Mediator Vs Observer Object-Oriented Design Patterns

Question

I have been reading the Gang Of Four, in order to solve some of my problems and came across the Mediator pattern.

I had earlier use

Answer 1

These patterns are used in different situations:

The mediator pattern is used when you have two sub-systems with some dependency and one of them is due for a change, and since you might not want to change the system that depends on the other, you may want to introduce a mediator which will decouple the dependency between them. That way, when one of the sub-systems changes, all you have to do is to update the mediator.

The observer pattern is used when a class wants to allow other classes to register themselves and receive notifications upon events, e. g. ButtonListener etc.

Both of these patterns allow for lesser coupling, but are quite different.