edu.northwestern.at.utils.corpuslinguistics.stemmer
Class PorterStemmer

java.lang.Object
  edu.northwestern.at.utils.corpuslinguistics.stemmer.PorterStemmer

All Implemented Interfaces:

Stemmer

public class PorterStemmer
extends java.lang.Object
implements Stemmer

Stemmer, implementing the Porter Stemming Algorithm The Stemmer class transforms a word into its root form. The input word can be provided a character at time (by calling add()), or at once by calling one of the various stem(something) methods.

Field Summary

protected char[]	b
protected int	i
protected int	i_end
protected static int	INC
protected int	j
protected int	k

Constructor Summary

PorterStemmer()

Method Summary

void	add(char ch) Add a character to the word being stemmed.
void	add(char[] w, int wLen) Adds wLen characters to the word being stemmed contained in a portion of a char[] array.
protected boolean	cons(int i)
protected boolean	cvc(int i)
protected boolean	doublec(int j)
protected boolean	ends(java.lang.String s)
char[]	getResultBuffer() Returns a reference to a character buffer containing the results of the stemming process.
int	getResultLength() Returns the length of the word resulting from the stemming process.
protected int	m()
protected void	r(java.lang.String s)
protected void	setto(java.lang.String s)
void	stem() Stem the word placed into the Stemmer buffer through calls to add().
java.lang.String	stem(java.lang.String word) Find stem of a single word.
protected void	step1()
protected void	step2()
protected void	step3()
protected void	step4()
protected void	step5()
protected void	step6()
java.lang.String	toString() After a word has been stemmed, it can be retrieved by toString(), or a reference to the internal buffer can be retrieved by getResultBuffer and getResultLength (which is generally more efficient.)
protected boolean	vowelinstem()

Methods inherited from class java.lang.Object

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

Field Detail

b

protected char[] b

i

protected int i

i_end

protected int i_end

j

protected int j

k

protected int k

INC

protected static final int INC

See Also:

Constant Field Values

Constructor Detail

PorterStemmer

public PorterStemmer()

Method Detail

add

public void add(char ch)

Add a character to the word being stemmed. When you are finished adding characters, you can call stem(void) to stem the word.

add

public void add(char[] w,
                int wLen)

Adds wLen characters to the word being stemmed contained in a portion of a char[] array. This is like repeated calls of add(char ch), but faster.

toString

public java.lang.String toString()

After a word has been stemmed, it can be retrieved by toString(), or a reference to the internal buffer can be retrieved by getResultBuffer and getResultLength (which is generally more efficient.)

Overrides:

toString in class java.lang.Object

getResultLength

public int getResultLength()

Returns the length of the word resulting from the stemming process.

getResultBuffer

public char[] getResultBuffer()

Returns a reference to a character buffer containing the results of the stemming process. You also need to consult getResultLength() to determine the length of the result.

cons

protected final boolean cons(int i)

m

protected final int m()

vowelinstem

protected final boolean vowelinstem()

doublec

protected final boolean doublec(int j)

cvc

protected final boolean cvc(int i)

ends

protected final boolean ends(java.lang.String s)

setto

protected final void setto(java.lang.String s)

r

protected final void r(java.lang.String s)

step1

protected final void step1()

step2

protected final void step2()

step3

protected final void step3()

step4

protected final void step4()

step5

protected final void step5()

step6

protected final void step6()

stem

public void stem()

Stem the word placed into the Stemmer buffer through calls to add(). Returns true if the stemming process resulted in a word different from the input. You can retrieve the result with getResultLength()/getResultBuffer() or toString().

stem

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

Description copied from interface: Stemmer

Find stem of a single word.

Specified by:

stem in interface Stemmer

Parameters:

word - The word whose stem is desired.

Returns:

The word stem.