org.apache.lucene.analysis.de
Class GermanAnalyzer

java.lang.Object
  org.apache.lucene.analysis.Analyzer
      org.apache.lucene.analysis.util.StopwordAnalyzerBase
          org.apache.lucene.analysis.de.GermanAnalyzer

All Implemented Interfaces:

Closeable

public final class GermanAnalyzer
extends StopwordAnalyzerBase

Analyzer for 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.

You must specify the required Version compatibility when creating GermanAnalyzer:

• As of 3.6, GermanLightStemFilter is used for less aggressive stemming.
• As of 3.1, Snowball stemming is done with SnowballFilter, and Snowball stopwords are used by default.
• As of 2.9, StopFilter preserves position increments

NOTE: This class uses the same Version dependent settings as StandardAnalyzer.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.analysis.Analyzer

Analyzer.GlobalReuseStrategy, Analyzer.PerFieldReuseStrategy, Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents

Field Summary

static String

DEFAULT_STOPWORD_FILE File containing default German stopwords.

Fields inherited from class org.apache.lucene.analysis.util.StopwordAnalyzerBase

matchVersion, stopwords

Constructor Summary

GermanAnalyzer(Version matchVersion)
Builds an analyzer with the default stop words: getDefaultStopSet().

GermanAnalyzer(Version matchVersion, CharArraySet stopwords)
Builds an analyzer with the given stop words

GermanAnalyzer(Version matchVersion, CharArraySet stopwords, CharArraySet stemExclusionSet)
Builds an analyzer with the given stop words

Method Summary

protected Analyzer.TokenStreamComponents	createComponents(String fieldName, Reader reader) Creates Analyzer.TokenStreamComponents used to tokenize all the text in the provided Reader.
static CharArraySet	getDefaultStopSet() Returns a set of default German-stopwords

Methods inherited from class org.apache.lucene.analysis.util.StopwordAnalyzerBase

getStopwordSet, loadStopwordSet, loadStopwordSet, loadStopwordSet

Methods inherited from class org.apache.lucene.analysis.Analyzer

close, getOffsetGap, getPositionIncrementGap, initReader, tokenStream

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_STOPWORD_FILE

public static final String DEFAULT_STOPWORD_FILE

File containing default German stopwords.

See Also:

Constant Field Values

Constructor Detail

GermanAnalyzer

public GermanAnalyzer(Version matchVersion)

Builds an analyzer with the default stop words: getDefaultStopSet().

GermanAnalyzer

public GermanAnalyzer(Version matchVersion,
                      CharArraySet stopwords)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

GermanAnalyzer

public GermanAnalyzer(Version matchVersion,
                      CharArraySet stopwords,
                      CharArraySet stemExclusionSet)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

stemExclusionSet - a stemming exclusion set

Method Detail

getDefaultStopSet

public static final CharArraySet getDefaultStopSet()

Returns a set of default German-stopwords

Returns:

a set of default German-stopwords

createComponents

protected Analyzer.TokenStreamComponents createComponents(String fieldName,
                                                          Reader reader)

Creates Analyzer.TokenStreamComponents used to tokenize all the text in the provided Reader.

Specified by:

createComponents in class Analyzer

Returns:

Analyzer.TokenStreamComponents built from a StandardTokenizer filtered with StandardFilter, LowerCaseFilter, StopFilter , KeywordMarkerFilter if a stem exclusion set is provided, GermanNormalizationFilter and GermanLightStemFilter