Model-Driven Engineering - Model-Driven and Software Product Line Engineering - page 61

A Package is composed of classes , and a Class contains
attributes .
Figure 3.2. Metamodel for class models
The relation between a model and its reference metamodel
is called conformance [BÉZ 05]. Thus, we say that a
model conforms to its metamodel, i.e. a model is written
in the language defined by its metamodel. The relation of
conformance is a mapping between the data of the model type
and the model instance. There is, first, a notion of structural
conformance that intuitively means that each element in
the model is a valid instance of its type in the metamodel.
This is true for objects, associations, inheritance, and other
links. Since the metamodel can also express constraints, a
model must also satisfy the cardinality, or other first-order
sentences expressed by these constraints. These notions are
not usually well understood by users;however,recent work has
successfully defined them. In [EGE 09], the authors propose
formal definitions for the notions of structural conformance
and semantic conformance in order-sorted logic. Furthermore
these semantics can be automatically checked by OCL tools.
According to our model and metamodel example, Figure 3.1
presents a class model that conforms to the metamodel for
class models in Figure 3.2. The mappings between abstract
and concrete syntax can be seen in the stereotypes presented
in Figure 3.1,where boxes have the stereotype that correspond
to metaconcepts.
Another metamodel example, in the context of this topic,
is Czarnecki et al.'s metamodel, which is the reference