UML PROFILE FOR SAVECCM - Research

UML
The next layer, metamodel layer – M2 is an instance of M3. The UML is
positioned at M2 layer as an instance of MOF. The M2 layer is more complex than
M3 layer, its main role is to define semantics for how elements from a user model
(layer M1) that are instances of elements from the UML layer (layer M2) get
instantiated in the runtime layer (layer M0).
The M1 layer is the layer where user models are created. Instances of models
from M1 layer are running applications at M0 layer.
Figure 4-1: OMG four – level metamodel hierarchy
The four – level metamodel is shown in Figure 4-1. As an example, a Class and
Attribute metaclasses are presented. UML metaelements Class and Attribute are
instances of Class and Attribute
meta-metaelements from MOF. City is a user
defined class (as an instance of the UML metaclass Class) with an attribute
"name" (as an instance of UML metaclass Attribute), while Zagreb is an instance
of City.
When talking about elements it is important to distinguish which layer context
the talking involves (distinguish between metamodels and models). In the following
text, the Courier New font will be used to refer to UML elements that belong to
M2 layer – UML metaclasses, and Arial font will be used when talking about
elements from M1 layer – user model elements. User model elements will be
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