Mediator

Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently.

Applicability

• Complex interaction exists, and you don't what to bury the interaction in the objects
• Reuse is difficult due to communciation paths
• Distributed behavior should be customizable without a lot of subclassing

Consequences

• Limits subclassing
• Decouples colleagues
• Simplifies object protocols
• Abstracts how objects cooperate
• Centralizes control