UCharacter

public final class UCharacter extends Object
implements UCharacterEnums.ECharacterCategory UCharacterEnums.ECharacterDirection

[icu enhancement] ICU's replacement for Character. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.

The UCharacter class provides extensions to the Character class. These extensions provide support for more Unicode properties. Each ICU release supports the latest version of Unicode available at that time.

For some time before Java 5 added support for supplementary Unicode code points, The ICU UCharacter class and many other ICU classes already supported them. Some UCharacter methods and constants were widened slightly differently than how the Character class methods and constants were widened later. In particular, MAX_VALUE is still a char with the value U+FFFF, while the MAX_VALUE is an int with the value U+10FFFF.

Code points are represented in these API using ints. While it would be more convenient in Java to have a separate primitive datatype for them, ints suffice in the meantime.

Aside from the additions for UTF-16 support, and the updated Unicode properties, the main differences between UCharacter and Character are:

  • UCharacter is not designed to be a char wrapper and does not have APIs to which involves management of that single char.
    These include:
    • char charValue(),
    • int compareTo(java.lang.Character, java.lang.Character), etc.
  • UCharacter does not include Character APIs that are deprecated, nor does it include the Java-specific character information, such as boolean isJavaIdentifierPart(char ch).
  • Character maps characters 'A' - 'Z' and 'a' - 'z' to the numeric values '10' - '35'. UCharacter also does this in digit and getNumericValue, to adhere to the java semantics of these methods. New methods unicodeDigit, and getUnicodeNumericValue do not treat the above code points as having numeric values. This is a semantic change from ICU4J 1.3.1.

In addition to Java compatibility functions, which calculate derived properties, this API provides low-level access to the Unicode Character Database.

Unicode assigns each code point (not just assigned character) values for many properties. Most of them are simple boolean flags, or constants from a small enumerated list. For some properties, values are strings or other relatively more complex types.

For more information see "About the Unicode Character Database" (http://www.unicode.org/ucd/) and the ICU User Guide chapter on Properties (http://www.icu-project.org/userguide/properties.html).

There are also functions that provide easy migration from C/POSIX functions like isblank(). Their use is generally discouraged because the C/POSIX standards do not define their semantics beyond the ASCII range, which means that different implementations exhibit very different behavior. Instead, Unicode properties should be used directly.

There are also only a few, broad C/POSIX character classes, and they tend to be used for conflicting purposes. For example, the "isalpha()" class is sometimes used to determine word boundaries, while a more sophisticated approach would at least distinguish initial letters from continuation characters (the latter including combining marks). (In ICU, BreakIterator is the most sophisticated API for word boundaries.) Another example: There is no "istitle()" class for titlecase characters.

ICU 3.4 and later provides API access for all twelve C/POSIX character classes. ICU implements them according to the Standard Recommendations in Annex C: Compatibility Properties of UTS #18 Unicode Regular Expressions (http://www.unicode.org/reports/tr18/#Compatibility_Properties).

API access for C/POSIX character classes is as follows:

- alpha:     isUAlphabetic(c) or hasBinaryProperty(c, UProperty.ALPHABETIC)
 - lower:     isULowercase(c) or hasBinaryProperty(c, UProperty.LOWERCASE)
 - upper:     isUUppercase(c) or hasBinaryProperty(c, UProperty.UPPERCASE)
 - punct:     ((1<<getType(c)) & ((1<<DASH_PUNCTUATION)|(1<<START_PUNCTUATION)|
               (1<<END_PUNCTUATION)|(1<<CONNECTOR_PUNCTUATION)|(1<<OTHER_PUNCTUATION)|
               (1<<INITIAL_PUNCTUATION)|(1<<FINAL_PUNCTUATION)))!=0
 - digit:     isDigit(c) or getType(c)==DECIMAL_DIGIT_NUMBER
 - xdigit:    hasBinaryProperty(c, UProperty.POSIX_XDIGIT)
 - alnum:     hasBinaryProperty(c, UProperty.POSIX_ALNUM)
 - space:     isUWhiteSpace(c) or hasBinaryProperty(c, UProperty.WHITE_SPACE)
 - blank:     hasBinaryProperty(c, UProperty.POSIX_BLANK)
 - cntrl:     getType(c)==CONTROL
 - graph:     hasBinaryProperty(c, UProperty.POSIX_GRAPH)
 - print:     hasBinaryProperty(c, UProperty.POSIX_PRINT)

The C/POSIX character classes are also available in UnicodeSet patterns, using patterns like [:graph:] or \p{graph}.

[icu] Note: There are several ICU (and Java) whitespace functions. Comparison:

  • isUWhiteSpace=UCHAR_WHITE_SPACE: Unicode White_Space property; most of general categories "Z" (separators) + most whitespace ISO controls (including no-break spaces, but excluding IS1..IS4 and ZWSP)
  • isWhitespace: Java isWhitespace; Z + whitespace ISO controls but excluding no-break spaces
  • isSpaceChar: just Z (including no-break spaces)

This class is not subclassable.

See Also

Nested Class Summary

interface UCharacter.BidiPairedBracketType Bidi Paired Bracket Type constants. 
interface UCharacter.DecompositionType Decomposition Type constants. 
interface UCharacter.EastAsianWidth East Asian Width constants. 
interface UCharacter.GraphemeClusterBreak Grapheme Cluster Break constants. 
interface UCharacter.HangulSyllableType Hangul Syllable Type constants. 
interface UCharacter.JoiningGroup Joining Group constants. 
interface UCharacter.JoiningType Joining Type constants. 
interface UCharacter.LineBreak Line Break constants. 
interface UCharacter.NumericType Numeric Type constants. 
interface UCharacter.SentenceBreak Sentence Break constants. 
class UCharacter.UnicodeBlock [icu enhancement] ICU's replacement for Character.UnicodeBlock. Methods, fields, and other functionality specific to ICU are labeled '[icu]'. 
interface UCharacter.WordBreak Word Break constants. 

Constant Summary

int FOLD_CASE_DEFAULT [icu] Option value for case folding: use default mappings defined in CaseFolding.txt.
int FOLD_CASE_EXCLUDE_SPECIAL_I [icu] Option value for case folding: Use the modified set of mappings provided in CaseFolding.txt to handle dotted I and dotless i appropriately for Turkic languages (tr, az).
int MAX_CODE_POINT Constant U+10FFFF, same as MAX_CODE_POINT.
char MAX_HIGH_SURROGATE Constant U+DBFF, same as MAX_HIGH_SURROGATE.
char MAX_LOW_SURROGATE Constant U+DFFF, same as MAX_LOW_SURROGATE.
int MAX_RADIX Compatibility constant for Java Character's MAX_RADIX.
char MAX_SURROGATE Constant U+DFFF, same as MAX_SURROGATE.
int MAX_VALUE The highest Unicode code point value (scalar value), constant U+10FFFF (uses 21 bits).
int MIN_CODE_POINT Constant U+0000, same as MIN_CODE_POINT.
char MIN_HIGH_SURROGATE Constant U+D800, same as MIN_HIGH_SURROGATE.
char MIN_LOW_SURROGATE Constant U+DC00, same as MIN_LOW_SURROGATE.
int MIN_RADIX Compatibility constant for Java Character's MIN_RADIX.
int MIN_SUPPLEMENTARY_CODE_POINT Constant U+10000, same as MIN_SUPPLEMENTARY_CODE_POINT.
char MIN_SURROGATE Constant U+D800, same as MIN_SURROGATE.
int MIN_VALUE The lowest Unicode code point value, constant 0.
double NO_NUMERIC_VALUE Special value that is returned by getUnicodeNumericValue(int) when no numeric value is defined for a code point.
int REPLACEMENT_CHAR Unicode value used when translating into Unicode encoding form and there is no existing character.
int SUPPLEMENTARY_MIN_VALUE The minimum value for Supplementary code points, constant U+10000.
int TITLECASE_NO_BREAK_ADJUSTMENT Do not adjust the titlecasing indexes from BreakIterator::next() indexes; titlecase exactly the characters at breaks from the iterator.
int TITLECASE_NO_LOWERCASE Do not lowercase non-initial parts of words when titlecasing.

