Package org.apache.lucene.analysis.snowball

# Class SnowballFilter

java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.snowball.SnowballFilter

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

public final class SnowballFilter extends TokenFilter
A filter that stems words using a Snowball-generated stemmer.

Available stemmers are listed in `org.tartarus.snowball.ext`.

NOTE: SnowballFilter expects lowercased text.

- For the Turkish language, see `TurkishLowerCaseFilter`.
- For other languages, see `LowerCaseFilter`.

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
Description
`SnowballFilter(TokenStream in, String name)`
Construct the named stemming filter.
`SnowballFilter(TokenStream input, SnowballStemmer stemmer)`

## Method Summary

Modifier and Type
Method
Description
`final boolean`
`incrementToken()`
Returns the next input Token, after being stemmed

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

`close, end, reset, 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

### SnowballFilter

public SnowballFilter(TokenStream input, SnowballStemmer stemmer)

### SnowballFilter

public SnowballFilter(TokenStream in, String name)
Construct the named stemming filter.

Available stemmers are listed in `org.tartarus.snowball.ext`. The name of a stemmer is the part of the class name before "Stemmer", e.g., the stemmer in `EnglishStemmer` is named "English".

Parameters:
  `in` - the input tokens to stem
  `name` - the name of a stemmer

## Method Details

### incrementToken

public final boolean incrementToken() throws IOException
Returns the next input Token, after being stemmed

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