org.apache.lucene.analysis.en
Class PorterStemFilter
java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.en.PorterStemFilter
- All Implemented Interfaces:
- Closeable
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, Reader reader) {
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 stemmer
KeywordAttribute.isKeyword()
should be set to true
in a previous TokenStream
.
Note: For including the original term as well as the stemmed version, see
KeywordRepeatFilterFactory
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 |
PorterStemFilter
public PorterStemFilter(TokenStream in)
incrementToken
public final boolean incrementToken()
throws IOException
- Specified by:
incrementToken
in class TokenStream
- Throws:
IOException
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