Inherited Constant Summary

Public Method Summary

static int
charCount(int cp)
static int
codePointAt(char[] text, int index, int limit)
static int
codePointAt(char[] text, int index)
static int
static int
codePointBefore(char[] text, int index)
static int
static int
codePointBefore(char[] text, int index, int limit)
static int
codePointCount(CharSequence text, int start, int limit)
Equivalent to the codePointCount(CharSequence, int, int) method, for convenience.
static int
codePointCount(char[] text, int start, int limit)
Equivalent to the codePointCount(char[], int, int) method, for convenience.
static int
digit(int ch)
Returnss the numeric value of a decimal digit code point.
static int
digit(int ch, int radix)
Returnss the numeric value of a decimal digit code point.
static String
foldCase(String str, boolean defaultmapping)
[icu] The given string is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if any character has no case folding equivalent, the character itself is returned.
static int
foldCase(int ch, boolean defaultmapping)
[icu] The given character is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if the character has no case folding equivalent, the character itself is returned.
static int
foldCase(int ch, int options)
[icu] The given character is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if the character has no case folding equivalent, the character itself is returned.
static String
foldCase(String str, int options)
[icu] The given string is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if any character has no case folding equivalent, the character itself is returned.
static char
forDigit(int digit, int radix)
Provide the java.lang.Character forDigit API, for convenience.
static VersionInfo
getAge(int ch)
[icu] Returns the "age" of the code point.
static int
getBidiPairedBracket(int c)
[icu] Maps the specified character to its paired bracket character.
static int
getCharFromExtendedName(String name)
[icu]

Find a Unicode character by either its name and return its code point value.

static int
getCharFromName(String name)
[icu]

Finds a Unicode code point by its most current Unicode name and return its code point value.

static int
getCharFromNameAlias(String name)
[icu]

Find a Unicode character by its corrected name alias and return its code point value.

static int
getCodePoint(char char16)
[icu] Returns the code point corresponding to the BMP code point.
static int
getCodePoint(char lead, char trail)
[icu] Returns a code point corresponding to the two surrogate code units.
static int
getCombiningClass(int ch)
[icu] Returns the combining class of the argument codepoint
static int
getDirection(int ch)
[icu] Returns the Bidirection property of a code point.
static byte
getDirectionality(int cp)
Equivalent to the getDirectionality(char) method, for convenience.
static String
getExtendedName(int ch)
[icu] Returns a name for a valid codepoint.
static ValueIterator
getExtendedNameIterator()
[icu]

Returns an iterator for character names, iterating over codepoints.

static int
getHanNumericValue(int ch)
[icu] Returns the numeric value of a Han character.
static int
getIntPropertyMaxValue(int type)
[icu] Returns the maximum value for an integer/binary Unicode property.
static int
getIntPropertyMinValue(int type)
[icu] Returns the minimum value for an integer/binary Unicode property type.
static int
getIntPropertyValue(int ch, int type)
[icu]

Returns the property value for an Unicode property type of a code point.

static int
getMirror(int ch)
[icu] Maps the specified code point to a "mirror-image" code point.
static String
getName(int ch)
[icu] Returns the most current Unicode name of the argument code point, or null if the character is unassigned or outside the range UCharacter.MIN_VALUE and UCharacter.MAX_VALUE or does not have a name.
static String
getName(String s, String separator)
[icu] Returns the names for each of the characters in a string
static String
getNameAlias(int ch)
[icu] Returns the corrected name from NameAliases.txt if there is one.
static ValueIterator
getNameIterator()
[icu]

Returns an iterator for character names, iterating over codepoints.

static int
getNumericValue(int ch)
Returns the numeric value of the code point as a nonnegative integer.
static int
getPropertyEnum(CharSequence propertyAlias)
[icu] Return the UProperty selector for a given property name, as specified in the Unicode database file PropertyAliases.txt.
static String
getPropertyName(int property, int nameChoice)
[icu] Return the Unicode name for a given property, as given in the Unicode database file PropertyAliases.txt.
static int
getPropertyValueEnum(int property, CharSequence valueAlias)
[icu] Return the property value integer for a given value name, as specified in the Unicode database file PropertyValueAliases.txt.
static String
getPropertyValueName(int property, int value, int nameChoice)
[icu] Return the Unicode name for a given property value, as given in the Unicode database file PropertyValueAliases.txt.
static int
getType(int ch)
Returns a value indicating a code point's Unicode category.
static RangeValueIterator
getTypeIterator()
[icu]

Returns an iterator for character types, iterating over codepoints.

static double
getUnicodeNumericValue(int ch)
[icu] Returns the numeric value for a Unicode code point as defined in the Unicode Character Database.
static VersionInfo
getUnicodeVersion()
[icu] Returns the version of Unicode data used.
static boolean
hasBinaryProperty(int ch, int property)
[icu]

Check a binary Unicode property for a code point.

static boolean
isBMP(int ch)
[icu] Determines if the code point is in the BMP plane.
static boolean
isBaseForm(int ch)
[icu] Determines whether the specified code point is of base form.
static boolean
isDefined(int ch)
Determines if a code point has a defined meaning in the up-to-date Unicode standard.
static boolean
isDigit(int ch)
Determines if a code point is a Java digit.
static boolean
static boolean
isISOControl(int ch)
Determines if the specified code point is an ISO control character.
static boolean
isIdentifierIgnorable(int ch)
Determines if the specified code point should be regarded as an ignorable character in a Java identifier.
static boolean
isJavaIdentifierPart(int cp)
Compatibility override of Java method, delegates to java.lang.Character.isJavaIdentifierPart.
static boolean
isJavaIdentifierStart(int cp)
Compatibility override of Java method, delegates to java.lang.Character.isJavaIdentifierStart.
static boolean
isLegal(int ch)
[icu] A code point is illegal if and only if
  • Out of bounds, less than 0 or greater than UCharacter.MAX_VALUE
  • A surrogate value, 0xD800 to 0xDFFF
  • Not-a-character, having the form 0x xxFFFF or 0x xxFFFE
Note: legal does not mean that it is assigned in this version of Unicode.
static boolean
isLegal(String str)
[icu] A string is legal iff all its code points are legal.
static boolean
isLetter(int ch)
Determines if the specified code point is a letter.
static boolean
isLetterOrDigit(int ch)
Determines if the specified code point is a letter or digit.
static boolean
static boolean
isLowerCase(int ch)
Determines if the specified code point is a lowercase character.
static boolean
isMirrored(int ch)
Determines whether the code point has the "mirrored" property.
static boolean
isPrintable(int ch)
[icu] Determines whether the specified code point is a printable character according to the Unicode standard.
static boolean
isSpaceChar(int ch)
Determines if the specified code point is a Unicode specified space character, i.e.
static boolean
isSupplementary(int ch)
[icu] Determines if the code point is a supplementary character.
static boolean
static boolean
isSurrogatePair(char high, char low)
static boolean
isTitleCase(int ch)
Determines if the specified code point is a titlecase character.
static boolean
isUAlphabetic(int ch)
[icu]

Check if a code point has the Alphabetic Unicode property.

static boolean
isULowercase(int ch)
[icu]

Check if a code point has the Lowercase Unicode property.

static boolean
isUUppercase(int ch)
[icu]

Check if a code point has the Uppercase Unicode property.

static boolean
isUWhiteSpace(int ch)
[icu]

Check if a code point has the White_Space Unicode property.

static boolean
isUnicodeIdentifierPart(int ch)
Determines if the specified code point may be any part of a Unicode identifier other than the starting character.
static boolean
isUnicodeIdentifierStart(int ch)
Determines if the specified code point is permissible as the first character in a Unicode identifier.
static boolean
isUpperCase(int ch)
Determines if the specified code point is an uppercase character.
static boolean
isValidCodePoint(int cp)
Equivalent to isValidCodePoint(int).
static boolean
isWhitespace(int ch)
Determines if the specified code point is a white space character.
static int
offsetByCodePoints(CharSequence text, int index, int codePointOffset)
Equivalent to the offsetByCodePoints(CharSequence, int, int) method, for convenience.
static int
offsetByCodePoints(char[] text, int start, int count, int index, int codePointOffset)
Equivalent to the offsetByCodePoints(char[], int, int, int, int) method, for convenience.
static int
toChars(int cp, char[] dst, int dstIndex)
static char[]
toChars(int cp)
Same as toChars(int).
static int
toCodePoint(char high, char low)
static String
toLowerCase(String str)
Returns the lowercase version of the argument string.
static int
toLowerCase(int ch)
The given code point is mapped to its lowercase equivalent; if the code point has no lowercase equivalent, the code point itself is returned.
static String
toLowerCase(ULocale locale, String str)
Returns the lowercase version of the argument string.
static String
toLowerCase(Locale locale, String str)
Returns the lowercase version of the argument string.
static String
toString(int ch)
Converts argument code point and returns a String object representing the code point's value in UTF-16 format.
static String
toTitleCase(Locale locale, String str, BreakIterator titleIter, int options)
[icu]

