org.apache.lucene.analysis.en

## Class KStemFilter

- java.lang.Object
- - org.apache.lucene.util.AttributeSource
  - - org.apache.lucene.analysis.TokenStream
    - - org.apache.lucene.analysis.TokenFilter
      - - org.apache.lucene.analysis.en.KStemFilter

- All Implemented Interfaces:
    Closeable, AutoCloseable

      public final class KStemFilter
      extends TokenFilter

  A high-performance kstem filter for english.

  See "Viewing Morphology as an Inference Process" (Krovetz, R., Proceedings of the Sixteenth Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, 191-203, 1993).

  All terms must already be lowercased for this filter to work correctly.

  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`

- - ### 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 and Description
    `KStemFilter(TokenStream in)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `incrementToken()` Returns the next, stemmed, input Token.

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

      `close, end, reset`

    - ### 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 Detail

    - #### KStemFilter

          public KStemFilter(TokenStream in)

  - ### Method Detail

    - #### incrementToken

          public boolean incrementToken()
                                 throws IOException

      Returns the next, stemmed, input Token.
      Specified by:
        `incrementToken` in class `TokenStream`
      Returns:
        The stemmed form of a token.
      Throws:
        `IOException` - If there is a low-level I/O error.

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