Write pseudocode for dependency checks and merge procedures (as used in Bayou) suitable for a simple room-booking application.

Question

What will be an ideal response?

Answer 1

```
Operation: room.book(booking).
let timeSlot = booking.getPreferredTimeSlot();
Dependency check:
existingBooking = room.getBooking(timeSlot);
if (existingBooking != null) return “conflict” else return “no conflict”;
Merge procedure:
existingBooking = room.getBooking(timeSlot);
// Choose the booking that should take precedence over the other if (greatestPriority(existingBooking, booking) == booking)
then { room.setBooking(timeSlot, booking); existingBooking.setStatus(“failed”);}
else {booking.setStatus(“failed”);}
```
– in a more sophisticated version of this scheme, bookings have alternative time slots. When a booking cannot be made at the preferred time slot, the merge procedure runs through the alternative time slots and only reports failure if none is available. Similarly, alternative rooms could be tried.