Observer Pattern
- Computer Science Department
The Observer pattern is a behavioral design pattern in object-oriented programming (OOP) that defines a one-to-many dependency between objects. It allows multiple observers (subscribers) to be notified and updated automatically when the state of a subject (publisher) object changes. The Observer pattern promotes loose coupling between objects, making them highly reusable and modular.
In the Observer pattern, there are three key components:
Subject (Observable): Represents the object being observed. It maintains a list of observers and provides methods to register, remove, and notify observers of any state changes.
Observer: Defines an interface that observers implement to receive updates from the subject. Typically, the interface includes a method like
update()that is called by the subject when a state change occurs.Concrete Observers: Implement the Observer interface and provide specific behavior to respond to state changes in the subject. Each concrete observer can register with the subject to receive notifications
