Design Restaurant Management System
Design a Restaurant Management System that handles table reservations, order placement, billing, and menu management using object-oriented design.
A Restaurant Management System is software that helps manage the day-to-day operations of a restaurant, including table reservations, order taking, kitchen coordination, billing, menu updates, and staff management.
It streamlines workflows, improves customer service, and increases overall efficiency.
In this chapter, we will explore the low-level design of a restaurant management system in detail.
Lets start by clarifying the requirements:
1. Clarifying Requirements
Before starting the design, it's important to ask thoughtful questions to uncover hidden assumptions and better define the scope of the system.
Here is an example of how a conversation between the candidate and the interviewer might unfold:
Candidate: What are the primary actors in this system? Are we designing a customer-facing app for ordering, or an internal system for staff management
Interviewer: Let's focus on the internal system for staff (Waiters, Chefs) to manage orders and billing. Customer interaction is out of scope.
Candidate: Should the system handle table reservations in advance, or only manage walk-in customers and their current table status?
Interviewer: Good question. For now, let’s focus on the core workflow: taking an order, preparing it, serving it, and generating a bill. We can assume tables are managed in real-time (available, occupied), but a full reservation feature is not required.
Candidate: Should the system track inventory for menu items? For example, knowing if we're out of a certain ingredient.
Interviewer: That's a great extension, but let’s keep it out of scope for this interview. Assume all menu items are always available.
Candidate: How are orders assigned to chefs?
Interviewer: Let's assume a simple mechanism for now, like assigning an order to the first available chef.
Candidate: How does a waiter know when an order item is ready for pickup from the kitchen?
Interviewer: The waiter who takes the order should be notified specifically when an item they are responsible for is ready for pickup.
Candidate: How should payments be handled? Do we need to integrate with a payment gateway for credit cards, or just calculate the final bill?
Interviewer: Just focus on calculating the final bill. The bill should be flexible enough to include things like taxes or service charges. Assume payment processing is handled by a separate system.
After gathering the details, we can summarize the key system requirements.
1.1 Functional Requirements
- Staff Management: The system should support different staff roles, specifically Waiters and Chefs.
- Table Management: The system must track the status of each table (e.g., AVAILABLE, OCCUPIED).
- Menu Management: The system must maintain a menu of items, each with a name and a price.
- Order Management: Waiters can create an order for a specific table. The system must track the status of each individual order item.
- Kitchen Workflow: Chefs receive and prepare orders. The system must notify the correct waiter when an order item is ready for pickup.
- Billing: The system must be able to generate a bill for a given order. The bill calculation should be flexible enough to dynamically add charges like taxes and service fees.
1.2 Non-Functional Requirements
- Modularity: The design should follow solid object-oriented principles with clear separation of concerns.
- Extensibility: The design should be easy to extend to allow future enhancements. For example, it should be easy to add new types of bill charges (e.g., discounts) or new order item states without modifying existing code.
- Maintainability: The code should be clean, readable, and easy to maintain, leveraging appropriate design patterns to solve common problems.
- Concurrency: The system should be designed to handle multiple orders and staff interactions concurrently without data corruption.
- Clarity: The system should provide clear console output to demonstrate the workflow, such as state changes and notifications.