Package org.apache.lucene.analysis.br

Class BrazilianStemmer

java.lang.Object

org.apache.lucene.analysis.br.BrazilianStemmer

public class BrazilianStemmer
extends Object

A stemmer for Brazilian Portuguese words.

Field Summary

Fields

Modifier and Type	Field	Description
private String	CT
private static final Locale	locale
private String	R1
private String	R2
private String	RV
private String	TERM	Changed term

Constructor Summary

Constructors

Constructor	Description
BrazilianStemmer()

Method Summary

Modifier and Type	Method	Description
private String	changeTerm(String value)	1) Turn to lowercase 2) Remove accents 3) ã -> a ; õ -> o 4) ç -> c
private void	createCT(String term)	Creates CT (changed term) , substituting * 'ã' and 'õ' for 'a~' and 'o~'.
private String	getR1(String value)	Gets R1 R1 - is the region after the first non-vowel following a vowel, or is the null region at the end of the word if there is no such non-vowel.
private String	getRV(String value)	Gets RV RV - IF the second letter is a consonant, RV is the region after the next following vowel, OR if the first two letters are vowels, RV is the region after the next consonant, AND otherwise (consonant-vowel case) RV is the region after the third letter.
private boolean	isIndexable(String term)	Checks a term if it can be processed indexed.
private boolean	isStemmable(String term)	Checks a term if it can be processed correctly.
private boolean	isVowel(char value)	See if string is 'a','e','i','o','u'
String	log()	For log and debug purpose
private String	removeSuffix(String value, String toRemove)	Remove a string suffix
private String	replaceSuffix(String value, String toReplace, String changeTo)	Replace a string suffix by another
protected String	stem(String term)	Stems the given term to an unique discriminator.
private boolean	step1()	Standard suffix removal.
private boolean	step2()	Verb suffixes.
private void	step3()	Delete suffix 'i' if in RV and preceded by 'c'
private void	step4()	Residual suffix If the word ends with one of the suffixes (os a i o á í ó) in RV, delete it
private void	step5()	If the word ends with one of ( e é ê) in RV,delete it, and if preceded by 'gu' (or 'ci') with the 'u' (or 'i') in RV, delete the 'u' (or 'i') Or if the word ends ç remove the cedilha
private boolean	suffix(String value, String suffix)	Check if a string ends with a suffix
private boolean	suffixPreceded(String value, String suffix, String preceded)	See if a suffix is preceded by a String

Methods inherited from class java.lang.Object

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

Field Details

locale

private static final Locale locale

TERM

private String TERM

Changed term

CT

private String CT

R1

private String R1

R2

private String R2

RV

private String RV

Constructor Details

BrazilianStemmer

public BrazilianStemmer()

Method Details

stem

protected String stem(String term)

Stems the given term to an unique discriminator.

Parameters:

term - The term that should be stemmed.

Returns:

Discriminator for term

isStemmable

private boolean isStemmable(String term)

Checks a term if it can be processed correctly.

Returns:

true if, and only if, the given term consists in letters.

isIndexable

private boolean isIndexable(String term)

Checks a term if it can be processed indexed.

Returns:

true if it can be indexed

isVowel

private boolean isVowel(char value)

See if string is 'a','e','i','o','u'

Returns:

true if is vowel

getR1

private String getR1(String value)

Gets R1 R1 - is the region after the first non-vowel following a vowel, or is the null region at the end of the word if there is no such non-vowel.

Returns:

null or a string representing R1

getRV

private String getRV(String value)

Gets RV RV - IF the second letter is a consonant, RV is the region after the next following vowel, OR if the first two letters are vowels, RV is the region after the next consonant, AND otherwise (consonant-vowel case) RV is the region after the third letter. BUT RV is the end of the word if this positions cannot be found.

Returns:

null or a string representing RV

changeTerm

private String changeTerm(String value)

1) Turn to lowercase 2) Remove accents 3) ã -> a ; õ -> o 4) ç -> c

Returns:

null or a string transformed

suffix

private boolean suffix(String value,
 String suffix)

Check if a string ends with a suffix

Returns:

true if the string ends with the specified suffix

replaceSuffix

private String replaceSuffix(String value,
 String toReplace,
 String changeTo)

Replace a string suffix by another

Returns:

the replaced String

removeSuffix

private String removeSuffix(String value,
 String toRemove)

Remove a string suffix

Returns:

the String without the suffix

suffixPreceded

private boolean suffixPreceded(String value,
 String suffix,
 String preceded)

See if a suffix is preceded by a String

Returns:

true if the suffix is preceded

createCT

private void createCT(String term)

Creates CT (changed term) , substituting * 'ã' and 'õ' for 'a~' and 'o~'.

step1

private boolean step1()

Standard suffix removal. Search for the longest among the following suffixes, and perform the following actions:

Returns:

false if no ending was removed

step2

private boolean step2()

Verb suffixes. Search for the longest among the following suffixes in RV, and if found, delete.

Returns:

false if no ending was removed

step3

private void step3()

Delete suffix 'i' if in RV and preceded by 'c'

step4

private void step4()

Residual suffix If the word ends with one of the suffixes (os a i o á í ó) in RV, delete it

step5

private void step5()

If the word ends with one of ( e é ê) in RV,delete it, and if preceded by 'gu' (or 'ci') with the 'u' (or 'i') in RV, delete the 'u' (or 'i') Or if the word ends ç remove the cedilha

log

public String log()

For log and debug purpose

Returns:

TERM, CT, RV, R1 and R2