Design Patterns in Java™, Second Edition

10 Mediator

ORDINARY OBJECT-ORIENTED development distributes responsibility as far as it will go, with each object doing its own work independently. For example, the OBSERVER pattern supports this distribution by minimizing the responsibility of an object that other objects find interesting. The SINGLETON pattern resists the distribution of responsibility and lets you centralize responsibility in particular objects that clients locate and reuse. Like SINGLETON, the MEDIATOR pattern centralizes responsibility, but for a particular set of objects rather than for all the clients in a system.

When the interactions between the objects gravitate toward the complex condition whereby every object in a group is aware of every other object in that group, ...