Consequences of Using the Observer Pattern
Understand how the Observer pattern enables loose coupling by separating the subject from its observers, supporting the open-closed principle. Learn the potential challenges such as managing object lifetimes, cascading notifications, reduced cohesion, and trade-offs in type-safety. This lesson helps you evaluate when to apply the Observer pattern effectively in C programs.
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Consequences
The main consequences of applying the Observer pattern are:
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Introduces loose dependencies: As the subject only knows its observers through the Observer interface, the code conforms to the open-closed principle. We may introduce any number and any types of observers that support the Observer interface by avoiding hard-coded notifications. New behavior, in the form of new types of observers, is added without modifying existing code. The loose dependencies provide a way to communicate between layers in a sub-system. Design Patterns recognizes this potential: “Because Subject and Observer aren’t tightly coupled, they can belong to different layers of abstraction in a system. A lower-level ...