private static int calcParensBalance(Document document, EditorHighlighter highlighter, int rangeStart, int rangeEnd){
    LOG.assertTrue(0 <= rangeStart);
    LOG.assertTrue(rangeStart <= rangeEnd);
    LOG.assertTrue(rangeEnd <= document.getTextLength());

    HighlighterIterator iterator = highlighter.createIterator(rangeStart);
    int balance = 0;
    while(!iterator.atEnd() && iterator.getStart() < rangeEnd){
      IElementType tokenType = iterator.getTokenType();
      if (tokenType == JavaTokenType.LPARENTH){
        balance++;
      }
      else if (tokenType == JavaTokenType.RPARENTH){
        balance--;
      }
      iterator.advance();
    }
    return balance;
  }
private static int calcParensBalance(Document document, EditorHighlighter highlighter, int rangeStart, int rangeEnd)