Class ConditionalTokenFilter
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
- Direct Known Subclasses:
ProtectedTermFilter
To use, implement the shouldFilter()
method. If it returns true
, then calling
incrementToken()
will use the wrapped TokenFilter(s) to make changes to the tokenstream.
If it returns false
, then the wrapped filter(s) will be skipped.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate final class
private static enum
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate boolean
private AttributeSource.State
private final TokenStream
private int
private AttributeSource.State
private boolean
private boolean
private final PositionIncrementAttribute
Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
ConditionalTokenFilter
(TokenStream input, Function<TokenStream, TokenStream> inputFactory) Create a new ConditionalTokenFilter -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Releases resources associated with this stream.void
end()
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API).private boolean
final boolean
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()
.protected abstract boolean
Whether or not to execute the wrapped TokenFilter(s) for the current tokenMethods inherited from class org.apache.lucene.analysis.TokenFilter
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
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Field Details
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delegate
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state
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lastTokenFiltered
private boolean lastTokenFiltered -
bufferedState
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exhausted
private boolean exhausted -
adjustPosition
private boolean adjustPosition -
endState
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endOffset
private int endOffset -
posIncAtt
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Constructor Details
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ConditionalTokenFilter
Create a new ConditionalTokenFilter- Parameters:
input
- the input TokenStreaminputFactory
- a factory function to create the wrapped filter(s)
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Method Details
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shouldFilter
Whether or not to execute the wrapped TokenFilter(s) for the current token- Throws:
IOException
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reset
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:
IOException
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end
Description copied from class:TokenFilter
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API). 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:
end
in classTokenFilter
- Throws:
IOException
- If an I/O error occurs
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close
Description copied from class:TokenFilter
Releases 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.,Tokenizer
will throwIllegalStateException
on 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:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Overrides:
close
in classTokenFilter
- Throws:
IOException
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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
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endDelegating
- Throws:
IOException
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