Class Character

java.lang.Object

java.lang.Character

public final class Character
extends Object

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. Character information is based on the Unicode Standard, version 3.0. However, in order to reduce footprint, by default the character property and case conversion operations in CLDC are available only for the ISO Latin-1 range of characters. Other Unicode character blocks can be supported as necessary. Since: JDK1.0, CLDC 1.0

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MAX_CODE_POINT	Maximum code point value - U+10FFFF.
static final char	MAX_HIGH_SURROGATE	Maximum value of a high surrogate or leading surrogate unit in UTF-16 encoding - '?'.
static final char	MAX_LOW_SURROGATE	Maximum value of a low surrogate or trailing surrogate unit in UTF-16 encoding - '?'.
static final int	MAX_RADIX	The maximum radix available for conversion to and from Strings.
static final char	MAX_SURROGATE	Maximum value of a surrogate unit in UTF-16 encoding - '?'.
static final char	MAX_VALUE	The constant value of this field is the largest value of type char.
static final int	MIN_CODE_POINT	Minimum code point value - U+0000.
static final char	MIN_HIGH_SURROGATE	Minimum value of a high surrogate or leading surrogate unit in UTF-16 encoding - '?'.
static final char	MIN_LOW_SURROGATE	Minimum value of a low surrogate or trailing surrogate unit in UTF-16 encoding - '?'.
static final int	MIN_RADIX	The minimum radix available for conversion to and from Strings.
static final int	MIN_SUPPLEMENTARY_CODE_POINT	Minimum value of a supplementary code point - U+010000.
static final char	MIN_SURROGATE	Minimum value of a surrogate unit in UTF-16 encoding - '?'.
static final char	MIN_VALUE	The constant value of this field is the smallest value of type char.
static final int	SIZE	Constant for the number of bits to represent a char in two's compliment form.

Constructor Summary

Constructors

Constructor	Description
Character(char value)	Constructs a Character object and initializes it so that it represents the primitive value argument.

Method Summary

Modifier and Type	Method	Description
static int	charCount(int codePoint)	Calculates the number of char values required to represent the Unicode code point.
char	charValue()	Returns the value of this Character object.
static int	codePointAt(char[] seq, int index)	Returns the code point at the index in the char[].
static int	codePointAt(char[] seq, int index, int limit)	Returns the code point at the index in the char[] that's within the limit.
static int	codePointAt(CharSequence seq, int index)	Returns the code point at the index in the CharSequence.
static int	codePointBefore(char[] seq, int index)	Returns the Unicode code point that proceeds the index in the char[].
static int	codePointBefore(char[] seq, int index, int start)	Returns the Unicode code point that proceeds the index in the char[] and isn't less than start.
static int	codePointBefore(CharSequence seq, int index)	Returns the Unicode code point that proceeds the index in the CharSequence.
static int	codePointCount(char[] seq, int offset, int count)	Counts the number of Unicode code points in the subsequence of the char[], as delineated by the offset and count.
static int	codePointCount(CharSequence seq, int beginIndex, int endIndex)	Counts the number of Unicode code points in the subsequence of the CharSequence, as delineated by the beginIndex and endIndex.
static int	digit(char ch, int radix)	Returns the numeric value of the character ch in the specified radix.
boolean	equals(Object obj)	Compares this object against the specified object.
int	hashCode()	Returns a hash code for this Character.
static boolean	isDigit(char ch)	Determines if the specified character is a digit.
static boolean	isHighSurrogate(char ch)	A test for determining if the char is a high surrogate/leading surrogate unit that's used for representing supplementary characters in UTF-16 encoding.
static boolean	isLowerCase(char ch)	Determines if the specified character is a lowercase character.
static boolean	isLowSurrogate(char ch)	A test for determining if the char is a high surrogate/leading surrogate unit that's used for representing supplementary characters in UTF-16 encoding.
static boolean	isSpace(char ch)
static boolean	isSpaceChar(char ch)
static boolean	isSupplementaryCodePoint(int codePoint)	A test for determining if the codePoint is within the supplementary code point range.
static boolean	isSurrogatePair(char high, char low)	A test for determining if the char pair is a valid surrogate pair.
static boolean	isUpperCase(char ch)	Determines if the specified character is an uppercase character.
static boolean	isValidCodePoint(int codePoint)	A test for determining if the codePoint is a valid Unicode code point.
static boolean	isWhitespace(char c)	See isWhitespace(int).
static boolean	isWhitespace(int codePoint)	Returns true if the given code point is a Unicode whitespace character.
static int	offsetByCodePoints(char[] seq, int start, int count, int index, int codePointOffset)	Determines the index into the char[] that is offset (measured in code points and specified by codePointOffset), from the index argument and is within the subsequence as delineated by start and count.
static int	offsetByCodePoints(CharSequence seq, int index, int codePointOffset)	Determines the index into the CharSequence that is offset (measured in code points and specified by codePointOffset), from the index argument.
static char	reverseBytes(char c)	Reverse the order of the first and second bytes in character
static char[]	toChars(int codePoint)	Converts the Unicode code point, codePoint, into a UTF-16 encoded sequence that is returned as a char[].
static int	toChars(int codePoint, char[] dst, int dstIndex)	Converts the Unicode code point, codePoint, into a UTF-16 encoded sequence and copies the value(s) into the char[] dst, starting at the index dstIndex.
static int	toCodePoint(char high, char low)	Converts a surrogate pair into a Unicode code point.
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.
String	toString()	Returns a String object representing this character's value.
static char	toTitleCase(char c)
static int	toTitleCase(int codePoint)
static char	toUpperCase(char ch)	Converts the character argument to uppercase; if the character has no uppercase equivalent, the character itself is returned.
static Character	valueOf(char i)	Returns the object instance of i

