Katkat
Back

Design an object-oriented parking lot system

UberSoftware Engineer · Technical Screen
MediumSoftware EngineerTechnical ScreenSoftware Engineering Fundamentals

Last updated

This question evaluates object-oriented design competency, including class modeling, responsibility assignment, relationships (inheritance and composition), and familiarity with design patterns and SOLID principles for representing constraints like spot sizes and vehicle types.

Design an object-oriented model for a parking lot management system.

Requirements:

  • The parking lot has multiple levels; each level has multiple parking spots.
  • Each spot has a size: small, medium, or large.
  • Vehicles can be of different types: motorcycle, car, or bus/truck.
  • A vehicle can only be parked in a spot of a compatible size. A bus or truck may require multiple adjacent large spots.
  • The system must support:
  • Vehicle entry: find and reserve an appropriate spot (or group of spots) for an incoming vehicle.
  • Vehicle exit: free the spot(s) and calculate the parking fee based on time parked.
  • Query operations: report the number of available spots per size and per level, and whether the lot is full.

Assumptions:

  • Ignore distributed systems concerns; you are designing an in-process object-oriented model, not a networked service.
  • You may assume time and payment processing are handled by simple helper components.

Describe:

  • The main classes, their responsibilities, and key attributes.
  • The relationships between classes (inheritance, composition, etc.).
  • The main methods needed to support the above operations.
  • Any design patterns or principles (for example, SOLID) you apply.