docs: @Override
      public final boolean incrementToken() throws IOException {
          if (input.incrementToken()) {
              if (!keywordAttr.isKeyword()) {
                  char termBuffer[] = termAtt.buffer();
                  final int length = termAtt.length();
                  stemmer.setCurrent(new String(Arrays.copyOf(termBuffer, length)));
                  if (stemmer.stem()) {
                      final char finalTerm[] = stemmer.getCurrent().toCharArray();
                      final int newLength = finalTerm.length;
                      termAtt.copyBuffer(finalTerm, 0, newLength);
                  } else {
                      termAtt.setLength(length);
                  }
              }
              return true;
          }
          return false;
      }