code: private String getWord(String[] nodeFeatures) {
          String word = nodeFeatures[formIndex];
          // Filter if neccessary.
          if (filter != null && !filter.accept(word))
              return IteratorFactory.EMPTY_TOKEN;
          return word;
      }
docs: Returns a string representation of the word for a given node in the
  dependency parse tree.  First, the original word is filtered and if the
  word is not accepted, the empty string is returned.  Accepted words will
  then be stemmed if either a lemma is provided by the parser or a {@link
  Stemmer} is provided with a preference given to the parser provided
  lemma.  If neither case holds, the original term is returned.