org.apache.lucene.analysis.ar

Class ArabicAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.ReusableAnalyzerBase

org.apache.lucene.analysis.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.ReusableAnalyzerBase

ReusableAnalyzerBase.TokenStreamComponents

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_STOPWORD_FILE File containing default Arabic stopwords.
static String	STOPWORDS_COMMENT Deprecated. use WordlistLoader.getWordSet(Reader, String, Version) directly

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

matchVersion, stopwords

Constructor Summary

Constructors

Constructor and Description
ArabicAnalyzer(Version matchVersion) Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.
ArabicAnalyzer(Version matchVersion, File stopwords) Deprecated. use ArabicAnalyzer(Version, Set) instead
ArabicAnalyzer(Version matchVersion, Hashtable<?,?> stopwords) Deprecated. use ArabicAnalyzer(Version, Set) instead
ArabicAnalyzer(Version matchVersion, Set<?> stopwords) Builds an analyzer with the given stop words
ArabicAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionSet) Builds an analyzer with the given stop word.
ArabicAnalyzer(Version matchVersion, String... stopwords) Deprecated. use ArabicAnalyzer(Version, Set) instead

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 an unmodifiable instance of the default stop-words set.

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

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

STOPWORDS_COMMENT

@Deprecated
public static final String STOPWORDS_COMMENT

Deprecated. use WordlistLoader.getWordSet(Reader, String, Version) directly

The comment character in the stopwords file. All lines prefixed with this will be ignored

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,
              Set<?> stopwords)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

ArabicAnalyzer

public ArabicAnalyzer(Version matchVersion,
              Set<?> stopwords,
              Set<?> 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

ArabicAnalyzer

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

Deprecated. use ArabicAnalyzer(Version, Set) instead

Builds an analyzer with the given stop words.

ArabicAnalyzer

@Deprecated
public ArabicAnalyzer(Version matchVersion,
                         Hashtable<?,?> stopwords)

Deprecated. use ArabicAnalyzer(Version, Set) instead

Builds an analyzer with the given stop words.

ArabicAnalyzer

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

Deprecated. use ArabicAnalyzer(Version, Set) instead

Builds an analyzer with the given stop words. Lines can be commented out using STOPWORDS_COMMENT

Throws:

IOException

Method Detail

getDefaultStopSet

public static Set<?> getDefaultStopSet()

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

Returns:

an unmodifiable instance of the default stop-words set.

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