abonnementmønster

An abonnementmønster, or subscription pattern, refers to a design pattern in software development that allows an object (the subject) to maintain a list of its dependents (observers) and automatically notifies them of any state changes. This pattern is a fundamental concept in event-driven programming and facilitates loose coupling between objects.

The core idea is that an observer object registers itself with a subject object. When the subject's state changes, it iterates through its list of registered observers and calls a specific method on each of them, typically passing information about the change. This allows multiple objects to react to a single event without the subject needing to know the specifics of each observer's implementation.

Common use cases for the subscription pattern include user interface updates, where changes in data trigger visual modifications in various UI elements, or in real-time data processing, where multiple components need to be alerted when new data arrives. The pattern promotes a flexible and extensible architecture, as new observers can be added or removed without modifying the subject's code. However, care must be taken to manage the observer list to prevent memory leaks, especially in long-running applications. The pattern is also known by other names such as publish-subscribe or observer pattern.