SimpleStemmer (JWI 2.4.0 API)

java.lang.Object
- edu.mit.jwi.morph.SimpleStemmer

All Implemented Interfaces:

IStemmer

Direct Known Subclasses:

WordnetStemmer
```
public class SimpleStemmer
extends Object
implements IStemmer
```
Provides simple a simple pattern-based stemming facility based on the "Rules of Detachment" as described in the morphy man page in the Wordnet distribution, which can be found at http://wordnet.princeton.edu/man/morphy.7WN.html It also attempts to strip "ful" endings. It does not search Wordnet to see if stems actually exist. In particular, quoting from that man page:

Rules of Detachment

The following table shows the rules of detachment used by Morphy. If a word ends with one of the suffixes, it is stripped from the word and the corresponding ending is added. ... No rules are applicable to adverbs.
POS Suffix Ending
- NOUN "s" ""
- NOUN "ses" "s"
- NOUN "xes" "x"
- NOUN "zes" "z"
- NOUN "ches" "ch"
- NOUN "shes" "sh"
- NOUN "men" "man"
- NOUN "ies" "y"
- VERB "s" ""
- VERB "ies" "y"
- VERB "es" "e"
- VERB "es" ""
- VERB "ed" "e"
- VERB "ed" ""
- VERB "ing" "e"
- VERB "ing" ""
- ADJ "er" ""
- ADJ "est" ""
- ADJ "er" "e"
- ADJ "est" "e"
Special Processing for nouns ending with 'ful'

Morphy contains code that searches for nouns ending with ful and performs a transformation on the substring preceding it. It then appends 'ful' back onto the resulting string and returns it. For example, if passed the nouns "boxesful", it will return "boxful".
Since:

JWI 1.0

Version:

2.4.0

Author:

Mark A. Finlayson

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`ENDING_ch`
`static String`	`ENDING_e`
`static String`	`ENDING_man`
`static String`	`ENDING_null`
`static String`	`ENDING_s`
`static String`	`ENDING_sh`
`static String`	`ENDING_x`
`static String`	`ENDING_y`
`static String`	`ENDING_z`
`static Map<POS,List<StemmingRule>>`	`ruleMap`
`static String`	`SUFFIX_ches`
`static String`	`SUFFIX_ed`
`static String`	`SUFFIX_er`
`static String`	`SUFFIX_es`
`static String`	`SUFFIX_est`
`static String`	`SUFFIX_ful`
`static String`	`SUFFIX_ies`
`static String`	`SUFFIX_ing`
`static String`	`SUFFIX_men`
`static String`	`SUFFIX_s`
`static String`	`SUFFIX_ses`
`static String`	`SUFFIX_shes`
`static String`	`SUFFIX_ss`
`static String`	`SUFFIX_xes`
`static String`	`SUFFIX_zes`
`static String`	`underscore`

Constructor Summary

Constructors
Constructor and Description

SimpleStemmer()

Constructors
Constructor and Description
`SimpleStemmer()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`List<String>`	`findStems(String word, POS pos)` Takes the surface form of a word, as it appears in the text, and the assigned Wordnet part of speech.
`protected List<String>`	`getNounCollocationRoots(String composite)` Handles stemming noun collocations.
`Map<POS,List<StemmingRule>>`	`getRuleMap()` Returns a set of stemming rules used by this stemmer.
`protected List<String>`	`getVerbCollocationRoots(String composite)` Handles stemming verb collocations.
`protected String`	`normalize(String word)` Converts all whitespace runs to single underscores.
`protected List<String>`	`stripAdjectiveSuffix(String adj)` Strips suffixes from the specified word according to the adjective rules.
`protected List<String>`	`stripNounSuffix(String noun)` Strips suffixes from the specified word according to the noun rules.
`protected List<String>`	`stripVerbSuffix(String verb)` Strips suffixes from the specified word according to the verb rules.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - underscore
```
public static final String underscore
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ches
```
public static final String SUFFIX_ches
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ed
```
public static final String SUFFIX_ed
```
    See Also:
    
    Constant Field Values
  - SUFFIX_es
```
public static final String SUFFIX_es
```
    See Also:
    
    Constant Field Values
  - SUFFIX_est
```
public static final String SUFFIX_est
```
    See Also:
    
    Constant Field Values
  - SUFFIX_er
```
public static final String SUFFIX_er
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ful
```
public static final String SUFFIX_ful
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ies
```
public static final String SUFFIX_ies
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ing
```
public static final String SUFFIX_ing
```
    See Also:
    
    Constant Field Values
  - SUFFIX_men
```
public static final String SUFFIX_men
```
    See Also:
    
    Constant Field Values
  - SUFFIX_s
```
public static final String SUFFIX_s
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ss
```
public static final String SUFFIX_ss
```
    See Also:
    
    Constant Field Values
  - SUFFIX_ses
```
public static final String SUFFIX_ses
```
    See Also:
    
    Constant Field Values
  - SUFFIX_shes
```
public static final String SUFFIX_shes
```
    See Also:
    
    Constant Field Values
  - SUFFIX_xes
```
public static final String SUFFIX_xes
```
    See Also:
    
    Constant Field Values
  - SUFFIX_zes
```
public static final String SUFFIX_zes
```
    See Also:
    
    Constant Field Values
  - ENDING_null
```
public static final String ENDING_null
```
    See Also:
    
