State Pattern Powers Clean Order Lifecycle in E-Commerce System Design

A software design tutorial on DEV Community demonstrates how to implement the State design pattern in a Java-based e-commerce Order Management System. The system models an order's lifecycle across four sequential stages: Created, Paid, Shipped, and Delivered. Each state class encapsulates its own business rules, blocking illegal transitions such as shipping an unpaid order without relying on if/else or switch statements. The central Order context delegates all actions to the current state object, which then handles validation and triggers the next transition. This approach keeps the codebase modular and easier to maintain by distributing responsibility across individual state classes.