Low Level Design Car Rental System

Requirements

• Show cars available for rent

• Show stores based on location

• Each Store has cars available for rent

• In the future, this rental company may plan to start rents SUVs, trucks etc

• The user can reserve a vehicle by giving a security deposit and required docs

• The final amount to be paid/returned is decided in the end

User Flows

Happy Flow:

1. User Registration:

   • User registers with personal information.

2. Browse and Reserve:

   • User selects a location.

   • User browses available cars (including future SUVs/trucks).

   • User reserves a car, pays a deposit, and provides necessary documents.

3. Payment & Confirmation:

   • System processes payment.

   • User receives booking confirmation.

4. Pick-Up & Usage:

   • User picks up the car and enjoys the rental.

5. Return & Inspection:

   • User returns the car.

   • Car inspection determines final charges.

6. Feedback:

   • User provides feedback and reviews.

Unhappy Flow (Cancellation):

1. Booking Cancellation:

   • User cancels the booking, and a refund is processed.

Edge Cases:

1. Car Unavailability:

   • If a selected car becomes unavailable, alternatives are suggested.

2. Late Return:

   • Late return incurs extra charges.

3. Damage Dispute:

   • Disputes over car damage are facilitated.

4. Emergency Assistance:

   • User can seek assistance in case of car problems.

Object/Model Identification (Building bottom up)

• Vehicle

  

  

• VehicleInventoryManager manages vehicles

  • 

• The store has a Location, has its own VehicleInventoryManager,maintains a list of reservations

  

• Location

  

• Reservation: has User object and related info

  

  • 

• User

  

• VehicleRentalSystem:

  • getStore takes in a Location object and returns list of stores

  • instead of having a user List here we can have reference to different UserManager that manage related things it can also have a reference to VehicleInventory Management in case we need to search by vehicle irrespective of the location

    

Main

• Bill , generated against a Reservation

  

• Payment can have Payment Strategy to pay the bill

  

UML