org.apache.lucene.analysis.fa

Class PersianAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.util.StopwordAnalyzerBase

org.apache.lucene.analysis.fa.PersianAnalyzer

All Implemented Interfaces:

Closeable

public final class PersianAnalyzer
extends StopwordAnalyzerBase

Analyzer for Persian.

This Analyzer uses PersianCharFilter which implies tokenizing around zero-width non-joiner in addition to whitespace. Some persian-specific variant forms (such as farsi yeh and keheh) are standardized. "Stemming" is accomplished via stopwords.

Nested Class Summary

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

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

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_STOPWORD_FILE File containing default Persian stopwords.
static String	STOPWORDS_COMMENT The comment character in the stopwords file.

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

matchVersion, stopwords

Constructor Summary

Constructors

Constructor and Description
PersianAnalyzer(Version matchVersion) Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.
PersianAnalyzer(Version matchVersion, CharArraySet stopwords) Builds an analyzer with the given stop words

Method Summary

Methods

Modifier and Type	Method and Description
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.
protected Reader	initReader(String fieldName, Reader reader) Wraps the Reader with PersianCharFilter

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, 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 Persian 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

public static final String STOPWORDS_COMMENT

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

See Also:

Constant Field Values

Constructor Detail

PersianAnalyzer

public PersianAnalyzer(Version matchVersion)

Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.

PersianAnalyzer

public PersianAnalyzer(Version matchVersion,
               CharArraySet stopwords)

Builds an analyzer with the given stop words

Parameters:

matchVersion - lucene compatibility version

stopwords - a stopword set

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 a StandardTokenizer filtered with LowerCaseFilter, ArabicNormalizationFilter, PersianNormalizationFilter and Persian Stop words

initReader

protected Reader initReader(String fieldName,
                Reader reader)

Wraps the Reader with PersianCharFilter

Overrides:

initReader in class Analyzer