public function equals($objcDateTime = null)
    {
        if ($objcDateTime == null) {
            return false;
        }
        
        $diff_year = $this->adate['year'] - $objcDateTime->adate['year'];
        $diff_mon = $this->adate['mon'] - $objcDateTime->adate['mon'];
        $diff_day = $this->adate['mday'] - $objcDateTime->adate['mday'];
        
        if ($diff_year > 0) {
            return 1;
        }
        elseif ($diff_year < 0) {
            return -1;
        }
        elseif ($diff_mon > 0) {
            return 1;
        }
        elseif ($diff_mon < 0) {
            return -1;
        }
        elseif ($diff_day > 0) {
            return 1;
        }
        elseif ($diff_day < 0) {
            return -1;
        }
        else {
            return 0;
        }
    }