Information Technology Reference
In-Depth Information
MappedElement
(
∃ incomingEdge.SequenceEdge
∃outgoingEdge.SequenceEdge
)
Required
(15)
incomingEdge, outgoingEdge isRequired
(16)
Container Element.
BPMN models facilitate grouping and decomposition of
activities. Axiom 17 describes that container elements such as groups and sub-
processes are supposed to be required by their elements. Groups in a BPMN
model use the property
activities
to define which activities are members of this
group, while subprocesses use the properties
vertices
and
sequenceEdges
.These
properties are defined as subproperties of
isRequired
in order to have a connec-
tion to the element's counterparts (Axiom 18).
MappedElement
(
∃ activites.Element ∃vertices.Element
∃sequenceEdges.Element
)
Required
(17)
activities, vertices, sequenceEdges isRequired
(18)
Conditional Flow.
Activities with outgoing conditional sequence edges impose
the existence of at least one unconditional outgoing sequence edge. This con-
straint might be violated in the case an unconditional sequence edge is mapped
and could be possibly removed in a certain configuration. For instance, consider
the mapping of the optional feature
MultipleW ishList
to the conditional out-
going edges of the activity
RequestW ishList
in Fig. 1. In this case, a feature
configuration could result in a process model without any outgoing uncondi-
tional edge. In order to avoid this, we describe in Axiom 19 that a mapped
unconditional edge which is the only outgoing edge is required.
MappedElement UnConditionalEdge ∃source.
(
Activity
∃
≤
1
outgoingEdge.UnConditionalEdge
)
Required
(19)
source ◦ outgoingEdge isRequired
(20)
Opening Gateway.
An opening gateway is used to express the divergence of a
control flow. While the number of outgoing branches is arbitrary in general, it
is required that there are at least two outgoing sequence edges. Otherwise the
gateway does not represent any divergence. Axiom 21 defines a mapped sequence
edge that is one of at most two outgoing edges as a required element. Axiom 22
defines the property composition of
source
and
outgoingEdge
as subproperty of
isRequired
in order to find the counterparts.
MappedElement SequenceEdge ∃source.
(
OpeningGateway
∃
≤
2
outgoingEdge.SequenceEdge
)
Required
(21)
source ◦ outgoingEdge isRequired
(22)
Closing Gateway.
The convergence of a control flow in a process is described
by closing gateways. Like for opening gateways, a closing gateway needs at least
two incoming sequence edges. Axioms 23 and 24 are similar to the previous
Axioms just for closing gateway.
