Package 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.GraphTokenFilter
org.apache.lucene.analysis.shingle.FixedShingleFilter

All Implemented Interfaces:
  `Closeable`, `AutoCloseable`, `Unwrappable<TokenStream>`

public final class FixedShingleFilter extends GraphTokenFilter
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.GraphTokenFilter

`MAX_GRAPH_STACK_SIZE, MAX_TOKEN_CACHE_SIZE`

### 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
`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

Modifier and Type
Method
Description
`boolean`
`incrementToken()`

### Methods inherited from class org.apache.lucene.analysis.GraphTokenFilter

`end, getTrailingPositions, incrementBaseToken, incrementGraph, incrementGraphToken, 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

### 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 Details

### incrementToken

public boolean incrementToken() throws IOException

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