Methods inherited from class Object

clone, getClass, notify, notifyAll, wait, wait, wait

Field Details

MAX_RADIX

public static final int MAX_RADIX

The maximum radix available for conversion to and from Strings. See Also:Integer.toString(int, int), Integer.valueOf(java.lang.String), Constant Field Values

See Also:

• Constant Field Values

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 See Also:Constant Field Values

See Also:

• Constant Field Values

MIN_RADIX

public static final int MIN_RADIX

The minimum radix available for conversion to and from Strings. See Also:Integer.toString(int, int), Integer.valueOf(java.lang.String), Constant Field Values

See Also:

• Constant Field Values

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 See Also:Constant Field Values

See Also:

• Constant Field Values

MIN_HIGH_SURROGATE

public static final char MIN_HIGH_SURROGATE

Minimum value of a high surrogate or leading surrogate unit in UTF-16 encoding - '?'.

Since:

1.5

See Also:

• Constant Field Values

MAX_HIGH_SURROGATE

public static final char MAX_HIGH_SURROGATE

Maximum value of a high surrogate or leading surrogate unit in UTF-16 encoding - '?'.

Since:

1.5

See Also:

• Constant Field Values

MIN_LOW_SURROGATE

public static final char MIN_LOW_SURROGATE

Minimum value of a low surrogate or trailing surrogate unit in UTF-16 encoding - '?'.

Since:

1.5

See Also:

• Constant Field Values

MAX_LOW_SURROGATE

public static final char MAX_LOW_SURROGATE

Maximum value of a low surrogate or trailing surrogate unit in UTF-16 encoding - '?'.

Since:

1.5

See Also:

• Constant Field Values

MIN_SURROGATE

public static final char MIN_SURROGATE

Minimum value of a surrogate unit in UTF-16 encoding - '?'.

Since:

1.5

See Also:

• Constant Field Values

MAX_SURROGATE

public static final char MAX_SURROGATE

Maximum value of a surrogate unit in UTF-16 encoding - '?'.

Since:

1.5

See Also:

• Constant Field Values

MIN_SUPPLEMENTARY_CODE_POINT

public static final int MIN_SUPPLEMENTARY_CODE_POINT

Minimum value of a supplementary code point - U+010000.