Returns the titlecase version of the argument string.

static String
toTitleCase(ULocale locale, String str, BreakIterator titleIter)

Returns the titlecase version of the argument string.

static String
toTitleCase(String str, BreakIterator breakiter)

Returns the titlecase version of the argument string.

static String
toTitleCase(ULocale locale, String str, BreakIterator titleIter, int options)

Returns the titlecase version of the argument string.

static String
toTitleCase(Locale locale, String str, BreakIterator breakiter)

Returns the titlecase version of the argument string.

static int
toTitleCase(int ch)
Converts the code point argument to titlecase.
static String
toUpperCase(Locale locale, String str)
Returns the uppercase version of the argument string.
static String
toUpperCase(ULocale locale, String str)
Returns the uppercase version of the argument string.
static int
toUpperCase(int ch)
Converts the character argument to uppercase.
static String
toUpperCase(String str)
Returns the uppercase version of the argument string.

Inherited Method Summary

Constants

public static final int FOLD_CASE_DEFAULT

[icu] Option value for case folding: use default mappings defined in CaseFolding.txt.

Constant Value: 0

public static final int FOLD_CASE_EXCLUDE_SPECIAL_I

[icu] Option value for case folding: Use the modified set of mappings provided in CaseFolding.txt to handle dotted I and dotless i appropriately for Turkic languages (tr, az).

Before Unicode 3.2, CaseFolding.txt contains mappings marked with 'I' that are to be included for default mappings and excluded for the Turkic-specific mappings.

Unicode 3.2 CaseFolding.txt instead contains mappings marked with 'T' that are to be excluded for default mappings and included for the Turkic-specific mappings.

Constant Value: 1

public static final int MAX_CODE_POINT

Constant U+10FFFF, same as MAX_CODE_POINT.

Constant Value: 1114111

public static final char MAX_HIGH_SURROGATE

Constant U+DBFF, same as MAX_HIGH_SURROGATE.

Constant Value: 56319

public static final char MAX_LOW_SURROGATE

Constant U+DFFF, same as MAX_LOW_SURROGATE.

Constant Value: 57343

public static final int MAX_RADIX

Compatibility constant for Java Character's MAX_RADIX.

Constant Value: 36

public static final char MAX_SURROGATE

Constant U+DFFF, same as MAX_SURROGATE.

Constant Value: 57343

public static final int MAX_VALUE

The highest Unicode code point value (scalar value), constant U+10FFFF (uses 21 bits). Same as MAX_CODE_POINT.

Up-to-date Unicode implementation of MAX_VALUE which is still a char with the value U+FFFF.

Constant Value: 1114111

public static final int MIN_CODE_POINT

Constant U+0000, same as MIN_CODE_POINT.

Constant Value: 0

public static final char MIN_HIGH_SURROGATE

Constant U+D800, same as MIN_HIGH_SURROGATE.

Constant Value: 55296

public static final char MIN_LOW_SURROGATE

Constant U+DC00, same as MIN_LOW_SURROGATE.

Constant Value: 56320

public static final int MIN_RADIX

Compatibility constant for Java Character's MIN_RADIX.

Constant Value: 2

public static final int MIN_SUPPLEMENTARY_CODE_POINT

Constant U+10000, same as MIN_SUPPLEMENTARY_CODE_POINT.

Constant Value: 65536

public static final char MIN_SURROGATE

Constant U+D800, same as MIN_SURROGATE.

Constant Value: 55296

public static final int MIN_VALUE

The lowest Unicode code point value, constant 0. Same as MIN_CODE_POINT, same integer value as MIN_VALUE.

Constant Value: 0

public static final double NO_NUMERIC_VALUE

Special value that is returned by getUnicodeNumericValue(int) when no numeric value is defined for a code point.

Constant Value: -1.23456789E8

public static final int REPLACEMENT_CHAR

Unicode value used when translating into Unicode encoding form and there is no existing character.

Constant Value: 65533

public static final int SUPPLEMENTARY_MIN_VALUE

The minimum value for Supplementary code points, constant U+10000. Same as MIN_SUPPLEMENTARY_CODE_POINT.

Constant Value: 65536

public static final int TITLECASE_NO_BREAK_ADJUSTMENT

Do not adjust the titlecasing indexes from BreakIterator::next() indexes; titlecase exactly the characters at breaks from the iterator. Option bit for titlecasing APIs that take an options bit set. By default, titlecasing will take each break iterator index, adjust it by looking for the next cased character, and titlecase that one. Other characters are lowercased. This follows Unicode 4 & 5 section 3.13 Default Case Operations: R3 toTitlecase(X): Find the word boundaries based on Unicode Standard Annex #29, "Text Boundaries." Between each pair of word boundaries, find the first cased character F. If F exists, map F to default_title(F); then map each subsequent character C to default_lower(C).

Constant Value: 512

public static final int TITLECASE_NO_LOWERCASE

Do not lowercase non-initial parts of words when titlecasing. Option bit for titlecasing APIs that take an options bit set. By default, titlecasing will titlecase the first cased character of a word and lowercase all other characters. With this option, the other characters will not be modified.

Constant Value: 256

Public Methods

public static int charCount (int cp)

Same as charCount(int). Returns the number of chars needed to represent the code point (1 or 2). This does not check the code point for validity.

Parameters
cp the code point to check
Returns
  • the number of chars needed to represent the code point

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

Same as codePointAt(char[], int, int). Returns the code point at index. This examines only the characters at index and index+1.

Parameters
text the characters to check
index the index of the first or only char forming the code point
limit the limit of the valid text
Returns
  • the code point at the index

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

Same as codePointAt(char[], int). Returns the code point at index. This examines only the characters at index and index+1.

Parameters
text the characters to check
index the index of the first or only char forming the code point
Returns
  • the code point at the index

public static int codePointAt (CharSequence seq, int index)

Same as codePointAt(CharSequence, int). Returns the code point at index. This examines only the characters at index and index+1.

Parameters
seq the characters to check
index the index of the first or only char forming the code point
Returns
  • the code point at the index

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

Same as codePointBefore(char[], int). Returns the code point before index. This examines only the characters at index-1 and index-2.

Parameters
text the characters to check
index the index after the last or only char forming the code point
Returns
  • the code point before the index

public static int codePointBefore (CharSequence seq, int index)

Same as codePointBefore(CharSequence, int). Return the code point before index. This examines only the characters at index-1 and index-2.

Parameters
seq the characters to check
index the index after the last or only char forming the code point
Returns
  • the code point before the index

public static int codePointBefore (char[] text, int index, int limit)

Same as codePointBefore(char[], int, int). Return the code point before index. This examines only the characters at index-1 and index-2.

Parameters
text the characters to check
index the index after the last or only char forming the code point
limit the start of the valid text
Returns
  • the code point before the index

public static int codePointCount (CharSequence text, int start, int limit)

Equivalent to the codePointCount(CharSequence, int, int) method, for convenience. Counts the number of code points in the range of text.

Parameters
text the characters to check
start the start of the range
limit the limit of the range
Returns
  • the number of code points in the range

public static int codePointCount (char[] text, int start, int limit)

Equivalent to the codePointCount(char[], int, int) method, for convenience. Counts the number of code points in the range of text.

Parameters
text the characters to check
start the start of the range
limit the limit of the range
Returns
  • the number of code points in the range

public static int digit (int ch)

Returnss the numeric value of a decimal digit code point.
This is a convenience overload of digit(int, int) that provides a decimal radix.
Semantic Change: In release 1.3.1 and prior, this treated numeric letters and other numbers as digits. This has been changed to conform to the java semantics.

