EventDispatcher

An EventDispatcher is a fundamental design pattern used in software development to manage and distribute events. It acts as a central hub that allows different parts of an application to communicate with each other without direct coupling. The core idea is that one object, the EventDispatcher, holds a list of listeners or subscribers that are interested in specific types of events. When an event occurs, the EventDispatcher is notified and then iterates through its list of listeners, notifying each one that is registered for that particular event type.

This pattern promotes a loosely coupled architecture. Instead of a component needing to know about every other component that might be interested in its actions, it simply dispatches an event. Similarly, components that want to react to an event don't need to know the source of the event; they just register their interest with the EventDispatcher. This makes the system more modular, flexible, and easier to maintain and extend.

Key components of an EventDispatcher system include the dispatcher itself, events, and listeners. Events represent something that has happened, such as a button click, a data update, or a network response. Listeners are objects or functions that register with the dispatcher to be notified when specific events occur. The dispatcher is responsible for managing these registrations and for broadcasting events to the appropriate listeners. Many programming languages and frameworks provide built-in support or libraries for implementing event dispatching mechanisms.