An online store has a product that is out of stock. Customers want to be notified when it is back. You could have the store object constantly checking with customer objects, but that creates a tight coupling.
To dive into design patterns, follow these steps: dive into design patterns pdf github
While the official full version is a paid ebook available on Refactoring.Guru , you can find various related resources, including partial versions, community-driven code implementations, and similar papers hosted on GitHub: Core Resources and Repositories An online store has a product that is out of stock
: Emphasizes when and why to use a pattern, not just how to write it. you can find various related resources