Assignment - Design a parking lot

[kanmaytacker]

What?

The objective is to come up with the design and implementation of a parking lot.
Follow the worksheet here to get started.

Why?
Popular LLD question.
Simple enough to implement end to end.

How?

1. Identify the classes to be needed. Add them here
2. Create a class diagram for the above classes.
3. Identify the APIs to be created from the use case diagram.

[kanmaytacker]

Submission by Akash.

• Class Diagram
• APIs
  • Admin APIs
  • Parking Attendant APIs

[Faizahmadfaiz]

Class Diagram

classDiagram

class ParkingSpotType {
   <<enumeration>>
   SMALL, MEDIUM, LARGE
}

class ParkingSpotStatus {
   <<enumeration>>
   VAILABLE, OCCUPIED, OUT_OF_SERVICE
}

class PaymentType {
   <<enumeration>>
   CASH, ONLINE, CARD
}

class VehicleType {
   <<enumeration>>
   TWO_WHEELER, THREE_WHEELER, FOUR_WHEELER, HEAVY_DUTY
}

class Gate {
   -ParkingAttendant attendant
   
   +pay(Ticket)
   +issueTicket(Vehicle)
}

Gate --o ParkingAttendant

class Vehicle {
   String vehicleNumber
   VehicleType vehicleType
}

class ParkingAttendant {
   -Ticket ticket
   -Payment payment
   -List<ParkingSpot> parkingSpots
   -SpotAllocationStrategy spotAllocationStrategy
   +receievePayment(Ticket)
   +issueTicket(Vehicle)
   +allocateSpot()
}
ParkingAttendant --o Ticket
ParkingAttendant --o Payment
ParkingAttendant --o ParkingSpot
ParkingAttendant --o SpotAllocationStrategy

class SpotAllocationStrategy {
   <<interface>>
   +allocateSpot(ParkingSpot[])
}

class RandomAllocationStrategy {
   +allocateSpot(ParkingSpot[])
}

class NearestToGateAllocationStrategy {
   +allocateSpot(ParkingSpot[])
}

SpotAllocationStrategy <-- RandomAllocationStrategy : implements
SpotAllocationStrategy <-- NearestToGateAllocationStrategy : implements
ParkingAttendant --o SpotAllocationStrategy

class Ticket {
   -ParkingSpot spot
   -String ticketId
   -Vehicle vehicle
   -DateTime entryTime
   -Double price
   
   +issue() void
}

Ticket --* Vehicle

class ParkingSpot {
   -int spotNumber
   -ParkingSpotType type
   -ParkingSpotStatus status
   -int floor
   
   +allot() void
   +deallot() void
}


class Payment {
   -PaymentType type
   
   +makePayment(Ticket)
}

Ticket --o ParkingSpot

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Api Endpoints

CRUD for Parking lot (Related to Admin)

1. Add Parking lot
   • /parkinglot
   • POST
   • BODY: {name: string, city: string, country: string, zip: number, floors: number, ...other employee details}
2. Update Parking lot
   • /parkinglot/:parkinglotId
   • PUT
   • BODY: same as above
3. Get all Parking lots
   • /parkinglot
   • GET
4. Get a parking lot
   • /parkinglot/:parkinglotId
   • GET
5. Delete a parking lot
   • /parkinglot/:parkinglotId
   • DELETE

CRUD For Parking slots (ADMIN)

1. Add a parking spot
   • /parkinglot/:parkinglotId/parkingspot
   • POST
   • BODY: type: PARKINGSPOTTYPE, status: AVAILABLE. floor: number
2. See Details of all parking spots(Used for dashboard purpose, available for attendant and customers)
   • /parkinglot/:parkinglotId/parkingspot
   • GET
3. Check status for a parking spot (For Parking attendant also)
   • /parkinglot/:parkinglotId/parkingspot/:parkingspotId
4. Update a parking spot (for attendant also)
   • /parkinglot/:parkinglotId/parkingspot/:parkingspotId
   • PUT
5. Delete a parking spot
   • /parkinglot/:parkinglotId/parkingspot/:parkingspotId
   • DELETE

Related to Customers

1. Check parking spot's status (ABOVE)
2. Make Payment
   • parkinglot/:parkinglotId/:ticketId/pay
   • POST/GET ?

Related to Parking Attendant

1. Create a ticket
   • parkinglot/:parkinglotId/ticket
   • POST
   • BODY vehicleNumber: string, entryTime: string, vehicleType: VEHICLETYPE, paymentStatus: NOT PAID, parkingSpot: int
2. Read a ticket
   • parkinglot/:parkinglotId/ticket
   • GET

[kanmaytacker]

I have updated the answers sheet here with the class diagram.
Next steps:

• Identify the differences between the two designs.
• Identify problems and possible solutions in the above design
• List the APIs required for your parking lot system

[Sowndarya011]

Class diagram for Parking Lot Problem.

[kanmaytacker]

I have merged the API design on the master branch as well.