org.nineml.coffeegrinder.tokens

Class CharacterSet

java.lang.Object

org.nineml.coffeegrinder.tokens.CharacterSet

public class CharacterSet
extends java.lang.Object

A class that represents a range of Unicode characters.

Ranges can be constructed from a literal string, from a range of Unicode codepoints, or via Unicode character classes.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj) Tests for the equality of two CharacterSet objects.
java.lang.String	getCharacters() What characters are in the set?
int	getRangeFrom() Where does the range begin?
int	getRangeTo() Where does the range end?
java.lang.String	getUnicodeCharacterClass() What is the Unicode character class?
boolean	isRange() Does this character set represent a range of Unicode code points?
boolean	isSetOfCharacters() Does this character set represent a specific set of characters?
boolean	isUnicodeCharacterClass() Does this character set represent a Unicode character class?
static CharacterSet	literal(java.lang.String literal) Construct a character set containing each of the characters in the literal string.
boolean	matches(int codepoint) Test if a code point occurs in the set.
static CharacterSet	range(int first, int last) Construct a character set containing each of the characters in the specified range, inclusive.
java.lang.String	toString()
static CharacterSet	unicodeClass(java.lang.String charClass) Construct a character set representing the specified Unicode character class.

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

isRange

public boolean isRange()

Does this character set represent a range of Unicode code points?

Returns:

true, if this character set is a range.

getRangeFrom

public int getRangeFrom()

Where does the range begin?

Ranges are inclusive. There result of this method is undefined if isRange() returns false.

Returns:

the first character in the range

getRangeTo

public int getRangeTo()

Where does the range end?

Ranges are inclusive. There result of this method is undefined if isRange() returns false.

Returns:

the last character in the range

isSetOfCharacters

public boolean isSetOfCharacters()

Does this character set represent a specific set of characters?

Returns:

true, if this character set is a specific set of characters.

getCharacters

public java.lang.String getCharacters()

What characters are in the set?

If this character set represents a set of characters, this method returns them as a string. Otherwise, it returns null.

Returns:

the set of characters as a string

isUnicodeCharacterClass

public boolean isUnicodeCharacterClass()

Does this character set represent a Unicode character class?

Returns:

true, if this character set is a Unicode character class

getUnicodeCharacterClass

public java.lang.String getUnicodeCharacterClass()

What is the Unicode character class?

Returns the one or two character string that defines the character class. Returns null if this character set does not represent a Unicode character class.

Returns:

the character class

literal

public static CharacterSet literal(java.lang.String literal)

Construct a character set containing each of the characters in the literal string.

Parameters:

literal - The string of characters.

Returns:

A character set that will match any of those characters.

Throws:

java.lang.NullPointerException - if the literal is null.

java.lang.IllegalArgumentException - if the literal is the empty string.

range

public static CharacterSet range(int first,
                                 int last)

Construct a character set containing each of the characters in the specified range, inclusive.

Parameters:

first - The first codepoint.

last - The last codepoint.

Returns:

A character set that will match each of those characters.

Throws:

java.lang.IllegalArgumentException - if the range is invalid.

unicodeClass

public static CharacterSet unicodeClass(java.lang.String charClass)

Construct a character set representing the specified Unicode character class.

Parameters:

charClass - The character class, for example "L", or "Nd".

Returns:

A character set that will match characters in that class.

Throws:

java.lang.NullPointerException - if the charClass is null.

java.lang.IllegalArgumentException - if the charClass is less than 1 or more than 2 characters long.

equals

public boolean equals(java.lang.Object obj)

Tests for the equality of two CharacterSet objects.

Two CharacterSet objects are equal only if they identify the same characters expressed in the same way. A set created from the literal "0123456789" is not equal to a set created from the range '0' to '9'.

Overrides:

equals in class java.lang.Object

Parameters:

obj - A CharacterSet to test for equality against.

Returns:

true if and only if the character set provided identifies the same range of characters.

matches

public boolean matches(int codepoint)

Test if a code point occurs in the set.

Parameters:

codepoint - The Unicode codepoint to test.

Returns:

true if and only if the codepoint is in the set.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object