org.apache.lucene.analysis.ar
Class ArabicAnalyzer

java.lang.Object
  org.apache.lucene.analysis.Analyzer
      org.apache.lucene.analysis.util.StopwordAnalyzerBase
          org.apache.lucene.analysis.ar.ArabicAnalyzer

All Implemented Interfaces:

Closeable

public final class ArabicAnalyzer
extends StopwordAnalyzerBase

Analyzer for Arabic.

This analyzer implements light-stemming as specified by: Light Stemming for Arabic Information Retrieval http://www.mtholyoke.edu/~lballest/Pubs/arab_stem05.pdf

The analysis package contains three primary components:

• ArabicNormalizationFilter: Arabic orthographic normalization.
• ArabicStemFilter: Arabic light stemming
• Arabic stop words file: a set of default Arabic stop words.

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 Arabic stopwords.

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

matchVersion, stopwords

Constructor Summary

ArabicAnalyzer(Version matchVersion)
Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.

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

ArabicAnalyzer(Version matchVersion, CharArraySet stopwords, CharArraySet stemExclusionSet)
Builds an analyzer with the given stop word.

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 an unmodifiable instance of the default stop-words set.

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 Arabic stopwords. Default stopword list is from http://members.unine.ch/jacques.savoy/clef/index.html The stopword list is BSD-Licensed.

See Also:

Constant Field Values

Constructor Detail

ArabicAnalyzer

public ArabicAnalyzer(Version matchVersion)

Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.

ArabicAnalyzer

public ArabicAnalyzer(Version matchVersion,
                      CharArraySet stopwords)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

ArabicAnalyzer

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

Builds an analyzer with the given stop word. If a none-empty stem exclusion set is provided this analyzer will add a KeywordMarkerFilter before ArabicStemFilter.

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

stemExclusionSet - a set of terms not to be stemmed

Method Detail

getDefaultStopSet

public static CharArraySet getDefaultStopSet()

Returns an unmodifiable instance of the default stop-words set.

Returns:

an unmodifiable instance of the default stop-words set.

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 an StandardTokenizer filtered with LowerCaseFilter, StopFilter, ArabicNormalizationFilter, KeywordMarkerFilter if a stem exclusion set is provided and ArabicStemFilter.