• Add new functionality dynamically to existing objects, or remove it (Decorator).
• Control access to an object (Proxy).
• Create expensive objects on demand (Proxy).
• Enable development of the interface and implementation of a component to pro-
ceed independently (Bridge).
• Match otherwise incompatible interfaces (Adapter).
• Reduce the cost of working with large numbers of very small objects (Flyweight).
• Reorganize a system with many subsystems into identifiable layers with single
entry points (Façade).
• Select or switch implementations at runtime (Bridge).
• Simplify the interface to a complex subsystem (Façade).
• Treat single objects and composite objects in the same way (Composite).
