Often the
limited capabilities of tools for creating new metamodels and modifying existing
languages also partly dictate the language selection and modi?¬?cation.
10.2.4 De?¬?ning Modeling Concepts
Having identi?¬?ed the abstraction for the speci?¬?cation work along with some suitable
models of computation, you should start mapping domain concepts to modeling
concepts. While doing so, you balance between having a dedicated modeling concept
and leaving decisions to the modeler. So the question you often need to answer is:
should this particular concept be an instance value or a type? A string entered by a
modeler or recognized by the language?
Next let??™s consider an example: howshould icons in a digital wristwatch (Chapter 9)
be handled in the language? Should it be a particular kind of instance value a modeler
enters into the model or a concept of a modeling language? The choices could be as
follows:
1. Apply a certain naming convention to identify that this model element is an
icon. The modeling concept used to specify icons is thus more general since it
can also be used to specify elements other than icons.
2. Use some built-in language extension mechanism. In UML, this could be done
by giving a stereotype <
> to the model element.
3. Have a dedicated Icon concept in the language. This Icon concept can then
have the properties and other constraints relevant just for icons.
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