org.apache.lucene.analysis.de

Class GermanAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.ReusableAnalyzerBase

org.apache.lucene.analysis.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.ReusableAnalyzerBase

ReusableAnalyzerBase.TokenStreamComponents

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_STOPWORD_FILE File containing default German stopwords.
static String[]	GERMAN_STOP_WORDS Deprecated. use getDefaultStopSet() instead

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

matchVersion, stopwords

Constructor Summary

Constructors

Constructor and Description
GermanAnalyzer(Version matchVersion) Builds an analyzer with the default stop words: getDefaultStopSet().
GermanAnalyzer(Version matchVersion, File stopwords) Deprecated. use GermanAnalyzer(Version, Set)
GermanAnalyzer(Version matchVersion, Map<?,?> stopwords) Deprecated. use GermanAnalyzer(Version, Set)
GermanAnalyzer(Version matchVersion, Set<?> stopwords) Builds an analyzer with the given stop words
GermanAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionSet) Builds an analyzer with the given stop words
GermanAnalyzer(Version matchVersion, String... stopwords) Deprecated. use GermanAnalyzer(Version, Set)

Method Summary

Methods

Modifier and Type	Method and Description
protected ReusableAnalyzerBase.TokenStreamComponents	createComponents(String fieldName, Reader reader) Creates ReusableAnalyzerBase.TokenStreamComponents used to tokenize all the text in the provided Reader.
static Set<?>	getDefaultStopSet() Returns a set of default German-stopwords
void	setStemExclusionTable(File exclusionlist) Deprecated. use GermanAnalyzer(Version, Set, Set) instead
void	setStemExclusionTable(Map<?,?> exclusionlist) Deprecated. use GermanAnalyzer(Version, Set, Set) instead
void	setStemExclusionTable(String[] exclusionlist) Deprecated. use GermanAnalyzer(Version, Set, Set) instead

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

getStopwordSet, loadStopwordSet, loadStopwordSet, loadStopwordSet

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

initReader, reusableTokenStream, tokenStream

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

close, getOffsetGap, getPositionIncrementGap, getPreviousTokenStream, setPreviousTokenStream

Methods inherited from class java.lang.Object

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

Field Detail

GERMAN_STOP_WORDS

@Deprecated
public static final String[] GERMAN_STOP_WORDS

Deprecated. use getDefaultStopSet() instead

List of typical german stopwords.

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,
              Set<?> stopwords)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

GermanAnalyzer

public GermanAnalyzer(Version matchVersion,
              Set<?> stopwords,
              Set<?> stemExclusionSet)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

stemExclusionSet - a stemming exclusion set

GermanAnalyzer

@Deprecated
public GermanAnalyzer(Version matchVersion,
                         String... stopwords)

Deprecated. use GermanAnalyzer(Version, Set)

Builds an analyzer with the given stop words.

GermanAnalyzer

@Deprecated
public GermanAnalyzer(Version matchVersion,
                         Map<?,?> stopwords)

Deprecated. use GermanAnalyzer(Version, Set)

Builds an analyzer with the given stop words.

GermanAnalyzer

@Deprecated
public GermanAnalyzer(Version matchVersion,
                         File stopwords)
               throws IOException

Deprecated. use GermanAnalyzer(Version, Set)

Builds an analyzer with the given stop words.

Throws:

IOException

Method Detail

getDefaultStopSet

public static final Set<?> getDefaultStopSet()

Returns a set of default German-stopwords

Returns:

a set of default German-stopwords

setStemExclusionTable

@Deprecated
public void setStemExclusionTable(String[] exclusionlist)

Deprecated. use GermanAnalyzer(Version, Set, Set) instead

Builds an exclusionlist from an array of Strings.

setStemExclusionTable

@Deprecated
public void setStemExclusionTable(Map<?,?> exclusionlist)

Deprecated. use GermanAnalyzer(Version, Set, Set) instead

Builds an exclusionlist from a Map

setStemExclusionTable

@Deprecated
public void setStemExclusionTable(File exclusionlist)
                           throws IOException

Deprecated. use GermanAnalyzer(Version, Set, Set) instead

Builds an exclusionlist from the words contained in the given file.

Throws:

IOException

createComponents

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

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

Specified by:

createComponents in class ReusableAnalyzerBase

Parameters:

fieldName - the name of the fields content passed to the ReusableAnalyzerBase.TokenStreamComponents sink as a reader

reader - the reader passed to the Tokenizer constructor

Returns:

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