Since:

1.5

See Also:

• Constant Field Values

MIN_CODE_POINT

public static final int MIN_CODE_POINT

Minimum code point value - U+0000.

Since:

1.5

See Also:

• Constant Field Values

MAX_CODE_POINT

public static final int MAX_CODE_POINT

Maximum code point value - U+10FFFF.

Since:

1.5

See Also:

• Constant Field Values

SIZE

public static final int SIZE

Constant for the number of bits to represent a char in two's compliment form.

Since:

1.5

See Also:

• Constant Field Values

Constructor Details

Character

public Character(char value)

Constructs a Character object and initializes it so that it represents the primitive value argument. value - value for the new Character object.

Method Details

charValue

public char charValue()

Returns the value of this Character object.

digit

public static int digit(char ch,
 int radix)

Returns the numeric value of the character ch in the specified radix.

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.

Overrides:

equals in class Object

hashCode

public int hashCode()

Returns a hash code for this Character.

Overrides:

hashCode in class Object

isDigit

public static boolean isDigit(char ch)

Determines if the specified character is a digit.

isLowerCase

public static boolean isLowerCase(char ch)

Determines if the specified character is a lowercase character. Note that by default CLDC only supports the ISO Latin-1 range of characters. 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

isUpperCase

public static boolean isUpperCase(char ch)

Determines if the specified character is an uppercase character. Note that by default CLDC only supports the ISO Latin-1 range of characters. 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

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. Note that by default CLDC only supports the ISO Latin-1 range of characters.

toString

public 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.

Overrides:

toString in class Object

toUpperCase

public static char toUpperCase(char ch)

Converts the character argument to uppercase; if the character has no uppercase equivalent, the character itself is returned. Note that by default CLDC only supports the ISO Latin-1 range of characters.

isValidCodePoint

public static boolean isValidCodePoint(int codePoint)

A test for determining if the codePoint is a valid Unicode code point.

Parameters:

codePoint - The code point to test.

Returns:

A boolean value.

Since:

1.5

isSupplementaryCodePoint

public static boolean isSupplementaryCodePoint(int codePoint)

A test for determining if the codePoint is within the supplementary code point range.

Parameters:

codePoint - The code point to test.

Returns:

A boolean value.

Since:

1.5

isHighSurrogate

public static boolean isHighSurrogate(char ch)

A test for determining if the char is a high surrogate/leading surrogate unit that's used for representing supplementary characters in UTF-16 encoding.

Parameters:

ch - The char unit to test.

Returns:

A boolean value.

Since:

1.5

See Also:

• isLowSurrogate(char)

isLowSurrogate

public static boolean isLowSurrogate(char ch)

A test for determining if the char is a high surrogate/leading surrogate unit that's used for representing supplementary characters in UTF-16 encoding.

Parameters:

ch - The char unit to test.

Returns:

A boolean value.

Since:

1.5

See Also:

• isHighSurrogate(char)

isSurrogatePair

public static boolean isSurrogatePair(char high,
 char low)

A test for determining if the char pair is a valid surrogate pair.

Parameters:

high - The high surrogate unit to test.

low - The low surrogate unit to test.

Returns:

A boolean value.

Since:

1.5

See Also:

• isHighSurrogate(char)
• isLowSurrogate(char)

charCount

public static int charCount(int codePoint)

Calculates the number of char values required to represent the Unicode code point. This method only tests if the codePoint is greater than or equal to 0x10000, in which case 2 is returned, otherwise 1. To test if the code point is valid, use the isValidCodePoint(int) method.

Parameters:

codePoint - The code point to test.

Returns:

An int value of 2 or 1.

Since:

1.5

See Also:

• isValidCodePoint(int)
• isSupplementaryCodePoint(int)

toCodePoint

public static int toCodePoint(char high,
 char low)

Converts a surrogate pair into a Unicode code point. This method assume that the pair are valid surrogates. If the pair are NOT valid surrogates, then the result is indeterminate. The isSurrogatePair(char, char) method should be used prior to this method to validate the pair.

Parameters:

high - The high surrogate unit.

low - The low surrogate unit.

