Class PositionFilter
- 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.position.PositionFilter
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class PositionFilter extends TokenFilter
Set the positionIncrement of all tokens to the "positionIncrement", except the first return token which retains its original positionIncrement value. The default positionIncrement value is zero.
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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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Field Summary
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Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
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Constructor Summary
Constructors Constructor Description PositionFilter(TokenStream input)
Constructs a PositionFilter that assigns a position increment of zero to all but the first token from the given input stream.PositionFilter(TokenStream input, int positionIncrement)
Constructs a PositionFilter that assigns the given position increment to all but the first token from the given input stream.
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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()
Reset the filter as well as the input TokenStream.-
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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PositionFilter
public PositionFilter(TokenStream input)
Constructs a PositionFilter that assigns a position increment of zero to all but the first token from the given input stream.- Parameters:
input
- the input stream
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PositionFilter
public PositionFilter(TokenStream input, int positionIncrement)
Constructs a PositionFilter that assigns the given position increment to all but the first token from the given input stream.- Parameters:
input
- the input streampositionIncrement
- position increment to assign to all but the first token from the input stream
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Method Detail
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incrementToken
public final 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
Reset the filter as well as the input TokenStream.- Overrides:
reset
in classTokenFilter
- Throws:
IOException
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