Design Restaurant Management

Tables, orders, kitchen queue, and billing.

Advanced16 min read

Read these first

Design Hotel Booking

Why this matters

Assign tables by party size and availability
Scope — what "Table assignment" covers inside Restaurant Management and what it does not
Scope — what "Order pipeline" covers inside Restaurant Management and what it does not
Scope — what "Bill split" covers inside Restaurant Management and what it does not
Booking problems test inventory, overlap, and concurrent holds.

BookingService

Resourceroom, seat, table

TimeSlotstart, end, capacity

Reservationstatus, userId

Typical CampusOS booking: resource, slot, reservation, user.

CampusOS context

CampusOS is the fictional smart-campus platform used across this track. Treat this module as a real product slice:

Context

Belongs to CampusOS — same naming and design vocabulary as parking, library, and booking modules
Scope is one JVM — persistence is in-memory or behind a repository interface
Goal is a class diagram + core Java that an interviewer can follow in 35–45 minutes
Extension paragraph at the end links to System Design when scale exceeds one process

Requirements snapshot

Functional requirements

Assign tables by party size and availability
Waiter creates order; kitchen receives items by course
Order states: placed → preparing → served → billed
Split bill by item or equally among diners
Menu items with modifiers (extra cheese, no onion)

Non-functional requirements

Single JVM, in-process design for this LLD article
Core flows testable with in-memory repositories
Extension points for new rules without editing central god classes
Clear public API on facade/service layer
CampusOS extension links to System Design when scale demands distribution

Overview

This CampusOS module designs Restaurant Management as a production-ready in-process service. Read requirements point-by-point before drawing classes.

Requirements

Points to cover

Assign tables by party size and availability
Waiter creates order; kitchen receives items by course
Order states: placed → preparing → served → billed
Split bill by item or equally among diners
Menu items with modifiers (extra cheese, no onion)

Table assignment

Points to cover

Scope — what "Table assignment" covers inside Restaurant Management and what it does not
Classes — name 2–4 classes/interfaces responsible for this slice
Flow — step-by-step: trigger → validation → state change → side effect
Edge cases — invalid input, concurrent access, empty state, timeout
Pattern — Strategy, State, Observer, or Facade if it fits naturally
Test hook — one scenario an interviewer will ask you to walk through

Order pipeline

Points to cover

Scope — what "Order pipeline" covers inside Restaurant Management and what it does not
Classes — name 2–4 classes/interfaces responsible for this slice
Flow — step-by-step: trigger → validation → state change → side effect
Edge cases — invalid input, concurrent access, empty state, timeout
Pattern — Strategy, State, Observer, or Facade if it fits naturally
Test hook — one scenario an interviewer will ask you to walk through

Bill split

Points to cover

Scope — what "Bill split" covers inside Restaurant Management and what it does not
Classes — name 2–4 classes/interfaces responsible for this slice
Flow — step-by-step: trigger → validation → state change → side effect
Edge cases — invalid input, concurrent access, empty state, timeout
Pattern — Strategy, State, Observer, or Facade if it fits naturally
Test hook — one scenario an interviewer will ask you to walk through

Java

// CampusOS — RestaurantManagement facade (keep thin)
public final class RestaurantManagementService {
    private final RestaurantManagementRepository repository;

    public RestaurantManagementService(RestaurantManagementRepository repository) {
        this.repository = repository;
    }

    /** Orchestrate: validate → domain rules → persist → return result */
    public Result handle(Request request) {
        request.validate();
        var domain = DomainModel.from(request);
        domain.applyRules();
        return repository.save(domain);
    }
}

Quick recall

Everything you need if you only revisit this box.

Requirements — review this slice before mock interviews.
Table assignment — review this slice before mock interviews.
Order pipeline — review this slice before mock interviews.
Bill split — review this slice before mock interviews.

CampusOS extension

When this outgrows one JVM

Shard inventory or state by campus ID or geographic region
Push notifications, payments, and search to dedicated services (System Design track)
Use message queues for async side effects (email, analytics)
The class diagram you drew here becomes one box on the HLD architecture diagram

Test yourself

Answer these before moving on — recall is what makes it stick.