Chapter 22. Layered System


Structure the use-case model so that each use case is defined within one layer, and use relationships between the use cases in different layers to allow use-case instances to span multiple layers.

Characteristics: Common in mid-size and large systems. Advanced solution.

Keywords: Accessing lower layers, application-specific functionality, dependency direction, directed dependency, domain-specific functionality, level of abstraction.


In each of the Layered System patterns, there are two packages modeling two layers, and a package import relationship from the package representing the upper layer to the package representing the lower layer. The relationship implies that the (public) contents of the lower-layer ...

Get Use Cases: Patterns and Blueprints now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.