Layering

Layering

Description

In addition to the Actor containment hierarchies, Layering provides another method to hierarchically structure a software system. Layering and actor hierarchies with port to port connections can be mixed on every level of granularity.

  1. an ActorClass can define a Service Provision Point (SPP) to publish a specific service, defined by a ProtocolClass

  2. an ActorClass can define a Service Access Point (SAP) if it needs a service, defined by a ProtocolClass

  3. for a given Actor hierarchy, a LayerConnection defines which SAP will be satisfied by (connected to) which SPP

Notation

Description Graphical Notation Textual Notation
The Layer Connections in this model define which services are provided by the ServiceLayer ( digitalIO and timer)
The implementation of the services (SPPs) can be delegated to sub actors. In this case the actor ServiceLayer relays (delegates) the implementation services digitalIO and timer to sub actors
Every Actor inside the ApplicationLayer that contains an SAP with the same Protocol as timer or digitalIO will be connected to the specified SPP