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## org.apache.lucene.analysis.core
Class StopFilter

    java.lang.Object
      org.apache.lucene.util.AttributeSource
          org.apache.lucene.analysis.TokenStream
              org.apache.lucene.analysis.TokenFilter
                  org.apache.lucene.analysis.util.FilteringTokenFilter
                      org.apache.lucene.analysis.core.StopFilter

All Implemented Interfaces:
  Closeable

    public final class StopFilter

extends FilteringTokenFilter

Removes stop words from a token stream.

You must specify the required `Version` compatibility when creating StopFilter:

- As of 3.1, StopFilter correctly handles Unicode 4.0 supplementary characters in stopwords and position increments are preserved

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
`AttributeSource.AttributeFactory, AttributeSource.State`

Field Summary

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

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

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

Methods inherited from class org.apache.lucene.analysis.util.FilteringTokenFilter
`getEnablePositionIncrements, incrementToken, reset, setEnablePositionIncrements`

Methods inherited from class org.apache.lucene.analysis.TokenFilter
`close, end`

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`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### StopFilter

    public StopFilter(Version matchVersion,
                      TokenStream in,
                      CharArraySet stopWords)

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

  Parameters:
    `matchVersion` - Lucene version to enable correct Unicode 4.0 behavior in the stop set if Version > 3.0. See above for details.
    `in` - Input stream
    `stopWords` - A `CharArraySet` representing the stopwords.
  See Also:
    `makeStopSet(Version, java.lang.String...)`

Method Detail

### makeStopSet

    public static CharArraySet makeStopSet(Version matchVersion,
                                           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:
    `matchVersion` - Lucene version to enable correct Unicode 4.0 behavior in the returned set if Version > 3.0
    `stopWords` - An array of stopwords
  See Also:
    `passing false to ignoreCase`

### makeStopSet

    public static CharArraySet makeStopSet(Version matchVersion,
                                           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:
    `matchVersion` - Lucene version to enable correct Unicode 4.0 behavior in the returned set if Version > 3.0
    `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(Version matchVersion,
                                           String[] stopWords,
                                           boolean ignoreCase)

  Creates a stopword set from the given stopword array.

  Parameters:
    `matchVersion` - Lucene version to enable correct Unicode 4.0 behavior in the returned set if Version > 3.0
    `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(Version matchVersion,
                                           List<?> stopWords,
                                           boolean ignoreCase)

  Creates a stopword set from the given stopword list.

  Parameters:
    `matchVersion` - Lucene version to enable correct Unicode 4.0 behavior in the returned set if Version > 3.0
    `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`

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