Package org.apache.lucene.analysis.de
Class GermanNormalizationFilter
- java.lang.Object
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- org.apache.lucene.util.AttributeSource
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- org.apache.lucene.analysis.TokenStream
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- org.apache.lucene.analysis.TokenFilter
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- org.apache.lucene.analysis.de.GermanNormalizationFilter
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class GermanNormalizationFilter extends org.apache.lucene.analysis.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.
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Constructor Summary
Constructors Constructor Description GermanNormalizationFilter(org.apache.lucene.analysis.TokenStream input)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
incrementToken()
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Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
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Method Detail
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incrementToken
public boolean incrementToken() throws IOException
- Specified by:
incrementToken
in classorg.apache.lucene.analysis.TokenStream
- Throws:
IOException
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