Package org.apache.lucene.analysis

Class StopFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.FilteringTokenFilter

org.apache.lucene.analysis.StopFilter

All Implemented Interfaces:

Closeable, AutoCloseable, Unwrappable<TokenStream>

public class StopFilter
extends FilteringTokenFilter

Removes stop words from a token stream.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.State

Field Summary

Fields inherited from class org.apache.lucene.analysis.TokenFilter

input

Fields inherited from class org.apache.lucene.analysis.TokenStream

DEFAULT_TOKEN_ATTRIBUTE_FACTORY

Constructor Summary

Constructors

Constructor	Description
StopFilter(TokenStream in, CharArraySet stopWords)	Constructs a filter which removes words from the input TokenStream that are named in the Set.

Method Summary

Modifier and Type	Method	Description
protected boolean	accept()	Returns the next input Token whose term() is not a stop word.
static CharArraySet	makeStopSet(String... stopWords)	Builds a Set from an array of stop words, appropriate for passing into the StopFilter constructor.
static CharArraySet	makeStopSet(String[] stopWords, boolean ignoreCase)	Creates a stopword set from the given stopword array.
static CharArraySet	makeStopSet(List<?> stopWords)	Builds a Set from an array of stop words, appropriate for passing into the StopFilter constructor.
static CharArraySet	makeStopSet(List<?> stopWords, boolean ignoreCase)	Creates a stopword set from the given stopword list.

Methods inherited from class org.apache.lucene.analysis.FilteringTokenFilter

end, incrementToken, reset

Methods inherited from class org.apache.lucene.analysis.TokenFilter

close, unwrap

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

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

StopFilter

public StopFilter(TokenStream in,
 CharArraySet stopWords)

Constructs a filter which removes words from the input TokenStream that are named in the Set.

Parameters:

in - Input stream

stopWords - A CharArraySet representing the stopwords.

See Also:

• makeStopSet(java.lang.String...)

Method Details

makeStopSet

public static CharArraySet makeStopSet(String... stopWords)

Builds a Set from an array of stop words, appropriate for passing into the StopFilter constructor. This permits this stopWords construction to be cached once when an Analyzer is constructed.

Parameters:

stopWords - An array of stopwords

See Also:

• passing false to ignoreCase

makeStopSet

public static CharArraySet makeStopSet(List<?> stopWords)

Builds a Set from an array of stop words, appropriate for passing into the StopFilter constructor. This permits this stopWords construction to be cached once when an Analyzer is constructed.

Parameters:

stopWords - A List of Strings or char[] or any other toString()-able list representing the stopwords

Returns:

A Set (CharArraySet) containing the words

See Also:

• passing false to ignoreCase

makeStopSet

public static CharArraySet makeStopSet(String[] stopWords,
 boolean ignoreCase)

Creates a stopword set from the given stopword array.

Parameters:

stopWords - An array of stopwords

ignoreCase - If true, all words are lower cased first.

Returns:

a Set containing the words

makeStopSet

public static CharArraySet makeStopSet(List<?> stopWords,
 boolean ignoreCase)

Creates a stopword set from the given stopword list.

Parameters:

stopWords - A List of Strings or char[] or any other toString()-able list representing the stopwords

ignoreCase - if true, all words are lower cased first

Returns:

A Set (CharArraySet) containing the words

accept

protected boolean accept()

Returns the next input Token whose term() is not a stop word.

Specified by:

accept in class FilteringTokenFilter