Class LimitTokenPositionFilter
- 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.LimitTokenPositionFilter
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class LimitTokenPositionFilter extends TokenFilter
This TokenFilter limits its emitted tokens to those with positions that are not greater than the configured limit.By default, this filter ignores any tokens in the wrapped
TokenStream
once the limit has been exceeded, which can result inreset()
being called prior toincrementToken()
returningfalse
. For mostTokenStream
implementations this should be acceptable, and faster then consuming the full stream. If you are wrapping aTokenStream
which requires that the full stream of tokens be exhausted in order to function properly, use theconsumeAllTokens
option.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.AttributeFactory, AttributeSource.State
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Constructor Summary
Constructors Constructor Description LimitTokenPositionFilter(TokenStream in, int maxTokenPosition)
Build a filter that only accepts tokens up to and including the given maximum position.LimitTokenPositionFilter(TokenStream in, int maxTokenPosition, boolean consumeAllTokens)
Build a filter that limits the maximum position of tokens to emit.
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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, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
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Constructor Detail
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LimitTokenPositionFilter
public LimitTokenPositionFilter(TokenStream in, int maxTokenPosition)
Build a filter that only accepts tokens up to and including the given maximum position. This filter will not consume any tokens with position greater than the maxTokenPosition limit.- Parameters:
in
- the stream to wrapmaxTokenPosition
- max position of tokens to produce (1st token always has position 1)- See Also:
LimitTokenPositionFilter(TokenStream,int,boolean)
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LimitTokenPositionFilter
public LimitTokenPositionFilter(TokenStream in, int maxTokenPosition, boolean consumeAllTokens)
Build a filter that limits the maximum position of tokens to emit.- Parameters:
in
- the stream to wrapmaxTokenPosition
- max position of tokens to produce (1st token always has position 1)consumeAllTokens
- whether all tokens from the wrapped input stream must be consumed even if maxTokenPosition is exceeded.
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Method Detail
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incrementToken
public boolean incrementToken() throws 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:
IOException
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reset
public void reset() throws 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:
IOException
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