Design Patterns Category Design Patterns Index 19. Observer Intent: Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically. Also Known As: Dependents, Publish-Subscribe Applicability: When an abstraction has...
Design Patterns Category Design Patterns Index 18. Mediator Intent: Without violating encapsulation, capture and externalize an object’s internal state so that the object can be restored to this state later. Also Known As: Token Applicability: a snapshot of (some portion...
Design Patterns Category Design Patterns Index 17. Mediator Intent: Define an object that encapsulates how a set of objects interact.Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently....
Design Patterns Category Design Patterns Index 16. Iterator Intent: Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation. Also Known As: Cursor Applicability: to access an aggregate object’s contents without exposing its...
Design Patterns Category Design Patterns Index 15. Interpreter Intent: Given a language, define a represention for its grammar along with an interpreter that uses the representation to interpret sentences in the language. Applicability: the grammar is simple. efficiency is not...