Class PorterStemFilter

Transforms the token stream as per the Porter stemming algorithm.

Note: the input to the stemming filter must already be in lower case, so you will need to use LowerCaseFilter or LowerCaseTokenizer farther down the Tokenizer chain in order for this to work properly!

To use this filter with other analyzers, you'll want to write an Analyzer class that sets up the TokenStream chain as you want it. To use this with LowerCaseTokenizer, for example, you'd write an analyzer like this:

class MyAnalyzer : Analyzer {
  protected override TokenStreamComponents CreateComponents(string fieldName, TextReader reader) {
    Tokenizer source = new LowerCaseTokenizer(version, reader);
    return new TokenStreamComponents(source, new PorterStemFilter(source));
  }
}

Note: This filter is aware of the KeywordAttribute. To prevent certain terms from being passed to the stemmer IsKeyword should be set to

true