Parameters
ch the code point to query
Returns
  • the numeric value represented by the code point, or -1 if the code point is not a decimal digit or if its value is too large for a decimal radix

public static int digit (int ch, int radix)

Returnss the numeric value of a decimal digit code point.
This method observes the semantics of java.lang.Character.digit(). Note that this will return positive values for code points for which isDigit returns false, just like java.lang.Character.
Semantic Change: In release 1.3.1 and prior, this did not treat the European letters as having a digit value, and also treated numeric letters and other numbers as digits. This has been changed to conform to the java semantics.
A code point is a valid digit if and only if:

  • ch is a decimal digit or one of the european letters, and
  • the value of ch is less than the specified radix.

Parameters
ch the code point to query
radix the radix
Returns
  • the numeric value represented by the code point in the specified radix, or -1 if the code point is not a decimal digit or if its value is too large for the radix

public static String foldCase (String str, boolean defaultmapping)

[icu] The given string is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if any character has no case folding equivalent, the character itself is returned. "Full", multiple-code point case folding mappings are returned here. For "simple" single-code point mappings use the API foldCase(int ch, boolean defaultmapping).

Parameters
str the String to be converted
defaultmapping Indicates whether the default mappings defined in CaseFolding.txt are to be used, otherwise the mappings for dotted I and dotless i marked with 'T' in CaseFolding.txt are included.
Returns
  • the case folding equivalent of the character, if any; otherwise the character itself.

public static int foldCase (int ch, boolean defaultmapping)

[icu] The given character is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if the character has no case folding equivalent, the character itself is returned.

This function only returns the simple, single-code point case mapping. Full case mappings should be used whenever possible because they produce better results by working on whole strings. They can map to a result string with a different length as appropriate. Full case mappings are applied by the case mapping functions that take String parameters rather than code points (int). See also the User Guide chapter on C/POSIX migration: http://www.icu-project.org/userguide/posix.html#case_mappings

Parameters
ch the character to be converted
defaultmapping Indicates whether the default mappings defined in CaseFolding.txt are to be used, otherwise the mappings for dotted I and dotless i marked with 'T' in CaseFolding.txt are included.
Returns
  • the case folding equivalent of the character, if any; otherwise the character itself.

public static int foldCase (int ch, int options)

[icu] The given character is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if the character has no case folding equivalent, the character itself is returned.

This function only returns the simple, single-code point case mapping. Full case mappings should be used whenever possible because they produce better results by working on whole strings. They can map to a result string with a different length as appropriate. Full case mappings are applied by the case mapping functions that take String parameters rather than code points (int). See also the User Guide chapter on C/POSIX migration: http://www.icu-project.org/userguide/posix.html#case_mappings

Parameters
ch the character to be converted
options A bit set for special processing. Currently the recognised options are FOLD_CASE_EXCLUDE_SPECIAL_I and FOLD_CASE_DEFAULT
Returns
  • the case folding equivalent of the character, if any; otherwise the character itself.

public static String foldCase (String str, int options)

[icu] The given string is mapped to its case folding equivalent according to UnicodeData.txt and CaseFolding.txt; if any character has no case folding equivalent, the character itself is returned. "Full", multiple-code point case folding mappings are returned here. For "simple" single-code point mappings use the API foldCase(int ch, boolean defaultmapping).

Parameters
str the String to be converted
options A bit set for special processing. Currently the recognised options are FOLD_CASE_EXCLUDE_SPECIAL_I and FOLD_CASE_DEFAULT
Returns
  • the case folding equivalent of the character, if any; otherwise the character itself.

public static char forDigit (int digit, int radix)

Provide the java.lang.Character forDigit API, for convenience.

Parameters
digit
radix

public static VersionInfo getAge (int ch)

[icu] Returns the "age" of the code point.

The "age" is the Unicode version when the code point was first designated (as a non-character or for Private Use) or assigned a character.

This can be useful to avoid emitting code points to receiving processes that do not accept newer characters.

The data is from the UCD file DerivedAge.txt.

Parameters
ch The code point.
Returns
  • the Unicode version number

public static int getBidiPairedBracket (int c)

[icu] Maps the specified character to its paired bracket character. For Bidi_Paired_Bracket_Type!=None, this is the same as getMirror(int). Otherwise c itself is returned. See http://www.unicode.org/reports/tr9/

Parameters
c the code point to be mapped
Returns
  • the paired bracket code point, or c itself if there is no such mapping (Bidi_Paired_Bracket_Type=None)

public static int getCharFromExtendedName (String name)

[icu]

Find a Unicode character by either its name and return its code point value. All Unicode names are in uppercase. Extended names are all lowercase except for numbers and are contained within angle brackets. The names are searched in the following order

  • Most current Unicode name if there is any
  • Unicode 1.0 name if there is any
  • Extended name in the form of "<codepoint_type-codepoint_hex_digits>". E.g. <noncharacter-FFFE>
Note calling any methods related to code point names, e.g. get*Name*() incurs a one-time initialisation cost to construct the name tables.

Parameters
name codepoint name
Returns
  • code point associated with the name or -1 if the name is not found.

public static int getCharFromName (String name)

[icu]

Finds a Unicode code point by its most current Unicode name and return its code point value. All Unicode names are in uppercase. Note calling any methods related to code point names, e.g. get*Name*() incurs a one-time initialisation cost to construct the name tables.

Parameters
name most current Unicode character name whose code point is to be returned
Returns
  • code point or -1 if name is not found

public static int getCharFromNameAlias (String name)

[icu]

Find a Unicode character by its corrected name alias and return its code point value. All Unicode names are in uppercase. Note calling any methods related to code point names, e.g. get*Name*() incurs a one-time initialisation cost to construct the name tables.

Parameters
name Unicode name alias whose code point is to be returned
Returns
  • code point or -1 if name is not found

public static int getCodePoint (char char16)

[icu] Returns the code point corresponding to the BMP code point.

Parameters
char16 the BMP code point
Returns
  • code point if argument is a valid character.
Throws
IllegalArgumentException thrown when char16 is not a valid code point

public static int getCodePoint (char lead, char trail)

[icu] Returns a code point corresponding to the two surrogate code units.

Parameters
lead the lead char
trail the trail char
Returns
  • code point if surrogate characters are valid.
Throws
IllegalArgumentException thrown when the code units do not form a valid code point

public static int getCombiningClass (int ch)

[icu] Returns the combining class of the argument codepoint

Parameters
ch code point whose combining is to be retrieved
Returns
  • the combining class of the codepoint

public static int getDirection (int ch)

[icu] Returns the Bidirection property of a code point. For example, 0x0041 (letter A) has the LEFT_TO_RIGHT directional property.
Result returned belongs to the interface UCharacterDirection

Parameters
ch the code point to be determined its direction
Returns
  • direction constant from UCharacterDirection.

public static byte getDirectionality (int cp)

Equivalent to the getDirectionality(char) method, for convenience. Returns a byte representing the directionality of the character. [icu] Note: Unlike getDirectionality(char), this returns DIRECTIONALITY_LEFT_TO_RIGHT for undefined or out-of-bounds characters. [icu] Note: The return value must be tested using the constants defined in ERROR(/UCharacterDirection) and its interface UCharacterEnums.ECharacterDirection since the values are different from the ones defined by java.lang.Character.

Parameters
cp the code point to check
Returns
  • the directionality of the code point

public static String getExtendedName (int ch)

[icu] Returns a name for a valid codepoint. Unlike, getName(int) and getName1_0(int), this method will return a name even for codepoints that are not assigned a name in UnicodeData.txt.

The names are returned in the following order.

  • Most current Unicode name if there is any
  • Unicode 1.0 name if there is any
  • Extended name in the form of "<codepoint_type-codepoint_hex_digits>". E.g., <noncharacter-fffe>
Note calling any methods related to code point names, e.g. get*Name*() incurs a one-time initialisation cost to construct the name tables.

Parameters
ch the code point for which to get the name
Returns
  • a name for the argument codepoint

public static ValueIterator getExtendedNameIterator ()

[icu]

Returns an iterator for character names, iterating over codepoints.

This API only gets the iterator for the extended names. For modern, most up-to-date Unicode names use getNameIterator() or for older 1.0 Unicode names use get1_0NameIterator().

Example of use:

 ValueIterator iterator = UCharacter.getExtendedNameIterator();
 ValueIterator.Element element = new ValueIterator.Element();
 while (iterator.next(element)) {
     System.out.println("Codepoint \\u" +
                        Integer.toHexString(element.codepoint) +
                        " has the name " + (String)element.value);
 }
 

The maximal range which the name iterator iterates is from

Returns
  • an iterator

public static int getHanNumericValue (int ch)

[icu] Returns the numeric value of a Han character.

