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Observer Pattern

A behavioral design pattern that lets you define a subscription mechanism to notify multiple objects about any events that happen to the object they're observing.

Categorydev

Overview

The Observer pattern is the foundation of event-driven programming. It involves a 'Subject' (the object being observed) and 'Observers' (the objects that want to be notified of changes).

Key Concepts

  • Subject: Maintains a list of observers and notifies them of state changes.
  • Observer: Defines an updating interface for objects that should be notified of changes in a subject.

Real-world Examples

  • UI event listeners (e.g., button clicks).
  • Pub/Sub messaging systems.
  • Model-View-Controller (MVC) architecture.

Related Terms

Behavioral PatternsReactive Programming