uk.ac.gla.terrier.terms
Class PorterStemmer

java.lang.Object
  uk.ac.gla.terrier.terms.PorterStemmer

All Implemented Interfaces:

TermPipeline

Direct Known Subclasses:

WeakPorterStemmer

public class PorterStemmer
extends java.lang.Object
implements TermPipeline

This is the Porter stemming algorithm, coded up in JAVA by Gianni Amati. All comments were made by Porter, but few ones due to some implementation choices.
Porter says "It may be be regarded as cononical, in that it follows the algorithm presented in Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14, no. 3, pp 130-137, only differing from it at the points marked --DEPARTURE-- below. The algorithm as described in the paper could be exactly replicated by adjusting the points of DEPARTURE, but this is barely necessary, because (a) the points of DEPARTURE are definitely improvements, and (b) no encoding of the Porter stemmer I have seen is anything like as exact as this version, even with the points of DEPARTURE!".
This class is not thread safe.

Version:

$Revision: 1.10 $

Author:

Gianni Amati, modified into a TermPipeline and (Java) optimised by Craig Macdonald

Field Summary

static char[]

b A buffer for word to be stemmed.

Constructor Summary

PorterStemmer(TermPipeline next)
Constructs an instance of the class, given the next component in the pipeline.

Method Summary

void	processTerm(java.lang.String t) Stems the given term.
java.lang.String	stem(java.lang.String s) Returns the stem of a given term

Methods inherited from class java.lang.Object

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

Field Detail

b

public static char[] b

A buffer for word to be stemmed.

Constructor Detail

PorterStemmer

public PorterStemmer(TermPipeline next)

Constructs an instance of the class, given the next component in the pipeline.

Parameters:

next - TermPipeline the next component in the term pipeline.

Method Detail

processTerm

public void processTerm(java.lang.String t)

Stems the given term.

Specified by:

processTerm in interface TermPipeline

Parameters:

t - String the term to stem.

stem

public java.lang.String stem(java.lang.String s)

Returns the stem of a given term

Parameters:

s - String the term to be stemmed.

Returns:

String the stem of a given term.