Returns:

The decoded code point.

Since:

1.5

See Also:

• isSurrogatePair(char, char)

codePointAt

public static int codePointAt(CharSequence seq,
 int index)

Returns the code point at the index in the CharSequence. If char unit at the index is a high-surrogate unit, the next index is less than the length of the sequence and the char unit at the next index is a low surrogate unit, then the code point represented by the pair is returned; otherwise the char unit at the index is returned.

Parameters:

seq - The sequence of char units.

index - The index into the seq to retrieve and convert.

Returns:

The Unicode code point.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if the index is negative or greater than or equal to seq.length().

Since:

1.5

codePointAt

public static int codePointAt(char[] seq,
 int index)

Returns the code point at the index in the char[]. If char unit at the index is a high-surrogate unit, the next index is less than the length of the sequence and the char unit at the next index is a low surrogate unit, then the code point represented by the pair is returned; otherwise the char unit at the index is returned.

Parameters:

seq - The sequence of char units.

index - The index into the seq to retrieve and convert.

Returns:

The Unicode code point.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if the index is negative or greater than or equal to seq.length().

Since:

1.5

codePointAt

public static int codePointAt(char[] seq,
 int index,
 int limit)

Returns the code point at the index in the char[] that's within the limit. If char unit at the index is a high-surrogate unit, the next index is less than the limit and the char unit at the next index is a low surrogate unit, then the code point represented by the pair is returned; otherwise the char unit at the index is returned.

Parameters:

seq - The sequence of char units.

index - The index into the seq to retrieve and convert.

limit - The exclusive index into the seq that marks the end of the units that can be used.

Returns:

The Unicode code point.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if the index is negative, greater than or equal to limit, limit is negative or limit is greater than the length of seq.

Since:

1.5

codePointBefore

public static int codePointBefore(CharSequence seq,
 int index)

Returns the Unicode code point that proceeds the index in the CharSequence. If the char unit at index - 1 is within the low surrogate range, the value index - 2 isn't negative and the char unit at index - 2 is within the high surrogate range, then the supplementary code point made up of the surrogate pair is returned; otherwise, the char value at index - 1 is returned.

Parameters:

seq - The CharSequence to search.

index - The index into the seq.

Returns:

A Unicode code point.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if index is less than 1 or greater than seq.length().

Since:

1.5

codePointBefore

public static int codePointBefore(char[] seq,
 int index)

Returns the Unicode code point that proceeds the index in the char[]. If the char unit at index - 1 is within the low surrogate range, the value index - 2 isn't negative and the char unit at index - 2 is within the high surrogate range, then the supplementary code point made up of the surrogate pair is returned; otherwise, the char value at index - 1 is returned.

Parameters:

seq - The char[] to search.

index - The index into the seq.

Returns:

A Unicode code point.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if index is less than 1 or greater than seq.length.

Since:

1.5

codePointBefore

public static int codePointBefore(char[] seq,
 int index,
 int start)

Returns the Unicode code point that proceeds the index in the char[] and isn't less than start. If the char unit at index - 1 is within the low surrogate range, the value index - 2 isn't less than start and the char unit at index - 2 is within the high surrogate range, then the supplementary code point made up of the surrogate pair is returned; otherwise, the char value at index - 1 is returned.

Parameters:

seq - The char[] to search.

index - The index into the seq.

Returns:

A Unicode code point.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if index is less than or equal to start, index is greater than seq.length, start is not negative and start is greater than seq.length.

Since:

1.5

toChars

public static int toChars(int codePoint,
 char[] dst,
 int dstIndex)

Converts the Unicode code point, codePoint, into a UTF-16 encoded sequence and copies the value(s) into the char[] dst, starting at the index dstIndex.

Parameters:

codePoint - The Unicode code point to encode.

dst - The char[] to copy the encoded value into.

dstIndex - The index to start copying into dst.

Returns:

The number of char value units copied into dst.

Throws:

IllegalArgumentException - if codePoint is not a valid Unicode code point.

NullPointerException - if dst is null.

