Applied Design Patterns with Java

Creational :: Prototype (117) {C ch 8}

Applicability

Use the Prototype pattern when a system should be independent of how its products are created, composed, and represented; and

• when the classes to instantiate are specified at run-time, i.e. by dynamic loading; or
• to avoid building a class hierarchy of factories that parallels the class hierarchy of products; or
• when instances of a class can have one of only a few different combinations of state. It may be easier to install a corresponding number of prototypes and clone them rather than instantiating the class manually, each time with the appropriate state.

Structure

Participants

Prototype (Graphic) - declares an interface for cloning itself.

ConcretePrototype (Staff, WholeNote, HalfNote) - implements an operation for cloning itself.

Client (GraphicTool) - creates a new object by asking a prototype to clone itself.

Catalog Creational Prev Next