org.apache.sis.util

Class Characters.Filter

Object

Character.Subset

Characters.Filter

Enclosing class:

Characters

public static class Characters.Filter
extends Character.Subset

Subsets of Unicode characters identified by their general category. The categories are identified by constants defined in the Character class, like LOWERCASE_LETTER, UPPERCASE_LETTER, DECIMAL_DIGIT_NUMBER and SPACE_SEPARATOR.

An instance of this class can be obtained from an enumeration of character types using the for­Types(byte[]) method, or using one of the constants predefined in this class. Then, Unicode characters can be tested for inclusion in the subset by calling the contains(int) method.

Relationship with international standards

ISO 19162:2015 §B.5.2 recommends to ignore spaces, case and the following characters when comparing two identified object names: “_” (underscore), “-” (minus sign), “/” (solidus), “(” (left parenthesis) and “)” (right parenthesis). The same specification also limits the set of valid characters in a name to the following (§6.3.1):

A-Z a-z 0-9 _ [ ] ( ) { } < = > . , : ; + - (space) % & ' " * ^ / \ ? | °

Note: SIS does not enforce this restriction in its programmatic API, but may perform some character substitutions at Well Known Text (WKT) formatting time.

If we take only the characters in the above list which are valid in a Unicode identifier and remove the characters that ISO 19162 recommends to ignore, the only characters left are letters and digits.

Since:

0.3

See Also:

Character.Subset, Character.get­Type(int), WKT 2 specification §B.5

Defined in the sis-utility module

Field Summary

Fields

Modifier and Type	Field and Description
static Characters.Filter	LETTERS_AND_DIGITS The subset of all characters for which Character.is­Letter­Or­Digit(int) returns true.
static Characters.Filter	UNICODE_IDENTIFIER The subset of all characters for which Character.is­Unicode­Identifier­Part(int) returns true, excluding ignorable characters.

Method Summary

Modifier and Type	Method and Description
boolean	contains(int codePoint) Returns true if this subset contains the given Unicode character.
boolean	containsType(int type) Returns true if this subset contains the characters of the given type.
static Characters.Filter	forTypes(byte... types) Returns a subset representing the union of all Unicode characters of the given types.

Methods inherited from class Character.Subset

equals, hash­Code, to­String

Methods inherited from class Object

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

Field Detail

LETTERS_AND_DIGITS

public static final Characters.Filter LETTERS_AND_DIGITS

The subset of all characters for which Character.is­Letter­Or­Digit(int) returns true. This subset includes the following general categories:

Character.LOWERCASE_LETTER, UPPERCASE_LETTER, TITLECASE_LETTER, MODIFIER_LETTER, OTHER_LETTER and DECIMAL_DIGIT_NUMBER.

SIS uses this filter when comparing two identified object names. See the Relationship with international standards section in this class javadoc for more information.

See Also:

Abstract­Identified­Object.is­Heuristic­Match­For­Name(String), Citations.identifier­Matches(Citation, String)

UNICODE_IDENTIFIER

public static final Characters.Filter UNICODE_IDENTIFIER

The subset of all characters for which Character.is­Unicode­Identifier­Part(int) returns true, excluding ignorable characters. This subset includes all the LETTERS_AND_DIGITS categories with the addition of the following ones:

Character.LETTER_NUMBER, CONNECTOR_PUNCTUATION, NON_SPACING_MARK and COMBINING_SPACING_MARK.

Method Detail

contains

public boolean contains(int codePoint)

Returns true if this subset contains the given Unicode character.

Parameters:

code­Point - the Unicode character, as a code point value.

Returns:

true if this subset contains the given character.

containsType

public final boolean containsType(int type)

Returns true if this subset contains the characters of the given type. The given type shall be one of the Character constants like LOWERCASE_LETTER, UPPERCASE_LETTER, DECIMAL_DIGIT_NUMBER or SPACE_SEPARATOR.

Parameters:

type - one of the Character constants.

Returns:

true if this subset contains the characters of the given type.

See Also:

Character.get­Type(int)

forTypes

public static Characters.Filter forTypes(byte... types)

Returns a subset representing the union of all Unicode characters of the given types.

Parameters:

types - the character types, as Character constants.

Returns:

the subset of Unicode characters of the given type.

See Also:

Character.LOWERCASE_LETTER, Character.UPPERCASE_LETTER, Character.DECIMAL_DIGIT_NUMBER, Character.SPACE_SEPARATOR