Consequences and Comparison
Understand the Reactor pattern by exploring how it improves event-driven applications in C. Learn about its single-responsibility principle benefits, open-closed principle adherence, and comparison with the Observer pattern, focusing on notification mechanisms, cohesion, and modular event handling.
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Comparison of Reactor and Observer
Although the mechanisms used to implement them are related, there are differences between these two
patterns. The main difference is in the notification mechanism. As a Subject changes its state in an
Observer implementation, all its dependents (observers) are notified. In a Reactor implementation, this relationship is one to one – a detected event leads the Reactor to notify exactly one dependent
(EventHandler).
One typical liability of the Observer pattern is that the cohesion of the subject is lowered; besides serving its central purpose, a subject also takes on the responsibility of managing and notifying observers. With this respect, a Reactor differs significantly as its whole raison d’être is to dispatch events to its registered handlers.
Consequences
The main consequences of applying the Reactor ...