This returns the value of Han 'numeric' code points, including those for zero, ten, hundred, thousand, ten thousand, and hundred million. This includes both the standard and 'checkwriting' characters, the 'big circle' zero character, and the standard zero character.

Note: The Unicode Standard has numeric values for more Han characters recognized by this method (see getNumericValue(int) and the UCD file DerivedNumericValues.txt), and a NumberFormat can be used with a Chinese NumberingSystem.

Parameters
ch code point to query
Returns
  • value if it is a Han 'numeric character,' otherwise return -1.

public static int getIntPropertyMaxValue (int type)

[icu] Returns the maximum value for an integer/binary Unicode property. Can be used together with UCharacter.getIntPropertyMinValue(int) to allocate arrays of android.icu.text.UnicodeSet or similar. Examples for min/max values (for Unicode 3.2):

  • UProperty.BIDI_CLASS: 0/18 (UCharacterDirection.LEFT_TO_RIGHT/UCharacterDirection.BOUNDARY_NEUTRAL)
  • UProperty.SCRIPT: 0/45 (UScript.COMMON/UScript.TAGBANWA)
  • UProperty.IDEOGRAPHIC: 0/1 (false/true)
For undefined UProperty constant values, min/max values will be 0/-1.

Parameters
type UProperty selector constant, identifies which binary property to check. Must be UProperty.BINARY_START <= type < UProperty.BINARY_LIMIT or UProperty.INT_START <= type < UProperty.INT_LIMIT.
Returns
  • Maximum value returned by u_getIntPropertyValue for a Unicode property. <= 0 if the property selector 'type' is out of range.

public static int getIntPropertyMinValue (int type)

[icu] Returns the minimum value for an integer/binary Unicode property type. Can be used together with UCharacter.getIntPropertyMaxValue(int) to allocate arrays of android.icu.text.UnicodeSet or similar.

Parameters
type UProperty selector constant, identifies which binary property to check. Must be UProperty.BINARY_START <= type < UProperty.BINARY_LIMIT or UProperty.INT_START <= type < UProperty.INT_LIMIT.
Returns
  • Minimum value returned by UCharacter.getIntPropertyValue(int) for a Unicode property. 0 if the property selector 'type' is out of range.

public static int getIntPropertyValue (int ch, int type)

[icu]

Returns the property value for an Unicode property type of a code point. Also returns binary and mask property values.

Unicode, especially in version 3.2, defines many more properties than the original set in UnicodeData.txt.

The properties APIs are intended to reflect Unicode properties as defined in the Unicode Character Database (UCD) and Unicode Technical Reports (UTR). For details about the properties see http://www.unicode.org/.

For names of Unicode properties see the UCD file PropertyAliases.txt.

 Sample usage:
 int ea = UCharacter.getIntPropertyValue(c, UProperty.EAST_ASIAN_WIDTH);
 int ideo = UCharacter.getIntPropertyValue(c, UProperty.IDEOGRAPHIC);
 boolean b = (ideo == 1) ? true : false;
 

Parameters
ch code point to test.
type UProperty selector constant, identifies which binary property to check. Must be UProperty.BINARY_START <= type < UProperty.BINARY_LIMIT or UProperty.INT_START <= type < UProperty.INT_LIMIT or UProperty.MASK_START <= type < UProperty.MASK_LIMIT.
Returns
  • numeric value that is directly the property value or, for enumerated properties, corresponds to the numeric value of the enumerated constant of the respective property value enumeration type (cast to enum type if necessary). Returns 0 or 1 (for false / true) for binary Unicode properties. Returns a bit-mask for mask properties. Returns 0 if 'type' is out of bounds or if the Unicode version does not have data for the property at all, or not for this code point.

public static int getMirror (int ch)

[icu] Maps the specified code point to a "mirror-image" code point. For code points with the "mirrored" property, implementations sometimes need a "poor man's" mapping to another code point such that the default glyph may serve as the mirror-image of the default glyph of the specified code point.
This is useful for text conversion to and from codepages with visual order, and for displays without glyph selection capabilities.

Parameters
ch code point whose mirror is to be retrieved
Returns
  • another code point that may serve as a mirror-image substitute, or ch itself if there is no such mapping or ch does not have the "mirrored" property

public static String getName (int ch)

[icu] Returns the most current Unicode name of the argument code point, or null if the character is unassigned or outside the range UCharacter.MIN_VALUE and UCharacter.MAX_VALUE or does not have a name.
Note calling any methods related to code point names, e.g. get*Name*() incurs a one-time initialisation cost to construct the name tables.

Parameters
ch the code point for which to get the name
Returns
  • most current Unicode name

public static String getName (String s, String separator)

[icu] Returns the names for each of the characters in a string

Parameters
s string to format
separator string to go between names
Returns
  • string of names

public static String getNameAlias (int ch)

[icu] Returns the corrected name from NameAliases.txt if there is one. Returns null if the character is unassigned or outside the range UCharacter.MIN_VALUE and UCharacter.MAX_VALUE or does not have a name.
Note calling any methods related to code point names, e.g. get*Name*() incurs a one-time initialisation cost to construct the name tables.

Parameters
ch the code point for which to get the name alias
Returns
  • Unicode name alias, or null

public static ValueIterator getNameIterator ()

[icu]

Returns an iterator for character names, iterating over codepoints.

This API only gets the iterator for the modern, most up-to-date Unicode names. For older 1.0 Unicode names use get1_0NameIterator() or for extended names use getExtendedNameIterator().

Example of use:

 ValueIterator iterator = UCharacter.getNameIterator();
 ValueIterator.Element element = new ValueIterator.Element();
 while (iterator.next(element)) {
     System.out.println("Codepoint \\u" +
                        Integer.toHexString(element.codepoint) +
                        " has the name " + (String)element.value);
 }
 

The maximal range which the name iterator iterates is from UCharacter.MIN_VALUE to UCharacter.MAX_VALUE.

Returns
  • an iterator

public static int getNumericValue (int ch)

Returns the numeric value of the code point as a nonnegative integer.
If the code point does not have a numeric value, then -1 is returned.
If the code point has a numeric value that cannot be represented as a nonnegative integer (for example, a fractional value), then -2 is returned.

Parameters
ch the code point to query
Returns
  • the numeric value of the code point, or -1 if it has no numeric value, or -2 if it has a numeric value that cannot be represented as a nonnegative integer

public static int getPropertyEnum (CharSequence propertyAlias)

[icu] Return the UProperty selector for a given property name, as specified in the Unicode database file PropertyAliases.txt. Short, long, and any other variants are recognized. In addition, this function maps the synthetic names "gcm" / "General_Category_Mask" to the property UProperty.GENERAL_CATEGORY_MASK. These names are not in PropertyAliases.txt.

Parameters
propertyAlias the property name to be matched. The name is compared using "loose matching" as described in PropertyAliases.txt.
Returns
  • a UProperty enum.
Throws
IllegalArgumentException thrown if propertyAlias is not recognized.
See Also

public static String getPropertyName (int property, int nameChoice)

[icu] Return the Unicode name for a given property, as given in the Unicode database file PropertyAliases.txt. Most properties have more than one name. The nameChoice determines which one is returned. In addition, this function maps the property UProperty.GENERAL_CATEGORY_MASK to the synthetic names "gcm" / "General_Category_Mask". These names are not in PropertyAliases.txt.

Parameters
property UProperty selector.
nameChoice UProperty.NameChoice selector for which name to get. All properties have a long name. Most have a short name, but some do not. Unicode allows for additional names; if present these will be returned by UProperty.NameChoice.LONG + i, where i=1, 2,...
Returns
  • a name, or null if Unicode explicitly defines no name ("n/a") for a given property/nameChoice. If a given nameChoice throws an exception, then all larger values of nameChoice will throw an exception. If null is returned for a given nameChoice, then other nameChoice values may return non-null results.
Throws
IllegalArgumentException thrown if property or nameChoice are invalid.

public static int getPropertyValueEnum (int property, CharSequence valueAlias)

[icu] Return the property value integer for a given value name, as specified in the Unicode database file PropertyValueAliases.txt. Short, long, and any other variants are recognized. Note: Some of the names in PropertyValueAliases.txt will only be recognized with UProperty.GENERAL_CATEGORY_MASK, not UProperty.GENERAL_CATEGORY. These include: "C" / "Other", "L" / "Letter", "LC" / "Cased_Letter", "M" / "Mark", "N" / "Number", "P" / "Punctuation", "S" / "Symbol", and "Z" / "Separator".

