| Adapter |
Allows incompatible interfaces to work together |
Reuse or make two incompatible classes work together |
Create an adapter class that implements the desired interface and wraps an instance of the incompatible class. |
| Bridge |
Separates abstraction from implementation |
Decouple abstraction and implementation |
Create abstraction and implementation hierarchies and bridge them using composition. |
| Composite |
Represents part-whole hierarchies |
Create a hierarchical structure of objects |
Define a common interface for leaf and composite objects and implement the pattern using composition. |
| Decorator |
Dynamically adds responsibilities |
Extend functionality of individual objects |
Create decorator classes that wrap objects and add behavior. |
| Facade |
Provides a simplified interface to subsystems |
Simplify complex subsystem interactions |
Create a facade class that encapsulates interactions with the subsystem. |
| Flyweight |
Shares common state among objects |
Efficiently support a large number of similar objects |
Identify intrinsic and extrinsic properties; create a factory to manage shared intrinsic properties. |
| Proxy |
Provides a surrogate or placeholder |
Control access, add functionality, or implement lazy loading |
Create a proxy class that implements the same interface as the real object and forwards requests. |
