Evolution - Programming GPS and OpenStreetMap Applications with Java - page 223

Figure14.6. Any RO hierarchy can be modeled with a number of roaf.ros
packages.
The most used objects tested in different scenarios will gradually gain
robustness, quality, and become more realistic and (each consecutive ver-
sion) learn to survive many scenarios and become an certified member of
a RO hierarchy (see Figure 14.6).
RealObject
The RO is the root of the hierarchy (or hierarchies) and intentionally de-
signed to be abstract . The actual values for mass and shape have to be
provided with the extension and instantiation to a real thing. Technically,
the RO provides the basic mechanisms for a client-server handshake to
identify and authorize the client for the server application.
In the long run, it might be necessary to provide mechanisms to provide
values interactively, when signing up on a less known server application, for
example. Different scenarios can apply different rules (and laws) to address
dedicated attributes (and methods) of the actors. Isolated ROApps (i.e.,
those not certied for the ROAF) could \switch on" gravity to observe the
objects falling in the gravity field; the mass attraction on Earth should
vary from a moon scenario.