public function getValue($type = self::UNIX_TIMESTAMP)
    {
        switch ($type) {
            case self::UNIX_TIMESTAMP:
                $seconds = $this->convertJdToUnix($this->day_count);
                if ($seconds === false) {
                    /*
                     * We get false if the Julian Day Count is outside the range
                     * of a UNIX timestamp.
                     */
                    return false;
                } else {
                    return $seconds + $this->seconds;
                }
                break;
            case self::EXIF_STRING:
                list ($year, $month, $day) = $this->convertJdToGregorian($this->day_count);
                $hours = (int) ($this->seconds / 3600);
                $minutes = (int) ($this->seconds % 3600 / 60);
                $seconds = $this->seconds % 60;
                return sprintf('%04d:%02d:%02d %02d:%02d:%02d', $year, $month, $day, $hours, $minutes, $seconds);
            case self::JULIAN_DAY_COUNT:
                return $this->day_count + $this->seconds / 86400;
            default:
                throw new PelInvalidArgumentException(
                    'Expected UNIX_TIMESTAMP (%d), ' . 'EXIF_STRING (%d), or ' . 'JULIAN_DAY_COUNT (%d) for $type, got %d.',
                    self::UNIX_TIMESTAMP,
                    self::EXIF_STRING,
                    self::JULIAN_DAY_COUNT,
                    $type
                );
        }
    }