Use Cases of Observer Method Design Pattern

Basically, this pattern is widely used in software development for implementing distributed event handling systems. So let’s see some common use cases for the Observer Pattern:

• GUI Systems: In graphical user interface (GUI) development, the Observer Pattern is frequently used. For example, a button click event can be observed by multiple UI components, such as listeners or observers, that need to respond to the button click.
• Event Handling in Libraries/Frameworks: Many programming libraries and frameworks use the Observer Pattern to manage events. For instance, in Java Swing, the observer pattern is employed to handle events generated by user interactions with graphical components.
• Distributed Systems: Observer Pattern is useful in distributed systems where different parts of the system need to stay synchronized. When one part of the system changes state, it notifies its observers, which could be located remotely. This is essential for building loosely coupled and scalable systems.
• Model-View-Controller (MVC) Architecture: MVC is a widely used architectural pattern, and the Observer Pattern is a fundamental part of it. The model notifies its observers (views) when its state changes, and the views update accordingly. This separation of concerns makes the system more modular and easier to maintain.
• Stock Market Applications: In financial applications, the Observer Pattern can be used to implement real-time stock market data updates. Various components (observers) interested in stock prices can subscribe to updates, and when the stock prices change, all the subscribers are notified.
• Logging and Monitoring Systems: In logging and monitoring applications, the Observer Pattern can be used to notify different monitoring components when certain events or thresholds are reached. This allows for flexible and extensible monitoring systems.
• Chat Applications: Chat applications can use the Observer Pattern to notify users about new messages. When a user sends a message, all other users who are part of the conversation can be notified and update their chat interfaces accordingly.
• Custom Events in Software Systems: When a software system needs a custom event system where certain actions trigger responses in other parts of the system, the Observer Pattern can be employed to manage these custom events.

Observer Design Pattern is a behavioral design pattern where an object, known as the subject, maintains a list of its dependents, called observers, that are notified of any changes in the subject’s state. This pattern is often used to implement distributed event handling systems.