Added in API level 24

UnicodeFilter

---

Kotlin |Java

abstract class UnicodeFilter : UnicodeMatcher

kotlin.Any
↳	android.icu.text.UnicodeFilter

Known Direct Subclasses UnicodeSet UnicodeSet A mutable set of Unicode characters and multicharacter strings.

UnicodeFilter defines a protocol for selecting a subset of the full range (U+0000 to U+FFFF) of Unicode characters. Currently, filters are used in conjunction with classes like android.icu.text.Transliterator to only process selected characters through a transformation.

Summary

Inherited constants

From class UnicodeMatcher Char ETHER The character at index i, where i < contextStart || i >= contextLimit, is ETHER. This allows explicit matching by rules and UnicodeSets of text outside the context. In traditional terms, this allows anchoring at the start and/or end. Int U_MATCH Constant returned by matches() indicating a complete match between the text and this matcher. For an incremental variable-length match, this value is returned if the given text matches, and it is known that additional characters would not alter the extent of the match. Int U_MISMATCH Constant returned by matches() indicating a mismatch between the text and this matcher. The text contains a character which does not match, or the text does not contain all desired characters for a non-incremental match. Int U_PARTIAL_MATCH Constant returned by matches() indicating a partial match between the text and this matcher. This value is only returned for incremental match operations. All characters of the text match, but more characters are required for a complete match. Alternatively, for variable-length matchers, all characters of the text match, and if more characters were supplied at limit, they might also match.

Public methods
abstract Boolean	contains(c: Int) Returns true for characters that are in the selected subset.
open Int	matches(text: Replaceable!, offset: IntArray!, limit: Int, incremental: Boolean) Default implementation of UnicodeMatcher::matches() for Unicode filters.

Inherited functions

From class UnicodeMatcher Unit addMatchSetTo(toUnionTo: UnicodeSet!) Union the set of all characters that may be matched by this object into the given set. Boolean matchesIndexValue(v: Int) Returns true if this matcher will match a character c, where c & 0xFF == v, at offset, in the forward direction (with limit > offset). This is used by RuleBasedTransliterator for indexing. Note: This API uses an int even though the value will be restricted to 8 bits in order to avoid complications with signedness (bytes convert to ints in the range -128..127). String! toPattern(escapeUnprintable: Boolean) Returns a string representation of this matcher. If the result of calling this function is passed to the appropriate parser, it will produce another matcher that is equal to this one.

Public methods

contains

Added in API level 24

abstract fun contains(c: Int): Boolean

Returns true for characters that are in the selected subset. In other words, if a character is to be filtered, then contains() returns false.

matches

Added in API level 24

open fun matches(
    text: Replaceable!, 
    offset: IntArray!, 
    limit: Int, 
    incremental: Boolean
): Int

Default implementation of UnicodeMatcher::matches() for Unicode filters. Matches a single 16-bit code unit at offset.

Parameters
text	Replaceable!: the text to be matched
offset	IntArray!: on input, the index into text at which to begin matching. On output, the limit of the matched text. The number of matched characters is the output value of offset minus the input value. Offset should always point to the HIGH SURROGATE (leading code unit) of a pair of surrogates, both on entry and upon return.
limit	Int: the limit index of text to be matched. Greater than offset for a forward direction match, less than offset for a backward direction match. The last character to be considered for matching will be text.charAt(limit-1) in the forward direction or text.charAt(limit+1) in the backward direction.
incremental	Boolean: if true, then assume further characters may be inserted at limit and check for partial matching. Otherwise assume the text as given is complete.

Return
Int	a match degree value indicating a full match, a partial match, or a mismatch. If incremental is false then U_PARTIAL_MATCH should never be returned.