GermanNormalizationFilter (Lucene 9.0.0 common API)

java.lang.Object
- org.apache.lucene.util.AttributeSource
- - org.apache.lucene.analysis.TokenStream
  - - org.apache.lucene.analysis.TokenFilter
    - - org.apache.lucene.analysis.de.GermanNormalizationFilter

All Implemented Interfaces:

Closeable, AutoCloseable
```
public final class GermanNormalizationFilter
extends TokenFilter
```
Normalizes German characters according to the heuristics of the German2 snowball algorithm. It allows for the fact that ä, ö and ü are sometimes written as ae, oe and ue.
- 'ß' is replaced by 'ss'
- 'ä', 'ö', 'ü' are replaced by 'a', 'o', 'u', respectively.
- 'ae' and 'oe' are replaced by 'a', and 'o', respectively.
- 'ue' is replaced by 'u', when not following a vowel or q.
This is useful if you want this normalization without using the German2 stemmer, or perhaps no stemming at all.

- 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
  
  GermanNormalizationFilter(TokenStream input)
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  boolean incrementToken()
  - 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

GermanNormalizationFilter

public GermanNormalizationFilter(TokenStream input)

Method Detail
- incrementToken
```
public boolean incrementToken()
                       throws IOException
```
  Specified by:
  
  incrementToken in class TokenStream
  
  Throws:
  
  IOException