Hotel Reservations

Requirements

• Search for rooms of a given type that are free for every night in a date range
• Book a specific room for a guest, never overlapping another active booking for that room
• Cancel a booking, freeing its nights for others
• Check a guest in and out, allowing only the transitions that make sense
• Calculate the cost of a stay from a nightly rate that can differ on particular nights, such as weekends

Assumptions you may make

• One hotel and a single process
• A stay covers whole nights: arriving on the 3rd and leaving on the 5th is two nights
• Two clerks may try to book the same room at the same moment; exactly one must succeed

Things the brief expects to exist

Candidates, not a design. How they relate is yours to decide.

ReservationService

The front desk's entry point for searching, booking and cancelling

Room

Knows its number and type, and owns its calendar

RoomCalendar

Holds one room's bookings and refuses overlapping ones

Booking

Records a guest's stay in a room and its lifecycle status

DateRange

A half-open span of nights that can test overlap with another

RatePlan

Gives the rate for a room type on a particular night

Guest

Identifies the person staying

What this exercise is teaching

• Represent a stay so that back-to-back bookings never appear to clash
• Make checking availability and claiming a room a single indivisible step
• Keep the rate rules separate from the booking logic
• Make the booking lifecycle explicit, so an impossible transition is rejected rather than ignored

Once it works, make it survive these

• Book by room type and assign the actual room at check-in
• Book several rooms for one party, all or nothing
• Add a cancellation rule that charges the first night when cancelling within 24 hours