Parameters
property UProperty selector constant. UProperty.INT_START <= property < UProperty.INT_LIMIT or UProperty.BINARY_START <= property < UProperty.BINARY_LIMIT or UProperty.MASK_START < = property < UProperty.MASK_LIMIT. Only these properties can be enumerated.
valueAlias the value name to be matched. The name is compared using "loose matching" as described in PropertyValueAliases.txt.
Returns
  • a value integer. Note: UProperty.GENERAL_CATEGORY values are mask values produced by left-shifting 1 by UCharacter.getType(). This allows grouped categories such as [:L:] to be represented.
Throws
IllegalArgumentException if property is not a valid UProperty selector or valueAlias is not a value of this property
See Also

public static String getPropertyValueName (int property, int value, int nameChoice)

[icu] Return the Unicode name for a given property value, as given in the Unicode database file PropertyValueAliases.txt. Most values have more than one name. The nameChoice determines which one is returned. Note: Some of the names in PropertyValueAliases.txt can only be retrieved using UProperty.GENERAL_CATEGORY_MASK, not UProperty.GENERAL_CATEGORY. These include: "C" / "Other", "L" / "Letter", "LC" / "Cased_Letter", "M" / "Mark", "N" / "Number", "P" / "Punctuation", "S" / "Symbol", and "Z" / "Separator".

Parameters
property UProperty selector constant. UProperty.INT_START <= property < UProperty.INT_LIMIT or UProperty.BINARY_START <= property < UProperty.BINARY_LIMIT or UProperty.MASK_START < = property < UProperty.MASK_LIMIT. If out of range, null is returned.
value selector for a value for the given property. In general, valid values range from 0 up to some maximum. There are a few exceptions: (1.) UProperty.BLOCK values begin at the non-zero value BASIC_LATIN.getID(). (2.) UProperty.CANONICAL_COMBINING_CLASS values are not contiguous and range from 0..240. (3.) UProperty.GENERAL_CATEGORY_MASK values are mask values produced by left-shifting 1 by UCharacter.getType(). This allows grouped categories such as [:L:] to be represented. Mask values are non-contiguous.
nameChoice UProperty.NameChoice selector for which name to get. All values have a long name. Most have a short name, but some do not. Unicode allows for additional names; if present these will be returned by UProperty.NameChoice.LONG + i, where i=1, 2,...
Returns
  • a name, or null if Unicode explicitly defines no name ("n/a") for a given property/value/nameChoice. If a given nameChoice throws an exception, then all larger values of nameChoice will throw an exception. If null is returned for a given nameChoice, then other nameChoice values may return non-null results.
Throws
IllegalArgumentException thrown if property, value, or nameChoice are invalid.

public static int getType (int ch)

Returns a value indicating a code point's Unicode category. Up-to-date Unicode implementation of java.lang.Character.getType() except for the above mentioned code points that had their category changed.
Return results are constants from the interface UCharacterCategory
NOTE: the UCharacterCategory values are not compatible with those returned by java.lang.Character.getType. UCharacterCategory values match the ones used in ICU4C, while java.lang.Character type values, though similar, skip the value 17.

Parameters
ch code point whose type is to be determined
Returns
  • category which is a value of UCharacterCategory

public static RangeValueIterator getTypeIterator ()

[icu]

Returns an iterator for character types, iterating over codepoints.

Example of use:

 RangeValueIterator iterator = UCharacter.getTypeIterator();
 RangeValueIterator.Element element = new RangeValueIterator.Element();
 while (iterator.next(element)) {
     System.out.println("Codepoint \\u" +
                        Integer.toHexString(element.start) +
                        " to codepoint \\u" +
                        Integer.toHexString(element.limit - 1) +
                        " has the character type " +
                        element.value);
 }
 

Returns
  • an iterator

public static double getUnicodeNumericValue (int ch)

[icu] Returns the numeric value for a Unicode code point as defined in the Unicode Character Database.

A "double" return type is necessary because some numeric values are fractions, negative, or too large for int.

For characters without any numeric values in the Unicode Character Database, this function will return NO_NUMERIC_VALUE. Note: This is different from the Unicode Standard which specifies NaN as the default value.

API Change: In release 2.2 and prior, this API has a return type int and returns -1 when the argument ch does not have a corresponding numeric value. This has been changed to synch with ICU4C This corresponds to the ICU4C function u_getNumericValue.

Parameters
ch Code point to get the numeric value for.
Returns
  • numeric value of ch, or NO_NUMERIC_VALUE if none is defined.

public static VersionInfo getUnicodeVersion ()

[icu] Returns the version of Unicode data used.

Returns
  • the unicode version number used

public static boolean hasBinaryProperty (int ch, int property)

[icu]

Check a binary Unicode property for a code point.

Unicode, especially in version 3.2, defines many more properties than the original set in UnicodeData.txt.

This API is intended to reflect Unicode properties as defined in the Unicode Character Database (UCD) and Unicode Technical Reports (UTR).

For details about the properties see http://www.unicode.org/.

For names of Unicode properties see the UCD file PropertyAliases.txt.

This API does not check the validity of the codepoint.

Important: If ICU is built with UCD files from Unicode versions below 3.2, then properties marked with "new" are not or not fully available.

Parameters
ch code point to test.
property selector constant from android.icu.lang.UProperty, identifies which binary property to check.
Returns
  • true or false according to the binary Unicode property value for ch. Also false if property is out of bounds or if the Unicode version does not have data for the property at all, or not for this code point.
See Also

public static boolean isBMP (int ch)

[icu] Determines if the code point is in the BMP plane.

Parameters
ch code point to be determined if it is not a supplementary character
Returns
  • true if code point is not a supplementary character

public static boolean isBaseForm (int ch)

[icu] Determines whether the specified code point is of base form. A code point of base form does not graphically combine with preceding characters, and is neither a control nor a format character.

Parameters
ch code point to be determined if it is of base form
Returns
  • true if the code point is of base form

public static boolean isDefined (int ch)

Determines if a code point has a defined meaning in the up-to-date Unicode standard. E.g. supplementary code points though allocated space are not defined in Unicode yet.
Up-to-date Unicode implementation of java.lang.Character.isDefined()

Parameters
ch code point to be determined if it is defined in the most current version of Unicode
Returns
  • true if this code point is defined in unicode

public static boolean isDigit (int ch)

Determines if a code point is a Java digit.
This method observes the semantics of java.lang.Character.isDigit(). It returns true for decimal digits only.
Semantic Change: In release 1.3.1 and prior, this treated numeric letters and other numbers as digits. This has been changed to conform to the java semantics.

Parameters
ch code point to query
Returns
  • true if this code point is a digit

public static boolean isHighSurrogate (char ch)

Parameters
ch the char to check
Returns
  • true if ch is a high (lead) surrogate

public static boolean isISOControl (int ch)

Determines if the specified code point is an ISO control character. A code point is considered to be an ISO control character if it is in the range \u0000 through \u001F or in the range \u007F through \u009F.
Up-to-date Unicode implementation of java.lang.Character.isISOControl()

Parameters
ch code point to determine if it is an ISO control character
Returns
  • true if code point is a ISO control character

public static boolean isIdentifierIgnorable (int ch)

Determines if the specified code point should be regarded as an ignorable character in a Java identifier. A character is Java-identifier-ignorable if it has the general category Cf Formatting Control, or it is a non-Java-whitespace ISO control: U+0000..U+0008, U+000E..U+001B, U+007F..U+009F.
Up-to-date Unicode implementation of java.lang.Character.isIdentifierIgnorable().
See UTR #8.

Note that Unicode just recommends to ignore Cf (format controls).

Parameters
ch code point to be determined if it can be ignored in a Unicode identifier.
Returns
  • true if the code point is ignorable

public static boolean isJavaIdentifierPart (int cp)

Compatibility override of Java method, delegates to java.lang.Character.isJavaIdentifierPart.

Parameters
cp the code point
Returns
  • true if the code point can continue a java identifier.

public static boolean isJavaIdentifierStart (int cp)

Compatibility override of Java method, delegates to java.lang.Character.isJavaIdentifierStart.

