org.apache.lucene.analysis.shingle

## Class FixedShingleFilter

- java.lang.Object
- - org.apache.lucene.util.AttributeSource
  - - org.apache.lucene.analysis.TokenStream
    - - org.apache.lucene.analysis.TokenFilter
      - - org.apache.lucene.analysis.shingle.FixedShingleFilter

- All Implemented Interfaces:
    Closeable, AutoCloseable

      public final class FixedShingleFilter
      extends TokenFilter

  A FixedShingleFilter constructs shingles (token n-grams) from a token stream. In other words, it creates combinations of tokens as a single token.

  Unlike the `ShingleFilter`, FixedShingleFilter only emits shingles of a fixed size, and never emits unigrams, even at the end of a TokenStream. In addition, if the filter encounters stacked tokens (eg synonyms), then it will output stacked shingles

  For example, the sentence "please divide this sentence into shingles" might be tokenized into shingles "please divide", "divide this", "this sentence", "sentence into", and "into shingles".

  This filter handles position increments > 1 by inserting filler tokens (tokens with termtext "_").

  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### 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
    `FixedShingleFilter(TokenStream input, int shingleSize)` Creates a FixedShingleFilter over an input token stream
    `FixedShingleFilter(TokenStream input, int shingleSize, String tokenSeparator, String fillerToken)` Creates a FixedShingleFilter over an input token stream

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `end()`
    `boolean` | `incrementToken()`
    `void` | `reset()`

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

      `close`

    - ### 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

    - #### FixedShingleFilter

          public FixedShingleFilter(TokenStream input,
                                    int shingleSize)

      Creates a FixedShingleFilter over an input token stream
      Parameters:
        `input` - the input stream
        `shingleSize` - the shingle size

    - #### FixedShingleFilter

          public FixedShingleFilter(TokenStream input,
                                    int shingleSize,
                                    String tokenSeparator,
                                    String fillerToken)

      Creates a FixedShingleFilter over an input token stream
      Parameters:
        `input` - the input tokenstream
        `shingleSize` - the shingle size
        `tokenSeparator` - a String to use as a token separator
        `fillerToken` - a String to use to represent gaps in the input stream (due to eg stopwords)

  - ### Method Detail

    - #### incrementToken

          public boolean incrementToken()
                                 throws IOException

      Specified by:
        `incrementToken` in class `TokenStream`
      Throws:
        `IOException`

    - #### reset

          public void reset()
                     throws IOException

      Overrides:
        `reset` in class `TokenFilter`
      Throws:
        `IOException`

    - #### end

          public void end()
                   throws IOException

      Overrides:
        `end` in class `TokenFilter`
      Throws:
        `IOException`

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