Package org.apache.lucene.analysis.de
Class GermanAnalyzer
- java.lang.Object
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- org.apache.lucene.analysis.Analyzer
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- org.apache.lucene.analysis.StopwordAnalyzerBase
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- org.apache.lucene.analysis.de.GermanAnalyzer
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- All Implemented Interfaces:
Closeable,AutoCloseable
public final class GermanAnalyzer extends StopwordAnalyzerBase
Analyzerfor German language.Supports an external list of stopwords (words that will not be indexed at all) and an external list of exclusions (word that will not be stemmed, but indexed). A default set of stopwords is used unless an alternative list is specified, but the exclusion list is empty by default.
NOTE: This class uses the same
Versiondependent settings asStandardAnalyzer.NOTE: This class does not decompound nouns, additional data files are needed, incompatible with the Apache 2.0 License. You can find these data files and example code for decompounding here.
- Since:
- 3.1
- See Also:
- https://github.com/uschindler/german-decompounder
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.analysis.Analyzer
Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents
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Field Summary
Fields Modifier and Type Field Description static StringDEFAULT_STOPWORD_FILEFile containing default German stopwords.-
Fields inherited from class org.apache.lucene.analysis.StopwordAnalyzerBase
stopwords
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Fields inherited from class org.apache.lucene.analysis.Analyzer
GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY
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Constructor Summary
Constructors Constructor Description GermanAnalyzer()Builds an analyzer with the default stop words:getDefaultStopSet().GermanAnalyzer(CharArraySet stopwords)Builds an analyzer with the given stop wordsGermanAnalyzer(CharArraySet stopwords, CharArraySet stemExclusionSet)Builds an analyzer with the given stop words
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected Analyzer.TokenStreamComponentscreateComponents(String fieldName)CreatesAnalyzer.TokenStreamComponentsused to tokenize all the text in the providedReader.static CharArraySetgetDefaultStopSet()Returns a set of default German-stopwordsprotected TokenStreamnormalize(String fieldName, TokenStream in)-
Methods inherited from class org.apache.lucene.analysis.StopwordAnalyzerBase
getStopwordSet, loadStopwordSet, loadStopwordSet, loadStopwordSet
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Methods inherited from class org.apache.lucene.analysis.Analyzer
attributeFactory, close, getOffsetGap, getPositionIncrementGap, getReuseStrategy, initReader, initReaderForNormalization, normalize, tokenStream, tokenStream
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Field Detail
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DEFAULT_STOPWORD_FILE
public static final String DEFAULT_STOPWORD_FILE
File containing default German stopwords.- See Also:
- Constant Field Values
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Constructor Detail
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GermanAnalyzer
public GermanAnalyzer()
Builds an analyzer with the default stop words:getDefaultStopSet().
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GermanAnalyzer
public GermanAnalyzer(CharArraySet stopwords)
Builds an analyzer with the given stop words- Parameters:
stopwords- a stopword set
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GermanAnalyzer
public GermanAnalyzer(CharArraySet stopwords, CharArraySet stemExclusionSet)
Builds an analyzer with the given stop words- Parameters:
stopwords- a stopword setstemExclusionSet- a stemming exclusion set
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Method Detail
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getDefaultStopSet
public static final CharArraySet getDefaultStopSet()
Returns a set of default German-stopwords- Returns:
- a set of default German-stopwords
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createComponents
protected Analyzer.TokenStreamComponents createComponents(String fieldName)
CreatesAnalyzer.TokenStreamComponentsused to tokenize all the text in the providedReader.- Specified by:
createComponentsin classAnalyzer- Returns:
Analyzer.TokenStreamComponentsbuilt from aStandardTokenizerfiltered withLowerCaseFilter,StopFilter,SetKeywordMarkerFilterif a stem exclusion set is provided,GermanNormalizationFilterandGermanLightStemFilter
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normalize
protected TokenStream normalize(String fieldName, TokenStream in)
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