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.AttributeFactory, AttributeSource.State
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Constructor Summary
Constructors Constructor Description HunspellStemFilter(TokenStream input, HunspellDictionary dictionary)
Create aHunspellStemFilter
which deduplicates stems and has a maximum recursion level of 2.HunspellStemFilter(TokenStream input, HunspellDictionary dictionary, boolean dedup)
Create aHunspellStemFilter
which has a maximum recursion level of 2.HunspellStemFilter(TokenStream input, HunspellDictionary dictionary, boolean dedup, int recursionCap)
Creates a new HunspellStemFilter that will stem tokens from the given TokenStream using affix rules in the provided HunspellDictionaryHunspellStemFilter(TokenStream input, HunspellDictionary dictionary, int recursionCap)
Creates a new HunspellStemFilter that will stem tokens from the given TokenStream using affix rules in the provided HunspellDictionary
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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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HunspellStemFilter
public HunspellStemFilter(TokenStream input, HunspellDictionary dictionary)
Create aHunspellStemFilter
which deduplicates stems and has a maximum recursion level of 2.
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HunspellStemFilter
public HunspellStemFilter(TokenStream input, HunspellDictionary dictionary, int recursionCap)
Creates a new HunspellStemFilter that will stem tokens from the given TokenStream using affix rules in the provided HunspellDictionary- Parameters:
input
- TokenStream whose tokens will be stemmeddictionary
- HunspellDictionary containing the affix rules and words that will be used to stem the tokensrecursionCap
- maximum level of recursion stemmer can go into, defaults to2
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HunspellStemFilter
public HunspellStemFilter(TokenStream input, HunspellDictionary dictionary, boolean dedup)
Create aHunspellStemFilter
which has a maximum recursion level of 2.
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HunspellStemFilter
public HunspellStemFilter(TokenStream input, HunspellDictionary dictionary, boolean dedup, int recursionCap)
Creates a new HunspellStemFilter that will stem tokens from the given TokenStream using affix rules in the provided HunspellDictionary- Parameters:
input
- TokenStream whose tokens will be stemmeddictionary
- HunspellDictionary containing the affix rules and words that will be used to stem the tokensdedup
- true if only unique terms should be output.recursionCap
- maximum level of recursion stemmer can go into, defaults to2
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Method Detail
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incrementToken
public boolean incrementToken() throws java.io.IOException
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
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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