the smallest value of type
char
.
- Since:
JDK1.0.2
MODIFIER_LETTER
public static final byte MODIFIER_LETTER
MODIFIER_SYMBOL
public static final byte MODIFIER_SYMBOL
NON_SPACING_MARK
public static final byte NON_SPACING_MARK
OTHER_LETTER
public static final byte OTHER_LETTER
OTHER_NUMBER
public static final byte OTHER_NUMBER
OTHER_PUNCTUATION
public static final byte OTHER_PUNCTUATION
OTHER_SYMBOL
public static final byte OTHER_SYMBOL
PARAGRAPH_SEPARATOR
public static final byte PARAGRAPH_SEPARATOR
PRIVATE_USE
public static final byte PRIVATE_USE
SPACE_SEPARATOR
public static final byte SPACE_SEPARATOR
START_PUNCTUATION
public static final byte START_PUNCTUATION
SURROGATE
public static final byte SURROGATE
TITLECASE_LETTER
public static final byte TITLECASE_LETTER
TYPE
public static final java.lang.Class TYPE
- The Class object representing the primitive type char.
- Since:
JDK1.1
UNASSIGNED
public static final byte UNASSIGNED
UPPERCASE_LETTER
public static final byte UPPERCASE_LETTER
Character
public Character(char value)
- Constructs a
Character
object and initializes it so
that it represents the primitive value
argument.
- Parameters:
- value - value for the new
Character
object.
- Since:
- JDK1.0
charValue
public char charValue()
- Returns the value of this Character object.
- Returns:
- the primitive
char
value represented by
this object.
- Since:
- JDK1.0
digit
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:
- The method
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.
- The character is one of the uppercase Latin letters
'A'
through 'Z'
and its code is less than
radix + 'A' - 10
.
In this case, ch - 'A' + 10
is returned.
- The character is one of the lowercase Latin letters
'a'
through 'z'
and its code is less than
radix + 'a' - 10
.
In this case, ch - 'a' + 10
is returned.
- Parameters:
- ch - the character to be converted.
- radix - the radix.
- Returns:
- the numeric value represented by the character in the
specified radix.
- Since:
- JDK1.0
- See Also:
- forDigit(int, int), isDigit(char)
equals
public boolean equals(Object obj)
- Compares this object against the specified object.
The result is
true
if and only if the argument is not
null
and is a Character
object that
represents the same char
value as this object.
- Parameters:
- obj - the object to compare with.
- Returns:
-
true
if the objects are the same;
false
otherwise.
- Overrides:
- equals in class Object
- Since:
- JDK1.0
forDigit
public static char forDigit(int digit,
int radix)
- Determines the character representation for a specific digit in
the specified radix. If the value of
radix
is not a
valid radix, or the value of digit
is not a valid
digit in the specified radix, the null character
('\u0000'
) is returned.
The radix
argument is valid if it is greater than or
equal to MIN_RADIX
and less than or equal to
MAX_RADIX
. The digit
argument is valid if
0 <= digit <= radix
.
If the digit is less than 10, then
'0' + digit
is returned. Otherwise, the value
'a' + digit - 10
is returned.
- Parameters:
- digit - the number to convert to a character.
- radix - the radix.
- Returns:
- the
char
representation of the specified digit
in the specified radix.
- Since:
- JDK1.0
- See Also:
- MIN_RADIX, MAX_RADIX, digit(char, int)
getNumericValue
public static int getNumericValue(char ch)
- Returns the Unicode numeric value of the character as a
nonnegative integer.
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.
- Parameters:
- ch - the character to be converted.
- radix - the radix.
- Returns:
- the numeric value of the character, as a nonnegative int value;
-2 if the character has a numeric value that is not a
nonnegative integer; -1 if the character has no numeric value.
- Since:
- JDK1.1
- See Also:
- forDigit(char), isDigit(char)
getType
public static int getType(char ch)
- Returns a value indicating a character category.
- Parameters:
- ch - the character to be tested.
