<?phpnamespaceCron;useDateTime;/** * CRON field interface */interfaceFieldInterface{/** * Check if the respective value of a DateTime field satisfies a CRON exp * * @param DateTime $date DateTime object to check * @param string $value CRON expression to test against * * @return bool Returns TRUE if satisfied, FALSE otherwise */publicfunctionisSatisfiedBy(DateTime$date,$value);/** * When a CRON expression is not satisfied, this method is used to increment * or decrement a DateTime object by the unit of the cron field * * @param DateTime $date DateTime object to change * @param bool $invert (optional) Set to TRUE to decrement * * @return FieldInterface */publicfunctionincrement(DateTime$date,$invert=false);/** * Validates a CRON expression for a given field * * @param string $value CRON expression value to validate * * @return bool Returns TRUE if valid, FALSE otherwise */publicfunctionvalidate($value);}