Class HunspellStemFilter
- 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.hunspell.HunspellStemFilter
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public final class HunspellStemFilter extends TokenFilter
TokenFilter that uses hunspell affix rules and words to stem tokens. Since hunspell supports a word having multiple stems, this filter can emit multiple tokens for each consumed tokenNote: This filter is aware of the
KeywordAttribute
. To prevent certain terms from being passed to the stemmerKeywordAttribute.isKeyword()
should be set totrue
in a previousTokenStream
. Note: For including the original term as well as the stemmed version, seeKeywordRepeatFilterFactory
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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 java.util.List<CharsRef>
buffer
private boolean
dedup
private KeywordAttribute
keywordAtt
(package private) static java.util.Comparator<CharsRef>
lengthComparator
private boolean
longestOnly
private PositionIncrementAttribute
posIncAtt
private AttributeSource.State
savedState
private Stemmer
stemmer
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 HunspellStemFilter(TokenStream input, Dictionary dictionary)
Create aHunspellStemFilter
outputting all possible stems.HunspellStemFilter(TokenStream input, Dictionary dictionary, boolean dedup)
Create aHunspellStemFilter
outputting all possible stems.HunspellStemFilter(TokenStream input, Dictionary dictionary, boolean dedup, boolean longestOnly)
Creates a new HunspellStemFilter that will stem tokens from the given TokenStream using affix rules in the provided Dictionary
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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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posIncAtt
private final PositionIncrementAttribute posIncAtt
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keywordAtt
private final KeywordAttribute keywordAtt
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stemmer
private final Stemmer stemmer
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buffer
private java.util.List<CharsRef> buffer
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savedState
private AttributeSource.State savedState
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dedup
private final boolean dedup
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longestOnly
private final boolean longestOnly
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lengthComparator
static final java.util.Comparator<CharsRef> lengthComparator
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Constructor Detail
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HunspellStemFilter
public HunspellStemFilter(TokenStream input, Dictionary dictionary)
Create aHunspellStemFilter
outputting all possible stems.
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HunspellStemFilter
public HunspellStemFilter(TokenStream input, Dictionary dictionary, boolean dedup)
Create aHunspellStemFilter
outputting all possible stems.
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HunspellStemFilter
public HunspellStemFilter(TokenStream input, Dictionary dictionary, boolean dedup, boolean longestOnly)
Creates a new HunspellStemFilter that will stem tokens from the given TokenStream using affix rules in the provided Dictionary- Parameters:
input
- TokenStream whose tokens will be stemmeddictionary
- HunspellDictionary containing the affix rules and words that will be used to stem the tokenslongestOnly
- true if only the longest term should be output.
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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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