Design PatternsStructural patterns giải quyết cách compose class và object thành larger structures. Chọn theo use case:
- Adapter: tích hợp incompatible interface (thường là third-party lib)
- Bridge: thiết kế mới cần tách abstraction-implementation để scale độc lập
- Composite: dữ liệu có dạng tree, cần treat leaf/branch đồng nhất
- Decorator: thêm behavior tại runtime mà không sửa class gốc
- Facade: đơn giản hóa subsystem phức tạp cho client
- Proxy: control access hoặc add cross-cutting concern (logging, caching, auth)
- Flyweight: memory optimization critical với nhiều objects tương đồng
Nhiều pattern Structural có thể kết hợp — Facade có thể dùng bên trong các Proxy; Decorator và Composite hay đi cùng nhau trong UI tree.
Structural patterns address how to compose classes and objects into larger structures.
- Choose by use case: use Adapter when integrating an incompatible interface (typically a third-party library); use Bridge when a new design needs to separate abstraction from implementation so they can scale independently; use Composite when data forms a tree and you need to treat leaves and branches uniformly; use Decorator when you need to add behavior at runtime without modifying the original class; use Facade when a complex subsystem needs a simpler interface for clients; use Proxy when you need access control or want to add a cross-cutting concern (logging, caching, auth) without touching the original; use Flyweight when memory optimization is critical and there are large numbers of similar objects.
- Rule of thumb: many Structural patterns can be combined — a Facade can be backed by Proxies; Decorator and Composite often appear together in UI trees.