Package org.apache.lucene.analysis.en
Class PorterStemFilter
- 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.en.PorterStemFilter
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- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
public final class PorterStemFilter extends TokenFilter
Transforms the token stream as per the Porter stemming algorithm. Note: the input to the stemming filter must already be in lower case, so you will need to use LowerCaseFilter or LowerCaseTokenizer farther down the Tokenizer chain in order for this to work properly!To use this filter with other analyzers, you'll want to write an Analyzer class that sets up the TokenStream chain as you want it. To use this with LowerCaseTokenizer, for example, you'd write an analyzer like this:
class MyAnalyzer extends Analyzer { @Override protected TokenStreamComponents createComponents(String fieldName) { Tokenizer source = new LowerCaseTokenizer(version, reader); return new TokenStreamComponents(source, new PorterStemFilter(source)); } }
Note: 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, see
KeywordRepeatFilterFactory
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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
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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 PorterStemFilter(TokenStream in)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
incrementToken()
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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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Constructor Detail
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PorterStemFilter
public PorterStemFilter(TokenStream in)
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Method Detail
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incrementToken
public final boolean incrementToken() throws IOException
- Specified by:
incrementToken
in classTokenStream
- Throws:
IOException
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