Stopwords (Terrier Information Retrieval Platform 4.1 API)

java.lang.Object
- org.terrier.terms.Stopwords

All Implemented Interfaces:

TermPipeline
```
public class Stopwords
extends Object
implements TermPipeline
```
Implements stopword removal, as a TermPipeline object. Stopword list to load can be passed in the constructor or loaded from the stopwords.filename property. Note that this TermPipeline uses the system default encoding for the stopword list. Properties
- stopwords.filename - the stopword list to load. More than one stopword list can be specified, by comma-separating the filenames.
- stopwords.intern.terms - optimisation of Java for indexing: Stopwords terms are likely to appear extremely frequently in a Collection, interning them in Java will save on GC costs during indexing.
- stopwords.encoding - encoding of the file containing the stopwords, if not set defaults to trec.encoding, and if that is not set, onto the default system encoding.
Author:

Craig Macdonald

Field Summary

Fields
Modifier and Type	Field and Description
`protected static boolean`	`INTERN_STOPWORDS`
`protected TermPipeline`	`next` The next component in the term pipeline.
`protected gnu.trove.THashSet<String>`	`stopWords` The hashset that contains all the stop words.

Constructor Summary

Constructors
Constructor and Description
`Stopwords(TermPipeline _next)` Makes a new stopword termpipeline object.
`Stopwords(TermPipeline _next, String StopwordsFile)` Makes a new stopword term pipeline object.
`Stopwords(TermPipeline _next, String[] StopwordsFiles)` Makes a new stopword term pipeline object.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clear()` Clear all stopwords from this stopword list object.
`boolean`	`isStopword(String t)` Returns true is term t is a stopword
`void`	`loadStopwordsList(String stopwordsFilename)` Loads the specified stopwords file.
`void`	`loadStopwordsList(String[] StopwordsFiles)` Loads the specified stopwords files.
`void`	`processTerm(String t)` Checks to see if term t is a stopword.
`boolean`	`reset()` This method implements the specific rest option needed to implements query or doc oriented policy.

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

- Field Detail
  - INTERN_STOPWORDS
```
protected static final boolean INTERN_STOPWORDS
```
  - next
```
protected final TermPipeline next
```
    The next component in the term pipeline.
  - stopWords
```
protected final gnu.trove.THashSet<String> stopWords
```
    The hashset that contains all the stop words.
- Constructor Detail
  - Stopwords
```
public Stopwords(TermPipeline _next)
```
    Makes a new stopword termpipeline object. The stopwords file is loaded from the application setup file, under the property stopwords.filename.
    
    Parameters:
    _next - TermPipeline the next component in the term pipeline.
  - Stopwords
```
public Stopwords(TermPipeline _next,
         String StopwordsFile)
```
    Makes a new stopword term pipeline object. The stopwords file(s) are loaded from the filename parameter. If the filename is not absolute, it is assumed to be in TERRIER_SHARE. StopwordsFile is split on \s*,\s* if a comma is found in StopwordsFile parameter.
    
    Parameters:
    _next - TermPipeline the next component in the term pipeline
    StopwordsFile - The filename(s) of the file to use as the stopwords list. Split on comma, and passed to the (TermPipeline,String[]) constructor.
  - Stopwords
```
public Stopwords(TermPipeline _next,
         String[] StopwordsFiles)
```
    Makes a new stopword term pipeline object. The stopwords file(s) are loaded from the filenames array parameter. The non-existance of any file is not enough to stop the system. If a filename is not absolute, it is is assumed to be in TERRIER_SHARE.
    
    Parameters:
    _next - TermPipeline the next component in the term pipeline
    StopwordsFiles - Array of filenames of stopword lists.
    Since:
    
    1.1.0
- Method Detail
  - loadStopwordsList
```
public void loadStopwordsList(String[] StopwordsFiles)
```
    Loads the specified stopwords files. Calls loadStopwordsList(String).
    
    Parameters:
    StopwordsFiles - Array of filenames of stopword lists.
    Since:
    
    1.1.0
  - loadStopwordsList
```
public void loadStopwordsList(String stopwordsFilename)
```
    Loads the specified stopwords file. Used internally by Stopwords(TermPipeline, String[]). If a stopword list filename is not absolute, then ApplicationSetup.TERRIER_SHARE is appended.
    
    Parameters:
    stopwordsFilename - The filename of the file to use as the stopwords list.
  - clear
```
public void clear()
```
    Clear all stopwords from this stopword list object.
    
    Since:
    
    1.1.0
  - isStopword
```
public boolean isStopword(String t)
```
    Returns true is term t is a stopword
  - processTerm
```
public void processTerm(String t)
```
    Checks to see if term t is a stopword. If so, then the TermPipeline is exited. Otherwise, the term is passed on to the next TermPipeline object. This is the TermPipeline implementation part of this object.
    
    Specified by:
    
    processTerm in interface TermPipeline
    
    Parameters:
    t - The term to be checked.
  - reset
```
public boolean reset()
```
    This method implements the specific rest option needed to implements query or doc oriented policy.
    
    Specified by:
    
    reset in interface TermPipeline
    
    Returns:
    results of the operation

Class Stopwords

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INTERN_STOPWORDS

next

stopWords

Constructor Detail

Stopwords

Stopwords

Stopwords

Method Detail

loadStopwordsList

loadStopwordsList

clear

isStopword

processTerm

reset