weka.core.stemmers

## Class SnowballStemmer

- java.lang.Object
- - weka.core.stemmers.SnowballStemmer

- All Implemented Interfaces:
    java.io.Serializable, OptionHandler, RevisionHandler, Stemmer

      public class SnowballStemmer
      extends java.lang.Object
      implements Stemmer, OptionHandler

  A wrapper class for the Snowball stemmers. Only available if the Snowball classes are in the classpath.
  If the class discovery is not dynamic, i.e., the property 'UseDynamic' in the props file 'weka/gui/GenericPropertiesCreator.props' is 'false', then the property 'org.tartarus.snowball.SnowballProgram' in the 'weka/gui/GenericObjectEditor.props' file has to be uncommented as well. If necessary you have to discover and fill in the snowball stemmers manually. You can use the 'weka.core.ClassDiscovery' for this:
  java weka.core.ClassDiscovery org.tartarus.snowball.SnowballProgram org.tartarus.snowball.ext
  For more information visit these web sites:
  http://weka.wikispaces.com/Stemmers
  http://snowball.tartarus.org/

  Valid options are:

       -S <name>
        The name of the snowball stemmer (default 'porter').
        available stemmers:
           danish, dutch, english, finnish, french, german, italian,
           norwegian, porter, portuguese, russian, spanish, swedish

  Version:
    $Revision: 10203 $
  Author:
    FracPete (fracpete at waikato dot ac dot nz)
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static java.lang.String` | `PACKAGE` the package name for snowball.
    `static java.lang.String` | `PACKAGE_EXT` the package name where the stemmers are located.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `SnowballStemmer()` initializes the stemmer ("porter").
    `SnowballStemmer(java.lang.String name)` initializes the stemmer with the given stemmer.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.lang.String[]` | `getOptions()` Gets the current settings of the classifier.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `java.lang.String` | `getStemmer()` returns the name of the current stemmer, null if none is set.
    `java.lang.String` | `globalInfo()` Returns a string describing the stemmer.
    `static boolean` | `isPresent()` returns whether Snowball is present or not, i.e.
    `java.util.Enumeration<Option>` | `listOptions()` Returns an enumeration describing the available options.
    `static java.util.Enumeration<java.lang.String>` | `listStemmers()` returns an enumeration over all currently stored stemmer names.
    `static void` | `main(java.lang.String[] args)` Runs the stemmer with the given options.
    `void` | `setOptions(java.lang.String[] options)` Parses the options.
    `void` | `setStemmer(java.lang.String name)` sets the stemmer with the given name, e.g., "porter".
    `java.lang.String` | `stem(java.lang.String word)` Returns the word in its stemmed form.
    `java.lang.String` | `stemmerTipText()` Returns the tip text for this property.
    `java.lang.String` | `toString()` returns a string representation of the stemmer.

    - ### Methods inherited from class java.lang.Object

      `equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### PACKAGE

          public static final java.lang.String PACKAGE

      the package name for snowball.
      See Also:
        Constant Field Values

    - #### PACKAGE_EXT

          public static final java.lang.String PACKAGE_EXT

      the package name where the stemmers are located.
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### SnowballStemmer

          public SnowballStemmer()

      initializes the stemmer ("porter").

    - #### SnowballStemmer

          public SnowballStemmer(java.lang.String name)

      initializes the stemmer with the given stemmer.
      Parameters:
        `name` - the name of the stemmer

  - ### Method Detail

    - #### globalInfo

          public java.lang.String globalInfo()

      Returns a string describing the stemmer.
      Returns:
        a description suitable for displaying in the explorer/experimenter gui

    - #### listOptions

          public java.util.Enumeration<Option> listOptions()

      Returns an enumeration describing the available options.
      Specified by:
        `listOptions` in interface `OptionHandler`
      Returns:
        an enumeration of all the available options.

    - #### setOptions

          public void setOptions(java.lang.String[] options)
                          throws java.lang.Exception

      Parses the options.

      Valid options are:

           -S <name>
            The name of the snowball stemmer (default 'porter').
            available stemmers:
               danish, dutch, english, finnish, french, german, italian,
               norwegian, porter, portuguese, russian, spanish, swedish

      Specified by:
        `setOptions` in interface `OptionHandler`
      Parameters:
        `options` - the options to parse
      Throws:
        `java.lang.Exception` - if parsing fails

    - #### getOptions

          public java.lang.String[] getOptions()

      Gets the current settings of the classifier.
      Specified by:
        `getOptions` in interface `OptionHandler`
      Returns:
        an array of strings suitable for passing to setOptions

    - #### isPresent

          public static boolean isPresent()

      returns whether Snowball is present or not, i.e. whether the classes are in the classpath or not
      Returns:
        whether Snowball is available

    - #### listStemmers

          public static java.util.Enumeration<java.lang.String> listStemmers()

      returns an enumeration over all currently stored stemmer names.
      Returns:
        all available stemmers

    - #### getStemmer

          public java.lang.String getStemmer()

      returns the name of the current stemmer, null if none is set.
      Returns:
        the name of the stemmer

    - #### setStemmer

          public void setStemmer(java.lang.String name)

      sets the stemmer with the given name, e.g., "porter".
      Parameters:
        `name` - the name of the stemmer, e.g., "porter"

    - #### stemmerTipText

          public java.lang.String stemmerTipText()

      Returns the tip text for this property.
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### stem

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

      Returns the word in its stemmed form.
      Specified by:
        `stem` in interface `Stemmer`
      Parameters:
        `word` - the unstemmed word
      Returns:
        the stemmed word

    - #### toString

          public java.lang.String toString()

      returns a string representation of the stemmer.
      Overrides:
        `toString` in class `java.lang.Object`
      Returns:
        a string representation of the stemmer

    - #### getRevision

          public java.lang.String getRevision()

      Returns the revision string.
      Specified by:
        `getRevision` in interface `RevisionHandler`
      Returns:
        the revision

    - #### main

          public static void main(java.lang.String[] args)

      Runs the stemmer with the given options.
      Parameters:
        `args` - the options