org.apache.lucene.analysis.ar

Class ArabicAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.StopwordAnalyzerBase

org.apache.lucene.analysis.ar.ArabicAnalyzer

All Implemented Interfaces:

Closeable, AutoCloseable

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.

Since:

3.1

Nested Class Summary

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

Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_STOPWORD_FILE File containing default Arabic stopwords.

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

stopwords

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

GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY

Constructor Summary

Constructors

Constructor and Description
ArabicAnalyzer() Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.
ArabicAnalyzer(CharArraySet stopwords) Builds an analyzer with the given stop words
ArabicAnalyzer(CharArraySet stopwords, CharArraySet stemExclusionSet) Builds an analyzer with the given stop word.

Method Summary

Modifier and Type	Method and Description
protected Analyzer.TokenStreamComponents	createComponents(String fieldName) 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.
protected TokenStream	normalize(String fieldName, TokenStream in)

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

getStopwordSet, loadStopwordSet, loadStopwordSet, loadStopwordSet

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

attributeFactory, close, getOffsetGap, getPositionIncrementGap, getReuseStrategy, getVersion, initReader, initReaderForNormalization, normalize, setVersion, tokenStream, 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()

Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.

ArabicAnalyzer

public ArabicAnalyzer(CharArraySet stopwords)

Builds an analyzer with the given stop words

Parameters:

stopwords - a stopword set

ArabicAnalyzer

public ArabicAnalyzer(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 SetKeywordMarkerFilter before ArabicStemFilter.

Parameters:

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)

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, DecimalDigitFilter, StopFilter, ArabicNormalizationFilter, SetKeywordMarkerFilter if a stem exclusion set is provided and ArabicStemFilter.

normalize

protected TokenStream normalize(String fieldName,
                                TokenStream in)

Overrides:

normalize in class Analyzer