Package org.apache.lucene.analysis.ja

# Class JapaneseKatakanaStemFilter

java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.ja.JapaneseKatakanaStemFilter

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

public final class JapaneseKatakanaStemFilter extends TokenFilter
A `TokenFilter` that normalizes common katakana spelling variations ending in a long sound character by removing this character (U+30FC). Only katakana words longer than a minimum length are stemmed (default is four).

Note that only full-width katakana characters are supported. Please use a `CJKWidthFilter` to convert half-width katakana to full-width before using this filter.

In order to prevent terms from being stemmed, use an instance of `SetKeywordMarkerFilter` or a custom `TokenFilter` that sets the `KeywordAttribute` before this `TokenStream`.

## Nested Class Summary

## Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

`AttributeSource.State`

## Field Summary

Fields
Modifier and Type
Field
Description
`static final int`
`DEFAULT_MINIMUM_LENGTH`

### 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
`JapaneseKatakanaStemFilter(TokenStream input)`
`JapaneseKatakanaStemFilter(TokenStream input, int minimumLength)`

## Method Summary

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

### 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`

## Field Details

### DEFAULT_MINIMUM_LENGTH

public static final int DEFAULT_MINIMUM_LENGTH

See Also:
  - Constant Field Values

## Constructor Details

### JapaneseKatakanaStemFilter

public JapaneseKatakanaStemFilter(TokenStream input, int minimumLength)

### JapaneseKatakanaStemFilter

public JapaneseKatakanaStemFilter(TokenStream input)

## Method Details

### incrementToken

public boolean incrementToken() throws IOException

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