Parameters
cp the code point
Returns
  • true if the code point can start a java identifier.

public static boolean isLegal (int ch)

[icu] A code point is illegal if and only if

  • Out of bounds, less than 0 or greater than UCharacter.MAX_VALUE
  • A surrogate value, 0xD800 to 0xDFFF
  • Not-a-character, having the form 0x xxFFFF or 0x xxFFFE
Note: legal does not mean that it is assigned in this version of Unicode.

Parameters
ch code point to determine if it is a legal code point by itself
Returns
  • true if and only if legal.

public static boolean isLegal (String str)

[icu] A string is legal iff all its code points are legal. A code point is illegal if and only if

  • Out of bounds, less than 0 or greater than UCharacter.MAX_VALUE
  • A surrogate value, 0xD800 to 0xDFFF
  • Not-a-character, having the form 0x xxFFFF or 0x xxFFFE
Note: legal does not mean that it is assigned in this version of Unicode.

Parameters
str containing code points to examin
Returns
  • true if and only if legal.

public static boolean isLetter (int ch)

Determines if the specified code point is a letter. Up-to-date Unicode implementation of java.lang.Character.isLetter()

Parameters
ch code point to determine if it is a letter
Returns
  • true if code point is a letter

public static boolean isLetterOrDigit (int ch)

Determines if the specified code point is a letter or digit. [icu] Note: This method, unlike java.lang.Character does not regard the ascii characters 'A' - 'Z' and 'a' - 'z' as digits.

Parameters
ch code point to determine if it is a letter or a digit
Returns
  • true if code point is a letter or a digit

public static boolean isLowSurrogate (char ch)

Parameters
ch the char to check
Returns
  • true if ch is a low (trail) surrogate

public static boolean isLowerCase (int ch)

Determines if the specified code point is a lowercase character. UnicodeData only contains case mappings for code points where they are one-to-one mappings; it also omits information about context-sensitive case mappings.
For more information about Unicode case mapping please refer to the Technical report #21.
Up-to-date Unicode implementation of java.lang.Character.isLowerCase()

Parameters
ch code point to determine if it is in lowercase
Returns
  • true if code point is a lowercase character

public static boolean isMirrored (int ch)

Determines whether the code point has the "mirrored" property. This property is set for characters that are commonly used in Right-To-Left contexts and need to be displayed with a "mirrored" glyph.

Parameters
ch code point whose mirror is to be determined
Returns
  • true if the code point has the "mirrored" property

public static boolean isPrintable (int ch)

[icu] Determines whether the specified code point is a printable character according to the Unicode standard.

Parameters
ch code point to be determined if it is printable
Returns
  • true if the code point is a printable character

public static boolean isSpaceChar (int ch)

Determines if the specified code point is a Unicode specified space character, i.e. if code point is in the category Zs, Zl and Zp. Up-to-date Unicode implementation of java.lang.Character.isSpaceChar().

Parameters
ch code point to determine if it is a space
Returns
  • true if the specified code point is a space character

public static boolean isSupplementary (int ch)

[icu] Determines if the code point is a supplementary character. A code point is a supplementary character if and only if it is greater than SUPPLEMENTARY_MIN_VALUE

Parameters
ch code point to be determined if it is in the supplementary plane
Returns
  • true if code point is a supplementary character

public static boolean isSupplementaryCodePoint (int cp)

Parameters
cp the code point to check
Returns
  • true if cp is a supplementary code point

public static boolean isSurrogatePair (char high, char low)

Parameters
high the high (lead) char
low the low (trail) char
Returns
  • true if high, low form a surrogate pair

public static boolean isTitleCase (int ch)

Determines if the specified code point is a titlecase character. UnicodeData only contains case mappings for code points where they are one-to-one mappings; it also omits information about context-sensitive case mappings.
For more information about Unicode case mapping please refer to the Technical report #21.
Up-to-date Unicode implementation of java.lang.Character.isTitleCase().

Parameters
ch code point to determine if it is in title case
Returns
  • true if the specified code point is a titlecase character

public static boolean isUAlphabetic (int ch)

[icu]

Check if a code point has the Alphabetic Unicode property.

Same as UCharacter.hasBinaryProperty(ch, UProperty.ALPHABETIC).

Different from UCharacter.isLetter(ch)!

Parameters
ch codepoint to be tested

public static boolean isULowercase (int ch)

[icu]

Check if a code point has the Lowercase Unicode property.

Same as UCharacter.hasBinaryProperty(ch, UProperty.LOWERCASE).

This is different from UCharacter.isLowerCase(ch)!

Parameters
ch codepoint to be tested

public static boolean isUUppercase (int ch)

[icu]

Check if a code point has the Uppercase Unicode property.

Same as UCharacter.hasBinaryProperty(ch, UProperty.UPPERCASE).

This is different from UCharacter.isUpperCase(ch)!

Parameters
ch codepoint to be tested

public static boolean isUWhiteSpace (int ch)

[icu]

Check if a code point has the White_Space Unicode property.

Same as UCharacter.hasBinaryProperty(ch, UProperty.WHITE_SPACE).

This is different from both UCharacter.isSpace(ch) and UCharacter.isWhitespace(ch)!

Parameters
ch codepoint to be tested

public static boolean isUnicodeIdentifierPart (int ch)

Determines if the specified code point may be any part of a Unicode identifier other than the starting character. A code point may be part of a Unicode identifier if and only if it is one of the following:

  • Lu Uppercase letter
  • Ll Lowercase letter
  • Lt Titlecase letter
  • Lm Modifier letter
  • Lo Other letter
  • Nl Letter number
  • Pc Connecting punctuation character
  • Nd decimal number
  • Mc Spacing combining mark
  • Mn Non-spacing mark
  • Cf formatting code
Up-to-date Unicode implementation of java.lang.Character.isUnicodeIdentifierPart().
See UTR #8.

Parameters
ch code point to determine if is can be part of a Unicode identifier
Returns
  • true if code point is any character belonging a unicode identifier suffix after the first character

public static boolean isUnicodeIdentifierStart (int ch)

Determines if the specified code point is permissible as the first character in a Unicode identifier. A code point may start a Unicode identifier if it is of type either

  • Lu Uppercase letter
  • Ll Lowercase letter
  • Lt Titlecase letter
  • Lm Modifier letter
  • Lo Other letter
  • Nl Letter number
Up-to-date Unicode implementation of java.lang.Character.isUnicodeIdentifierStart().
See UTR #8.

Parameters
ch code point to determine if it can start a Unicode identifier
Returns
  • true if code point is the first character belonging a unicode identifier

public static boolean isUpperCase (int ch)

Determines if the specified code point is an uppercase character. UnicodeData only contains case mappings for code point where they are one-to-one mappings; it also omits information about context-sensitive case mappings.
For language specific case conversion behavior, use toUpperCase(locale, str).
For example, the case conversion for dot-less i and dotted I in Turkish, or for final sigma in Greek. For more information about Unicode case mapping please refer to the Technical report #21.
Up-to-date Unicode implementation of java.lang.Character.isUpperCase().

Parameters
ch code point to determine if it is in uppercase
Returns
  • true if the code point is an uppercase character

public static boolean isValidCodePoint (int cp)

Equivalent to isValidCodePoint(int).

Parameters
cp the code point to check
Returns
  • true if cp is a valid code point

public static boolean isWhitespace (int ch)

Determines if the specified code point is a white space character. A code point is considered to be an whitespace character if and only if it satisfies one of the following criteria:

  • It is a Unicode Separator character (categories "Z" = "Zs" or "Zl" or "Zp"), but is not also a non-breaking space (\u00A0 or \u2007 or \u202F).
  • 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.
This API tries to sync with the semantics of Java's java.lang.Character.isWhitespace(), but it may not return the exact same results because of the Unicode version difference.

Note: Unicode 4.0.1 changed U+200B ZERO WIDTH SPACE from a Space Separator (Zs) to a Format Control (Cf). Since then, isWhitespace(0x200b) returns false. See http://www.unicode.org/versions/Unicode4.0.1/

Parameters
ch code point to determine if it is a white space
Returns
  • true if the specified code point is a white space character

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

Equivalent to the offsetByCodePoints(CharSequence, int, int) method, for convenience. Adjusts the char index by a code point offset.

