java.lang.Object
   org.apache.lucene.analysis.TokenStream
      org.apache.lucene.analysis.TokenFilter
         org.apache.lucene.analysis.PorterStemFilter

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 extends Analyzer {
public final TokenStream tokenStream(String fieldName, Reader reader) {
return new PorterStemFilter(new LowerCaseTokenizer(reader));
}
}

 public PorterStemFilter(TokenStream in) 
{
    super(in);
    stemmer = new PorterStemmer();
}

 public final Token next(Token result) throws IOException 
{
    result = input.next(result);
    if (result != null) {
      if (stemmer.stem(result.termBuffer(), 0, result.termLength))
        result.setTermBuffer(stemmer.getResultBuffer(), 0, stemmer.getResultLength());
      return result;
    } else
      return null;
}