Class DelimitedBoostTokenFilter
- 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.boost.DelimitedBoostTokenFilter
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
,Unwrappable<TokenStream>
public final class DelimitedBoostTokenFilter extends TokenFilter
Characters before the delimiter are the "token", those after are the boost.For example, if the delimiter is '|', then for the string "foo|0.7", foo is the token and 0.7 is the boost.
Note make sure your Tokenizer doesn't split on the delimiter, or this won't work
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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 BoostAttribute
boostAtt
private char
delimiter
private CharTermAttribute
termAtt
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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 DelimitedBoostTokenFilter(TokenStream input, char delimiter)
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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.-
Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end, reset, unwrap
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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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delimiter
private final char delimiter
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termAtt
private final CharTermAttribute termAtt
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boostAtt
private final BoostAttribute boostAtt
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Constructor Detail
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DelimitedBoostTokenFilter
public DelimitedBoostTokenFilter(TokenStream input, char delimiter)
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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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