code: private String filterTokens(String article) {
          Iterator<String> filteredTokens = IteratorFactory.tokenize(article);
          StringBuilder sb = new StringBuilder(article.length());
          while (filteredTokens.hasNext()) {
              sb.append(filteredTokens.next());
              if (filteredTokens.hasNext())
                  sb.append(" ");
          }
          return sb.toString();
      }
docs: Removes any tokens not allowed by the {@link
  edu.ucla.sspace.text.TokenFilter} in the article.