- Returns:
- a value of type int, the character category.
- Since:
- JDK1.1
- See Also:
- COMBINING_SPACING_MARK, CONNECTOR_PUNCTUATION, CONTROL, CURRENCY_SYMBOL, DASH_PUNCTUATION, DECIMAL_DIGIT_NUMBER, ENCLOSING_MARK, END_PUNCTUATION, FORMAT, LETTER_NUMBER, LINE_SEPARATOR, LOWERCASE_LETTER, MATH_SYMBOL, MODIFIER_LETTER, MODIFIER_SYMBOL, NON_SPACING_MARK, OTHER_LETTER, OTHER_NUMBER, OTHER_PUNCTUATION, OTHER_SYMBOL, PARAGRAPH_SEPARATOR, PRIVATE_USE, SPACE_SEPARATOR, START_PUNCTUATION, SURROGATE, TITLECASE_LETTER, UNASSIGNED, UPPERCASE_LETTER
hashCode
public int hashCode()
- Returns a hash code for this Character.
- Returns:
- a hash code value for this object.
- Overrides:
- hashCode in class Object
- Since:
- JDK1.0
isDefined
public static boolean isDefined(char ch)
- Determines if a character has a defined meaning in Unicode.
A character is defined if at least one of the following is true:
- It has an entry in the Unicode attribute table.
- Its value is in the range
'\u3040' <= ch <= '\u9FA5'
.
- Its value is in the range
'\uF900' <= ch <= '\uFA2D'
.
- Parameters:
- ch - the character to be tested
- Returns:
-
true
if the character has a defined meaning
in Unicode; false
otherwise.
- Since:
- JDK1.0.2
- See Also:
- isDigit(char), isLetter(char), isLetterOrDigit(char), isLowerCase(char), isTitleCase(char), isUpperCase(char)
isDigit
public static boolean isDigit(char ch)
- Determines if the specified character is a digit.
A character is considered to be a digit if it is not in the range
'\u2000' <= ch <= '\u2FFF'
and its Unicode name contains the word
"DIGIT
". For a more complete
specification that encompasses all Unicode characters that are
defined as digits, see Gosling, Joy, and Steele, The Java
Language Specification.
These are the ranges of Unicode characters that are considered digits:
0x0030 through 0x0039 |
ISO-LATIN-1 digits ('0' through '9') |
0x0660 through 0x0669 | Arabic-Indic digits |
0x06F0 through 0x06F9 |
Extended Arabic-Indic digits |
0x0966 through 0x096F | Devanagari digits |
0x09E6 through 0x09EF | Bengali digits |
0x0A66 through 0x0A6F | Gurmukhi digits |
0x0AE6 through 0x0AEF | Gujarati digits |
0x0B66 through 0x0B6F | Oriya digits |
0x0BE7 through 0x0BEF | Tamil digits |
0x0C66 through 0x0C6F | Telugu digits |
0x0CE6 through 0x0CEF | Kannada digits |
0x0D66 through 0x0D6F | Malayalam digits |
0x0E50 through 0x0E59 | Thai digits |
0x0ED0 through 0x0ED9 | Lao digits |
0x0F20 through 0x0F29 | Tibetan digits |
0xFF10 through 0xFF19 | Fullwidth digits |
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is a digit;
false
otherwise.
- Since:
- JDK1.0
- See Also:
- digit(char, int), forDigit(int, int)
isISOControl
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.
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character is an ISO control character;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isSpaceChar(char), isWhitespace(char)
isIdentifierIgnorable
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:
0x0000 through 0x0008, |
ISO control characters that |
0x000E through 0x001B, | are not whitespace |
and 0x007F through 0x009F |
0x200C through 0x200F | join controls |
0x200A through 0x200E | bidirectional controls |
0x206A through 0x206F | format controls |
0xFEFF | zero-width no-break space |
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character may be part of a Unicode identifier;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isJavaIdentifierPart(char), isUnicodeIdentifierPart(char)
isJavaIdentifierPart
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 and only if
it is one of the following:
- a letter
- a currency symbol (such as "$")
- a connecting punctuation character (such as "_").
