Class TypeAsSynonymFilter
- 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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- org.apache.lucene.analysis.miscellaneous.TypeAsSynonymFilter
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public final class TypeAsSynonymFilter extends TokenFilter
Adds theTypeAttribute.type()
as a synonym, i.e. another token at the same position, optionally with a specified prefix prepended.
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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 private PositionIncrementAttribute
posIncrAtt
private java.lang.String
prefix
(package private) AttributeSource.State
savedToken
private CharTermAttribute
termAtt
private TypeAttribute
typeAtt
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Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
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Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
Constructors Constructor Description TypeAsSynonymFilter(TokenStream input)
TypeAsSynonymFilter(TokenStream input, java.lang.String prefix)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
incrementToken()
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
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Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end
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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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termAtt
private final CharTermAttribute termAtt
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typeAtt
private final TypeAttribute typeAtt
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posIncrAtt
private final PositionIncrementAttribute posIncrAtt
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prefix
private final java.lang.String prefix
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savedToken
AttributeSource.State savedToken
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Constructor Detail
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TypeAsSynonymFilter
public TypeAsSynonymFilter(TokenStream input)
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TypeAsSynonymFilter
public TypeAsSynonymFilter(TokenStream input, java.lang.String prefix)
- Parameters:
input
- input tokenstreamprefix
- Prepend this string to every token type emitted as token text. If null, nothing will be prepended.
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Method Detail
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incrementToken
public boolean incrementToken() throws java.io.IOException
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:
java.io.IOException
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reset
public void reset() throws java.io.IOException
Description copied from class:TokenFilter
This 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.,Tokenizer
will throwIllegalStateException
on 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:
reset
in classTokenFilter
- Throws:
java.io.IOException
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