Object-Oriented Design• Patterns: Factory, Observer

Restaurant

Medium

Problem Summary

Design a Restaurant management system handling table reservations, dining orders, chef notifications, and bills.

Functional Scope

Support dynamic table status mapping (Free, Reserved, Occupied).
Process orders containing multiple menu items and customize chef alerts.
Calculate checks with optional tax, service fee, and discount vouchers.

Entity-Relationship (ER) Schema

Restaurant [1] <---> [*] Table
Table [1] <---> [0..1] Order
Order [1] <---> [*] MenuItem
Order [1] <---> [1] Bill

Design Approach

Table booking must be thread-safe to prevent double reservation. Use Observer to push active kitchen order updates directly to the chefs' display.

Core Classes & Models

Table (Capacity, State)Order (List of items, table reference, status)MenuItem (Name, Price, Category)Bill (Calculations, payments status)

Code Blueprint

public enum TableStatus { FREE, RESERVED, OCCUPIED }
public class Table {
    private TableStatus status = TableStatus.FREE;
    public synchronized boolean book() { return true; }
}