- a digit
- a numeric letter (such as a Roman numeral character)
- a combining mark
- a non-spacing mark
- an ignorable control character
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character may be part of a Unicode identifier;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isIdentifierIgnorable(char), isJavaIdentifierStart(char), isLetterOrDigit(char), isUnicodeIdentifierPart(char)
isJavaIdentifierStart
public static boolean isJavaIdentifierStart(char ch)
- Determines if the specified character is
permissible as the first character in a Java identifier.
A character may start a Java identifier if and only if
it is one of the following:
- a letter
- a currency symbol (such as "$")
- a connecting punctuation character (such as "_").
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character may start a Java identifier;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isJavaIdentifierPart(char), isLetter(char), isUnicodeIdentifierStart(char)
isJavaLetter
public static boolean isJavaLetter(char ch)
- Note: isJavaLetter() is deprecated.
Replaced by isJavaIdentifierStart(char).
- Determines if the specified character is a
"Java" letter, that is, the character is permissible
as the first character in an identifier in the Java language.
A character is considered to be a Java letter if and only if it
is a letter, the ASCII dollar sign character '$'
, or
the underscore character '_'
.
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is a Java letter;
false
otherwise.
- Since:
- JDK1.0.2
- See Also:
- isJavaIdentifierStart(char), isJavaLetterOrDigit(char), isLetter(char), isLetterOrDigit(char), isUnicodeIdentifierStart(char)
isJavaLetterOrDigit
public static boolean isJavaLetterOrDigit(char ch)
- Note: isJavaLetterOrDigit() is deprecated.
Replaced by isJavaIdentifierPart(char).
- Determines if the specified character is a
"Java" letter or digit, that is, the character is
permissible as a non-initial character in an identifier in the
Java language.
A character is considered to be a Java letter or digit if and
only if it is a letter, a digit, the ASCII dollar sign character
'$'
, or the underscore character '_'
.
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is a Java letter or digit;
false
otherwise.
- Since:
- JDK1.0.2
- See Also:
- isJavaIdentifierPart(char), isJavaLetter(char), isLetter(char), isLetterOrDigit(char), isUnicodeIdentifierPart(char)
isLetter
public static boolean isLetter(char ch)
- Determines if the specified character is a letter. For a
more complete specification that encompasses all Unicode
characters, see Gosling, Joy, and Steele, The Java Language
Specification.
A character is considered to be a letter if and only if
it is specified to be a letter by the Unicode 2.0 standard
(category "Lu", "Ll", "Lt", "Lm", or "Lo" in the Unicode
specification data file).
Note that most ideographic characters are considered
to be letters (category "Lo") for this purpose.
Note also that not all letters have case: many Unicode characters are
letters but are neither uppercase nor lowercase nor titlecase.
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is a letter;
false
otherwise.
- Since:
- JDK1.0
- See Also:
- isDigit(char), isJavaIdentifierStart(char), isJavaLetter(char), isJavaLetterOrDigit(char), isLetterOrDigit(char), isLowerCase(char), isTitleCase(char), isUnicodeIdentifierStart(char), isUpperCase(char)
isLetterOrDigit
public static boolean isLetterOrDigit(char ch)
- Determines if the specified character is a letter or digit.
For a more complete specification that encompasses all Unicode
characters, see Gosling, Joy, and Steele, The Java Language
Specification.
A character is considered to be a letter if and only if
it is specified to be a letter or a digit by the Unicode 2.0 standard
(category "Lu", "Ll", "Lt", "Lm", "Lo", or "Nd" in the Unicode
specification data file). In other words, isLetterOrDigit is true
of a character if and only if either isLetter is true of the character
or isDigit is true of the character.
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is a letter or digit;
false
otherwise.
