Inversion Of Control IOC with Containers (aka Dependency injection)

Inversion Of Control is a very powerful pattern as part and/or on top of the strategy pattern for loose coupling. Not only do you separate implementation from the interface (Strategy pattern), but you also invert the control of what the implementation should be. The control is no longer part of the "using" object, but control of implementation is inverted to an extern system (mostly, object containers, initialized by a using program). The container injects the implementation dependencies into all using objects that need an implementation for their required interfaces.