One of the major issues with object‑based techniques is
how to capture the logical structure of the system. Real‑time systems
have a static nature such that their underlying instance structure
exists once the system starts because we do not want to dynamically
allocate and free memory during run time. Therefore, the static structure
is an instance structure rather than a class structure, the primary
view in most non-real-time object‑oriented systems. In IBM® Rational® Rhapsody®,
therefore, the instance (or object) is the prime concept.
The structural model consists of the objects in
the system and the static relationships that exist between them. Groups
of objects can be partitioned into packages or subsystems. Object
model diagrams define the structural model. This section describes
the code generated from object model diagrams.