In an object-oriented target language, these data structures will be instances of
classes de?¬?ned by the domain framework. The class structure will mirror the structure
of the corresponding type in the modeling language. Properties will be mapped
into member variables of the class, and some of the relationships and similar links to
other model elements may also become member variables. Relationship types
themselves may sometimes map to their own class, with the main member variables
holding the objects they connect, and extra variables for the properties of the relationship
and roles.
Whatever the type of the target language, such data structures will have associated
behavior. Perhaps more commonly than in traditional frameworks, an important part
of that behavior will be the accessors and constructors. The model contains data in a
format that is easy for a human to work with, but the code that will use these data
structures will want to access it in a machine-friendly format. That transformation can
be accomplished either by the generator, the constructor and/or setter accessor, or the
getter accessor.
In all but the simplest cases, the generator would be a poor place to carry out
this transformation: it is better to keep the code that produces the internal format in
the same place where that format is de?¬?ned.
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