In this eighteenth episode of the Mastering Low-Level Design series, we explore the State Design Pattern — a behavioral design pattern that allows an object to alter its behavior when its internal state changes, appearing as if it changed its class.
The State pattern is perfect for scenarios where objects go through multiple states — like vending machines, media players, or user sessions. Instead of cluttering your code with conditionals, you delegate behavior to state-specific classes, making your code cleaner, more modular, and easier to extend.
📄 Resource: https://github.com/singalhimanshu/mastering-lld-series-yt
📚 All Resources for this series: https://github.com/singalhimanshu/mastering-lld-series-yt
📺 Playlist: https://youtube.com/playlist?list=PLX0iyO9CrCF0uuhYRRx0Z6E_YUwNJ9FV_&si=vSg2MCzoJBTYEPZN
🔍 What’s covered in this video:
What is the State Design Pattern
Real-world analogy and use cases (e.g., vending machines, traffic lights, game states)
Problems with condition-heavy logic and messy state transitions
Java implementation using a Vending Machine
Benefits: Clean code, Open/Closed Principle, separation of responsibilities
When to use State in multi-mode objects and workflow systems
Best practices for implementation
This video is perfect for Java developers, system design interview candidates, and backend engineers looking to master behavioral design patterns to build cleaner and more extensible systems.
