Façade (2)
		• Motivation – Structuring a system into subsystems reduces complexity – Want to reduce communications and dependencies between subsystems • Applicability – Want to provide a simple interface to a complex subsystem – There are many dependencies between clients and implementation classes in a subsystem.  Want to decouple the subsystem from clients and other subsystems – Want to layer subsystems – Can use a façade to define entry point to each subsystem level