The ROOM model defines classes for Data, Protocols, Actors, SubSystems and LogicalSystems. Thereby the three latter form a hierarchy. The @LogicalSystem@ is the top level element of the structure. It contains references to SubSystemClass elements. The SubSystemClass in turn contain references to ActorClass elements which again contain (recursively) references to ActorClass elements. The complete structural hierarchy implies a tree which has the LogicalSystem as root and where each reference stands for a new node with possibly further branches.
Let’s consider a simple example. It doesn’t implement any meaningful and completely omits behavioral and other aspects.
When a LogicalSystem is instantiated then recursively all of the contained referenced elements are instantiated as instances of the corresponding class. Thus the instance tree of above example looks like this (the third line in the white boxes shows some mapping information, s.b.):
