12.5 Layering
12.5.1 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.
- an ActorClass can define a Service Provision Point (SPP) to publish a specific service, defined
by a ProtocolClass
- an ActorClass can define a Service Access Point (SAP) if it needs a service, defined by a
ProtocolClass
- for a given Actor hierarchy, a LayerConnection defines which SAP will be satisfied by
(connected to) which SPP
12.5.2 Notation
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| Description | Graphical Notation | Textual Notation |
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The Layer
Connections in this
model define which
services are
provided by the
ServiceLayer
(digitalIO and
timer)
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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
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Every Actor inside
the
ApplicationLayer
that contains an
SAP with the same
Protocol as timer
or digitalIO will be
connected to the
specified SPP
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_ServiceLayer_ (_digitalIO_ and _timer_)</td> actor _ServiceLayer_ relays (delegates) the
implementation services _digitalIO_ and _timer_ to sub actors</td> _timer_ or _digitalIO_ will be
connected to the specified SPP</td>