Parameters
text the characters to check
index the index to adjust
codePointOffset the number of code points by which to offset the index
Returns
  • the adjusted index

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

Equivalent to the offsetByCodePoints(char[], int, int, int, int) method, for convenience. Adjusts the char index by a code point offset.

Parameters
text the characters to check
start the start of the range to check
count the length of the range to check
index the index to adjust
codePointOffset the number of code points by which to offset the index
Returns
  • the adjusted index

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

Same as toChars(int, char[], int). Writes the chars representing the code point into the destination at the given index.

Parameters
cp the code point to convert
dst the destination array into which to put the char(s) representing the code point
dstIndex the index at which to put the first (or only) char
Returns
  • the count of the number of chars written (1 or 2)
Throws
IllegalArgumentException if cp is not a valid code point

public static char[] toChars (int cp)

Same as toChars(int). Returns a char array representing the code point.

Parameters
cp the code point to convert
Returns
  • an array containing the char(s) representing the code point
Throws
IllegalArgumentException if cp is not a valid code point

public static int toCodePoint (char high, char low)

Same as toCodePoint(char, char). Returns the code point represented by the two surrogate code units. This does not check the surrogate pair for validity.

Parameters
high the high (lead) surrogate
low the low (trail) surrogate
Returns
  • the code point formed by the surrogate pair

public static String toLowerCase (String str)

Returns the lowercase version of the argument string. Casing is dependent on the default locale and context-sensitive

Parameters
str source string to be performed on
Returns
  • lowercase version of the argument string

public static int toLowerCase (int ch)

The given code point is mapped to its lowercase equivalent; if the code point has no lowercase equivalent, the code point itself is returned. Up-to-date Unicode implementation of java.lang.Character.toLowerCase()

This function only returns the simple, single-code point case mapping. Full case mappings should be used whenever possible because they produce better results by working on whole strings. They take into account the string context and the language and can map to a result string with a different length as appropriate. Full case mappings are applied by the case mapping functions that take String parameters rather than code points (int). See also the User Guide chapter on C/POSIX migration: http://www.icu-project.org/userguide/posix.html#case_mappings

Parameters
ch code point whose lowercase equivalent is to be retrieved
Returns
  • the lowercase equivalent code point

public static String toLowerCase (ULocale locale, String str)

Returns the lowercase version of the argument string. Casing is dependent on the argument locale and context-sensitive

Parameters
locale which string is to be converted in
str source string to be performed on
Returns
  • lowercase version of the argument string

public static String toLowerCase (Locale locale, String str)

Returns the lowercase version of the argument string. Casing is dependent on the argument locale and context-sensitive

Parameters
locale which string is to be converted in
str source string to be performed on
Returns
  • lowercase version of the argument string

public static String toString (int ch)

Converts argument code point and returns a String object representing the code point's value in UTF-16 format. The result is a string whose length is 1 for BMP code points, 2 for supplementary ones.

Up-to-date Unicode implementation of java.lang.Character.toString().

Parameters
ch code point
Returns
  • string representation of the code point, null if code point is not defined in unicode

public static String toTitleCase (Locale locale, String str, BreakIterator titleIter, int options)

[icu]

Returns the titlecase version of the argument string.

Position for titlecasing is determined by the argument break iterator, hence the user can customize his break iterator for a specialized titlecasing. In this case only the forward iteration needs to be implemented. If the break iterator passed in is null, the default Unicode algorithm will be used to determine the titlecase positions.

Only positions returned by the break iterator will be title cased, character in between the positions will all be in lower case.

Casing is dependent on the argument locale and context-sensitive

Parameters
locale which string is to be converted in
str source string to be performed on
titleIter break iterator to determine the positions in which the character should be title cased.
options bit set to modify the titlecasing operation
Returns
  • lowercase version of the argument string

public static String toTitleCase (ULocale locale, String str, BreakIterator titleIter)

Returns the titlecase version of the argument string.

Position for titlecasing is determined by the argument break iterator, hence the user can customize his break iterator for a specialized titlecasing. In this case only the forward iteration needs to be implemented. If the break iterator passed in is null, the default Unicode algorithm will be used to determine the titlecase positions.

Only positions returned by the break iterator will be title cased, character in between the positions will all be in lower case.

Casing is dependent on the argument locale and context-sensitive

Parameters
locale which string is to be converted in
str source string to be performed on
titleIter break iterator to determine the positions in which the character should be title cased.
Returns
  • lowercase version of the argument string

public static String toTitleCase (String str, BreakIterator breakiter)

Returns the titlecase version of the argument string.

Position for titlecasing is determined by the argument break iterator, hence the user can customize his break iterator for a specialized titlecasing. In this case only the forward iteration needs to be implemented. If the break iterator passed in is null, the default Unicode algorithm will be used to determine the titlecase positions.

Only positions returned by the break iterator will be title cased, character in between the positions will all be in lower case.

Casing is dependent on the default locale and context-sensitive

Parameters
str source string to be performed on
breakiter break iterator to determine the positions in which the character should be title cased.
Returns
  • lowercase version of the argument string

public static String toTitleCase (ULocale locale, String str, BreakIterator titleIter, int options)

Returns the titlecase version of the argument string.

Position for titlecasing is determined by the argument break iterator, hence the user can customize his break iterator for a specialized titlecasing. In this case only the forward iteration needs to be implemented. If the break iterator passed in is null, the default Unicode algorithm will be used to determine the titlecase positions.

Only positions returned by the break iterator will be title cased, character in between the positions will all be in lower case.

Casing is dependent on the argument locale and context-sensitive

Parameters
locale which string is to be converted in
str source string to be performed on
titleIter break iterator to determine the positions in which the character should be title cased.
options bit set to modify the titlecasing operation
Returns
  • lowercase version of the argument string

public static String toTitleCase (Locale locale, String str, BreakIterator breakiter)

Returns the titlecase version of the argument string.

Position for titlecasing is determined by the argument break iterator, hence the user can customize his break iterator for a specialized titlecasing. In this case only the forward iteration needs to be implemented. If the break iterator passed in is null, the default Unicode algorithm will be used to determine the titlecase positions.

Only positions returned by the break iterator will be title cased, character in between the positions will all be in lower case.

Casing is dependent on the argument locale and context-sensitive

Parameters
locale which string is to be converted in
str source string to be performed on
breakiter break iterator to determine the positions in which the character should be title cased.
Returns
  • lowercase version of the argument string

public static int toTitleCase (int ch)

Converts the code point argument to titlecase. If no titlecase is available, the uppercase is returned. If no uppercase is available, the code point itself is returned. Up-to-date Unicode implementation of java.lang.Character.toTitleCase()

This function only returns the simple, single-code point case mapping. Full case mappings should be used whenever possible because they produce better results by working on whole strings. They take into account the string context and the language and can map to a result string with a different length as appropriate. Full case mappings are applied by the case mapping functions that take String parameters rather than code points (int). See also the User Guide chapter on C/POSIX migration: http://www.icu-project.org/userguide/posix.html#case_mappings

Parameters
ch code point whose title case is to be retrieved
Returns
  • titlecase code point

public static String toUpperCase (Locale locale, String str)

Returns the uppercase version of the argument string. Casing is dependent on the argument locale and context-sensitive.

Parameters
locale which string is to be converted in
str source string to be performed on
Returns
  • uppercase version of the argument string

public static String toUpperCase (ULocale locale, String str)

Returns the uppercase version of the argument string. Casing is dependent on the argument locale and context-sensitive.

Parameters
locale which string is to be converted in
str source string to be performed on
Returns
  • uppercase version of the argument string

public static int toUpperCase (int ch)

Converts the character argument to uppercase. If no uppercase is available, the character itself is returned. Up-to-date Unicode implementation of java.lang.Character.toUpperCase()

This function only returns the simple, single-code point case mapping. Full case mappings should be used whenever possible because they produce better results by working on whole strings. They take into account the string context and the language and can map to a result string with a different length as appropriate. Full case mappings are applied by the case mapping functions that take String parameters rather than code points (int). See also the User Guide chapter on C/POSIX migration: http://www.icu-project.org/userguide/posix.html#case_mappings

Parameters
ch code point whose uppercase is to be retrieved
Returns
  • uppercase code point

public static String toUpperCase (String str)

Returns the uppercase version of the argument string. Casing is dependent on the default locale and context-sensitive.

Parameters
str source string to be performed on
Returns
  • uppercase version of the argument string