Module org.apache.lucene.analysis.common

Package org.apache.lucene.analysis.fa

Class PersianAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.StopwordAnalyzerBase

org.apache.lucene.analysis.fa.PersianAnalyzer

All Implemented Interfaces:

Closeable, AutoCloseable

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.

Since:

3.1

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	PersianAnalyzer.DefaultSetHolder	Atomically loads the DEFAULT_STOP_SET in a lazy fashion once the outer class accesses the static final set the first time.;

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

Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents

Field Summary

Fields

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

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	Description
PersianAnalyzer()	Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.
PersianAnalyzer(CharArraySet stopwords)	Builds an analyzer with the given stop words

Method Summary

Modifier and Type	Method	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 Reader	initReader(String fieldName, Reader reader)	Wraps the Reader with PersianCharFilter
protected TokenStream	normalize(String fieldName, TokenStream in)	Wrap the given TokenStream in order to apply normalization filters.

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, initReaderForNormalization, normalize, tokenStream, tokenStream

Methods inherited from class java.lang.Object

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

Field Details

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 Details

PersianAnalyzer

public PersianAnalyzer()

Builds an analyzer with the default stop words: DEFAULT_STOPWORD_FILE.

PersianAnalyzer

public PersianAnalyzer(CharArraySet stopwords)

Builds an analyzer with the given stop words

Parameters:

stopwords - a stopword set

Method Details

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

Parameters:

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

Returns:

Analyzer.TokenStreamComponents built from a StandardTokenizer filtered with LowerCaseFilter, DecimalDigitFilter, ArabicNormalizationFilter, PersianNormalizationFilter and Persian Stop words

normalize

protected TokenStream normalize(String fieldName,
 TokenStream in)

Description copied from class: Analyzer

Wrap the given TokenStream in order to apply normalization filters. The default implementation returns the TokenStream as-is. This is used by Analyzer.normalize(String, String).

Overrides:

normalize in class Analyzer

initReader

protected Reader initReader(String fieldName,
 Reader reader)

Wraps the Reader with PersianCharFilter

Overrides:

initReader in class Analyzer

Parameters:

fieldName - IndexableField name being indexed

reader - original Reader

Returns:

reader, optionally decorated with CharFilter(s)