IndexOutOfBoundsException - if dstIndex is negative, greater than or equal to dst.length or equals dst.length - 1 when codePoint is a supplementary code point.

Since:

1.5

toChars

public static char[] toChars(int codePoint)

Converts the Unicode code point, codePoint, into a UTF-16 encoded sequence that is returned as a char[].

Parameters:

codePoint - The Unicode code point to encode.

Returns:

The UTF-16 encoded char sequence; if code point is a supplementary code point, then a 2 char array is returned, otherwise a 1 char array is returned.

Throws:

IllegalArgumentException - if codePoint is not a valid Unicode code point.

Since:

1.5

codePointCount

public static int codePointCount(CharSequence seq,
 int beginIndex,
 int endIndex)

Counts the number of Unicode code points in the subsequence of the CharSequence, as delineated by the beginIndex and endIndex. Any surrogate values with missing pair values will be counted as 1 code point.

Parameters:

seq - The CharSequence to look through.

beginIndex - The inclusive index to begin counting at.

endIndex - The exclusive index to stop counting at.

Returns:

The number of Unicode code points.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if beginIndex is negative, greater than seq.length() or greater than endIndex.

Since:

1.5

codePointCount

public static int codePointCount(char[] seq,
 int offset,
 int count)

Counts the number of Unicode code points in the subsequence of the char[], as delineated by the offset and count. Any surrogate values with missing pair values will be counted as 1 code point.

Parameters:

seq - The char[] to look through.

offset - The inclusive index to begin counting at.

count - The number of char values to look through in seq.

Returns:

The number of Unicode code points.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if offset or count is negative or if endIndex is greater than seq.length.

Since:

1.5

offsetByCodePoints

public static int offsetByCodePoints(CharSequence seq,
 int index,
 int codePointOffset)

Determines the index into the CharSequence that is offset (measured in code points and specified by codePointOffset), from the index argument.

Parameters:

seq - The CharSequence to find the index within.

index - The index to begin from, within the CharSequence.

codePointOffset - The number of code points to look back or forwards; may be a negative or positive value.

Returns:

The calculated index that is codePointOffset code points from index.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if index is negative, greater than seq.length(), there aren't enough values in seq after index or before index if codePointOffset is negative.

Since:

1.5

offsetByCodePoints

public static int offsetByCodePoints(char[] seq,
 int start,
 int count,
 int index,
 int codePointOffset)

Determines the index into the char[] that is offset (measured in code points and specified by codePointOffset), from the index argument and is within the subsequence as delineated by start and count.

Parameters:

seq - The char[] to find the index within.

start - The inclusive index that marks the beginning of the subsequence.

count - The number of char values to include within the subsequence.

index - The index to begin from, within the char[].

codePointOffset - The number of code points to look back or forwards; may be a negative or positive value.

Returns:

The calculated index that is codePointOffset code points from index.

Throws:

NullPointerException - if seq is null.

IndexOutOfBoundsException - if start or count is negative, start + count greater than seq.length, index is less than start, index is greater than start + count or there aren't enough values in seq after index or before index if codePointOffset is negative.

Since:

1.5

reverseBytes

public static char reverseBytes(char c)

Reverse the order of the first and second bytes in character

Parameters:

c - the character

Returns:

the character with reordered bytes.

valueOf

public static Character valueOf(char i)

Returns the object instance of i

Parameters:

i - the primitive

Returns:

object instance

isWhitespace

public static boolean isWhitespace(char c)

See isWhitespace(int).

isSpace

public static boolean isSpace(char ch)

isSpaceChar

public static boolean isSpaceChar(char ch)

isWhitespace

public static boolean isWhitespace(int codePoint)

Returns true if the given code point is a Unicode whitespace character. The exact set of characters considered as whitespace varies with Unicode version. Note that non-breaking spaces are not considered whitespace. Note also that line separators are considered whitespace; see isSpaceChar(char) for an alternative.

toTitleCase

public static int toTitleCase(int codePoint)

toTitleCase

public static char toTitleCase(char c)