Class TurkishLowerCaseFilter
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
Turkish and Azeri have unique casing behavior for some characters. This filter applies Turkish lowercase rules. For more information, see http://en.wikipedia.org/wiki/Turkish_dotted_and_dotless_I
-
Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final int
private static final int
private static final int
private static final int
private final CharTermAttribute
Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
-
Constructor Summary
ConstructorsConstructorDescriptionCreate a new TurkishLowerCaseFilter, that normalizes Turkish token text to lower case. -
Method Summary
Modifier and TypeMethodDescriptionprivate int
delete
(char[] s, int pos, int len) delete a character in-place.final boolean
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.private boolean
isBeforeDot
(char[] s, int pos, int len) lookahead for a combining dot above.Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end, reset, unwrap
Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
-
Field Details
-
LATIN_CAPITAL_LETTER_I
private static final int LATIN_CAPITAL_LETTER_I- See Also:
-
LATIN_SMALL_LETTER_I
private static final int LATIN_SMALL_LETTER_I- See Also:
-
LATIN_SMALL_LETTER_DOTLESS_I
private static final int LATIN_SMALL_LETTER_DOTLESS_I- See Also:
-
COMBINING_DOT_ABOVE
private static final int COMBINING_DOT_ABOVE- See Also:
-
termAtt
-
-
Constructor Details
-
TurkishLowerCaseFilter
Create a new TurkishLowerCaseFilter, that normalizes Turkish token text to lower case.- Parameters:
in
- TokenStream to filter
-
-
Method Details
-
incrementToken
Description copied from class:TokenStream
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriateAttributeImpl
s with the attributes of the next token.The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use
AttributeSource.captureState()
to create a copy of the current attribute state.This method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to
AttributeSource.addAttribute(Class)
andAttributeSource.getAttribute(Class)
, references to allAttributeImpl
s that this stream uses should be retrieved during instantiation.To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in
TokenStream.incrementToken()
.- Specified by:
incrementToken
in classTokenStream
- Returns:
- false for end of stream; true otherwise
- Throws:
IOException
-
isBeforeDot
private boolean isBeforeDot(char[] s, int pos, int len) lookahead for a combining dot above. other NSMs may be in between. -
delete
private int delete(char[] s, int pos, int len) delete a character in-place. rarely happens, only if COMBINING_DOT_ABOVE is found after an i
-