Class TokenFilter
- java.lang.Object
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- org.apache.lucene.util.AttributeSource
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- org.apache.lucene.analysis.TokenStream
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- org.apache.lucene.analysis.TokenFilter
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- All Implemented Interfaces:
Closeable,AutoCloseable,Unwrappable<TokenStream>
- Direct Known Subclasses:
CachingTokenFilter,FilteringTokenFilter,GraphTokenFilter,LowerCaseFilter
public abstract class TokenFilter extends TokenStream implements Unwrappable<TokenStream>
A TokenFilter is a TokenStream whose input is another TokenStream.This is an abstract class; subclasses must override
TokenStream.incrementToken().- See Also:
TokenStream
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
Fields Modifier and Type Field Description protected TokenStreaminputThe source of tokens for this filter.-
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
Constructors Modifier Constructor Description protectedTokenFilter(TokenStream input)Construct a token stream filtering the given input.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclose()Releases resources associated with this stream.voidend()This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()returnedfalse(using the newTokenStreamAPI).voidreset()This method is called by a consumer before it begins consumption usingTokenStream.incrementToken().TokenStreamunwrap()Unwraps this instance-
Methods inherited from class org.apache.lucene.analysis.TokenStream
incrementToken
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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
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Field Detail
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input
protected final TokenStream input
The source of tokens for this filter.
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Constructor Detail
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TokenFilter
protected TokenFilter(TokenStream input)
Construct a token stream filtering the given input.
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Method Detail
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end
public void end() throws IOExceptionThis method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()returnedfalse(using the newTokenStreamAPI). Streams implementing the old API should upgrade to use this feature.This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but a WhitespaceTokenizer was used.
Additionally any skipped positions (such as those removed by a stopfilter) can be applied to the position increment, or any adjustment of other attributes where the end-of-stream value may be important.
If you override this method, always call
super.end().NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.end()first when overriding this method.- Overrides:
endin classTokenStream- Throws:
IOException- If an I/O error occurs
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close
public void close() throws IOExceptionReleases resources associated with this stream.If you override this method, always call
super.close(), otherwise some internal state will not be correctly reset (e.g.,Tokenizerwill throwIllegalStateExceptionon reuse).NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.close()when overriding this method.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classTokenStream- Throws:
IOException
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reset
public void reset() throws IOExceptionThis method is called by a consumer before it begins consumption usingTokenStream.incrementToken().Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.
If you override this method, always call
super.reset(), otherwise some internal state will not be correctly reset (e.g.,Tokenizerwill throwIllegalStateExceptionon further usage).NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.reset()when overriding this method.- Overrides:
resetin classTokenStream- Throws:
IOException
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unwrap
public TokenStream unwrap()
Description copied from interface:UnwrappableUnwraps this instance- Specified by:
unwrapin interfaceUnwrappable<TokenStream>
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