- Since:
- JDK1.0.2
- See Also:
- isDigit(char), isJavaIdentifierPart(char), isJavaLetter(char), isJavaLetterOrDigit(char), isLetter(char), isUnicodeIdentifierPart(char)
isLowerCase
public static boolean isLowerCase(char ch)
- Determines if the specified character is a lowercase character.
A character is lowercase if it is not in the range
'\u2000'
through '\u2FFF'
, the Unicode
attribute table does not specify a mapping to lowercase for the
character, and at least one of the following is true:
- The attribute table specifies a mapping to uppercase for the
character.
- The name for the character contains the words "
SMALL
LETTER
".
- The name for the character contains the words "
SMALL
LIGATURE
".
A character is considered to be lowercase if and only if
it is specified to be lowercase by the Unicode 2.0 standard
(category "Ll" in the Unicode specification data file).
Of the ISO-LATIN-1 characters (character codes 0x0000 through 0x00FF),
the following are lowercase:
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.
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is lowercase;
false
otherwise.
- Since:
- JDK1.0
- See Also:
- isLowerCase(char), isTitleCase(char), toLowerCase(char)
isSpace
public static boolean isSpace(char ch)
- Note: isSpace() is deprecated.
Replaced by isWhitespace(char).
- Determines if the specified character is ISO-LATIN-1 white space.
This method returns
true
for the following five
characters only:
'\t' | \u0009 | HORIZONTAL TABULATION |
'\n' | \u000A | NEW LINE |
'\f' | \u000C | FORM FEED |
'\r' | \u000D | CARRIAGE RETURN |
' ' |
\u0020 | SPACE |
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is ISO-LATIN-1 white
space; false
otherwise.
- Since:
- JDK1.0
- See Also:
- isSpaceChar(char), isWhitespace(char)
isSpaceChar
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 2.0 standard
(category "Zs", "Zl, or "Zp" in the Unicode specification data file).
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character is a space character; false otherwise.
- Since:
- JDK1.1
- See Also:
- isWhitespace(char)
isTitleCase
public static boolean isTitleCase(char ch)
- Determines if the specified character is a titlecase character.
A character is considered to be titlecase if and only if
it is specified to be titlecase by the Unicode 2.0 standard
(category "Lt" in the Unicode specification data file).
The printed representations of four Unicode 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 the Unicode characters for which this method returns
true
:
LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
LATIN CAPITAL LETTER L WITH SMALL LETTER J
LATIN CAPITAL LETTER N WITH SMALL LETTER J
LATIN CAPITAL LETTER D WITH SMALL LETTER Z
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is titlecase;
false
otherwise.
- Since:
- JDK1.0.2
- See Also:
- isLowerCase(char), isUpperCase(char), toTitleCase(char)
isUnicodeIdentifierPart
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
it is one of the following:
- a letter
- a connecting punctuation character (such as "_").
- a digit
- a numeric letter (such as a Roman numeral character)
- a combining mark
- a non-spacing mark
- an ignorable control character
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character may be part of a Unicode identifier;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isIdentifierIgnorable(char), isJavaIdentifierPart(char), isLetterOrDigit(char), isUnicodeIdentifierStart(char)
isUnicodeIdentifierStart
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
it is a letter.
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character may start a Unicode identifier;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isJavaIdentifierStart(char), isLetter(char), isUnicodeIdentifierPart(char)
isUpperCase
public static boolean isUpperCase(char ch)
- Determines if the specified character is an uppercase character.
A character is uppercase if it is not in the range
'\u2000'
through '\u2FFF'
, the Unicode
attribute table does not specify a mapping to uppercase for the
character, and at least one of the following is true:
- The attribute table specifies a mapping to lowercase for the
character.
- The name for the character contains the words
"
CAPITAL LETTER
".
- The name for the character contains the words
"
CAPITAL LIGATURE
".
Of the ISO-LATIN-1 characters (character codes 0x0000 through 0x00FF),
the following are uppercase:
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.
- Parameters:
- ch - the character to be tested.
