What is a key characteristic of the Mediator pattern?

A key characteristic of the Mediator pattern is that it provides a centralized communication point between components. This pattern serves to reduce the dependencies between communicating objects, thereby promoting loose coupling. Instead of each component needing to reference and understand each other directly, they communicate through a mediator, which transforms a complex web of interactions into a simpler and more manageable system.

By centralizing communication, the Mediator pattern also facilitates easier maintenance and changes to the system. If a component needs to change or if new components are added, the modifications often only need to be made in the mediator rather than in every individual component, enhancing the overall maintainability of the architecture. This is particularly beneficial in larger systems where direct communication could lead to a significant increase in complexity and reduce code readability.

In contrast, the other options focus on different architectural concepts. Enhancing system throughput through horizontal scaling pertains to load balancing and distribution strategies rather than communication management. Allowing direct communication between objects contradicts the loose coupling and mediation benefit, while promoting the use of global variables introduces tight coupling and can lead to challenges in state management and debugging, which the Mediator pattern aims to avoid.