    Constant Field Values
  - ENDING_ch
```
public static final String ENDING_ch
```
    See Also:
    
    Constant Field Values
  - ENDING_e
```
public static final String ENDING_e
```
    See Also:
    
    Constant Field Values
  - ENDING_man
```
public static final String ENDING_man
```
    See Also:
    
    Constant Field Values
  - ENDING_s
```
public static final String ENDING_s
```
    See Also:
    
    Constant Field Values
  - ENDING_sh
```
public static final String ENDING_sh
```
    See Also:
    
    Constant Field Values
  - ENDING_x
```
public static final String ENDING_x
```
    See Also:
    
    Constant Field Values
  - ENDING_y
```
public static final String ENDING_y
```
    See Also:
    
    Constant Field Values
  - ENDING_z
```
public static final String ENDING_z
```
    See Also:
    
    Constant Field Values
  - ruleMap
```
public static final Map<POS,List<StemmingRule>> ruleMap
```
- Constructor Detail
  - SimpleStemmer
```
public SimpleStemmer()
```
- Method Detail
  - getRuleMap
```
public Map<POS,List<StemmingRule>> getRuleMap()
```
    Returns a set of stemming rules used by this stemmer. Will not return a null map, but it may be empty. The lists in the map will also not be null, but may be empty.
    
    Returns:
    
    the rule map for this stemmer
    
    Since:
    
    JWI 3.5.1
  - findStems
```
public List<String> findStems(String word,
                              POS pos)
```
    Description copied from interface: IStemmer
    
    Takes the surface form of a word, as it appears in the text, and the assigned Wordnet part of speech. The surface form may or may not contain whitespace or underscores, and may be in mixed case. The part of speech may be null, which means that all parts of speech should be considered. Returns a list of stems, in preferred order. No stem should be repeated in the list. If no stems are found, this call returns an empty list. It will never return null.
    
    Specified by:
    
    findStems in interface IStemmer
    
    Parameters:
    
    word - the surface form of which to find the stem
    
    pos - the part of speech to find stems for; if null, find stems for all parts of speech
    
    Returns:
    
    the set of stems found for the surface form and part of speech combination
  - normalize
```
protected String normalize(String word)
```
    Converts all whitespace runs to single underscores. Tests first to see if there is any whitespace before converting.
    
    Parameters:
    
    word - the string to be normalized
    
    Returns:
    
    a normalized string
    
    Throws:
    
    NullPointerException - if the specified string is null
    
    IllegalArgumentException - if the specified string is empty or all whitespace
    
    Since:
    
    JWI 2.1.1
  - stripNounSuffix
```
protected List<String> stripNounSuffix(String noun)
```
    Strips suffixes from the specified word according to the noun rules.
    
    Parameters:
    
    noun - the word to be modified
    
    Returns:
    
    a list of modified forms that were constructed, or the empty list if none
    
    Throws:
    
    NullPointerException - if the specified word is null
    
    Since:
    
    JWI 1.0
  - getNounCollocationRoots
```
protected List<String> getNounCollocationRoots(String composite)
```
    Handles stemming noun collocations.
    
    Parameters:
    
    composite - the word to be modified
    
    Returns:
    
    a list of modified forms that were constructed, or the empty list if none
    
    Throws:
    
    NullPointerException - if the specified word is null
    
    Since:
    
    JWI 1.1.1
  - stripVerbSuffix
```
protected List<String> stripVerbSuffix(String verb)
```
    Strips suffixes from the specified word according to the verb rules.
    
    Parameters:
    
    verb - the word to be modified
    
    Returns:
    
    a list of modified forms that were constructed, or the empty list if none
    
    Throws:
    
    NullPointerException - if the specified word is null
    
    Since:
    
    JWI 1.0
  - getVerbCollocationRoots
```
protected List<String> getVerbCollocationRoots(String composite)
```
    Handles stemming verb collocations.
    
    Parameters:
    
    composite - the word to be modified
    
    Returns:
    
    a list of modified forms that were constructed, or an empty list if none
    
    Throws:
    
    NullPointerException - if the specified word is null
    
    Since:
    
    JWI 1.1.1
  - stripAdjectiveSuffix
```
protected List<String> stripAdjectiveSuffix(String adj)
```
    Strips suffixes from the specified word according to the adjective rules.
    
    Parameters:
    
    adj - the word to be modified
    
    Returns:
    
    a list of modified forms that were constructed, or an empty list if none
    
    Throws:
    
    NullPointerException - if the specified word is null
    
    Since:
    
    JWI 1.0

Class SimpleStemmer

Rules of Detachment

Special Processing for nouns ending with 'ful'

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

underscore

SUFFIX_ches

SUFFIX_ed

SUFFIX_es

SUFFIX_est

SUFFIX_er

SUFFIX_ful

SUFFIX_ies

SUFFIX_ing

SUFFIX_men

SUFFIX_s

SUFFIX_ss

SUFFIX_ses

SUFFIX_shes

SUFFIX_xes

SUFFIX_zes

ENDING_null

ENDING_ch

ENDING_e

ENDING_man

ENDING_s

ENDING_sh

ENDING_x

ENDING_y

ENDING_z

ruleMap

Constructor Detail

SimpleStemmer

Method Detail

getRuleMap

findStems

normalize

stripNounSuffix

getNounCollocationRoots

stripVerbSuffix

getVerbCollocationRoots

stripAdjectiveSuffix