Mediator pattern

1. Mediator pattern

2. Intent
● Define an object that encapsulates how a set of
objects interact.
● Design an intermediary to decouple many
peers.
● Promote the many-to-many relationships
between interacting peers

3. Problem
● dependencies between the potentially reusable
pieces demonstrates the "spaghetti code"
phenomenon.

4. Motivation
● By consolidating all interaction in a single class,
we can regain elegance and reusability.

5. UML

6. Examples

8. Pros & Cons
Pros:
● Decouples colleagues, which facilitates independent
variations of the colleague and mediator classes.
● Simplifies protocol by replacing many-to-many interaction
with one-to-one interaction
Cons:
● Reducing the complexity of Colleagues increases
the complexity of the Mediator itself.

9. Related patterns
● Observer: the Mediator class may be
implemented using an Observer
● Facade: is similar to a Mediator, but with one-
way communication from the Facade to its
subsystem classes..