- Returns:
-
true
if the character is uppercase;
false
otherwise.
- Since:
- 1.0
- See Also:
- isLowerCase(char), isTitleCase(char), toUpperCase(char)
isWhitespace
public static boolean isWhitespace(char ch)
- Determines if the specified character is white space according to Java.
A character is considered to be a Java whitespace character if and only
if it satisfies one of the following criteria:
- It is a Unicode space separator (category "Zs"), but is not
a no-break space (\u00A0 or \uFEFF).
- It is a Unicode line separator (category "Zl").
- It is a Unicode paragraph separator (category "Zp").
- It is \u0009, HORIZONTAL TABULATION.
- It is \u000A, LINE FEED.
- It is \u000B, VERTICAL TABULATION.
- It is \u000C, FORM FEED.
- It is \u000D, CARRIAGE RETURN.
- It is \u001C, FILE SEPARATOR.
- It is \u001D, GROUP SEPARATOR.
- It is \u001E, RECORD SEPARATOR.
- It is \u001F, UNIT SEPARATOR.
- Parameters:
- ch - the character to be tested.
- Returns:
- true if the character is a Java whitespace character;
false otherwise.
- Since:
- JDK1.1
- See Also:
- isSpaceChar(char)
toLowerCase
public static char toLowerCase(char ch)
- The given character is mapped to its lowercase equivalent; if the
character has no lowercase equivalent, the character itself is
returned.
A character has a lowercase equivalent if and only if a lowercase
mapping is specified for the character in the Unicode attribute
table.
Note that some Unicode characters in the range
'\u2000'
to '\u2FFF'
have lowercase
mappings; this method does map such characters to their lowercase
equivalents even though the method isUpperCase
does
not return true
for such characters.
- Parameters:
- ch - the character to be converted.
- Returns:
- the lowercase equivalent of the character, if any;
otherwise the character itself.
- Since:
- JDK1.0
- See Also:
- isLowerCase(char), isUpperCase(char), toTitleCase(char), toUpperCase(char)
toString
public java.lang.String toString()
- Returns a String object representing this character's value.
Converts this
Character
object to a string. The
result is a string whose length is 1
. The string's
sole component is the primitive char
value represented
by this object.
- Returns:
- a string representation of this object.
- Overrides:
- toString in class Object
- Since:
- JDK1.0
toTitleCase
public static char toTitleCase(char ch)
- Converts the character argument to titlecase. A character has a
titlecase equivalent if and only if a titlecase mapping is
specified for the character in the Unicode attribute table.
Note that some Unicode characters in the range
'\u2000'
through '\u2FFF'
have titlecase
mappings; this method does map such characters to their titlecase
equivalents even though the method isTitleCase
does
not return true
for such characters.
There are only four Unicode characters that are truly titlecase forms
that are distinct from uppercase forms. As a rule, if a character has no
true titlecase equivalent but does have an uppercase mapping, then the
Unicode 2.0 attribute table specifies a titlecase mapping that is the
same as the uppercase mapping.
- Parameters:
- ch - the character to be converted.
- Returns:
- the titlecase equivalent of the character, if any;
otherwise the character itself.
- Since:
- JDK1.0.2
- See Also:
- isTitleCase(char), toLowerCase(char), toUpperCase(char)
toUpperCase
public static char toUpperCase(char ch)
- Converts the character argument to uppercase. A character has an
uppercase equivalent if and only if an uppercase mapping is
specified for the character in the Unicode attribute table.
Note that some Unicode characters in the range
'\u2000'
to '\u2000FFF'
have uppercase
mappings; this method does map such characters to their titlecase
equivalents even though the method isLowerCase
does
not return true
for such characters.
- Parameters:
- ch - the character to be converted.
- Returns:
- the uppercase equivalent of the character, if any;
otherwise the character itself.
- Since:
- JDK1.0
- See Also:
- isLowerCase(char), isUpperCase(char), toLowerCase(char), toTitleCase(char)
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