com.ibm.icu.text
Class UnicodeFilter

java.lang.Object
  com.ibm.icu.text.UnicodeFilter

All Implemented Interfaces:

UnicodeMatcher

Direct Known Subclasses:

UnicodeSet

public abstract class UnicodeFilter
extends Object
implements UnicodeMatcher

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 Transliterator to only process selected characters through a transformation.

Status:

Stable ICU 2.0.

Field Summary

Fields inherited from interface com.ibm.icu.text.UnicodeMatcher

ETHER, U_MATCH, U_MISMATCH, U_PARTIAL_MATCH

Constructor Summary

protected

UnicodeFilter() Deprecated. This API is ICU internal only.

Method Summary

abstract boolean	contains(int c) Returns true for characters that are in the selected subset.
int	matches(Replaceable text, int[] offset, int limit, boolean incremental) Default implementation of UnicodeMatcher::matches() for Unicode filters.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.ibm.icu.text.UnicodeMatcher

addMatchSetTo, matchesIndexValue, toPattern

Constructor Detail

UnicodeFilter

protected UnicodeFilter()

Deprecated. This API is ICU internal only.

(This should not be here; it is declared to make CheckTags happy. Java inserts a synthetic constructor and CheckTags can't tell that it's synthetic.)

Status:

Internal. This API is ICU internal only.

Method Detail

contains

public abstract boolean contains(int c)

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

Status:

Stable ICU 2.0.

matches

public int matches(Replaceable text,
                   int[] offset,
                   int limit,
                   boolean incremental)

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

Specified by:

matches in interface UnicodeMatcher

Parameters:

text - the text to be matched

offset - 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 - 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 - if TRUE, then assume further characters may be inserted at limit and check for partial matching. Otherwise assume the text as given is complete.

Returns:

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.

Status:

Stable ICU 2.0.