private static boolean isOneLineFeed(PsiElement e) {
    if (e == null) return false;
    if (!PsiImplUtil.isWhiteSpaceOrNls(e)) return false;

    final String text = e.getText();
    final int i = text.indexOf('\n');
    return i >= 0 && i == text.lastIndexOf('\n');
  }
private static boolean isOneLineFeed(PsiElement e)