Specification of Reactive Hardware/Software Systems - Electronic ...

6.6 Dynamic Behaviour 201
selection of the appropriate communication primitives helps us constantly in refining all
these aspects of behaviour. When we discover, for instance, an object that we can
use at various places we can design it as reusable as possible. This depends on the
message interface and the forms of communication that we use. A generic object may
offer its services without knowing beforehand, who the client will be. So the various
objects and communications are designed according to the needs we discover during
modelling. There are a lot of styles depending on grades of autonomy, independence and
reusability. These considerations show again why we do not believe in class-oriented
modelling approaches for design of complex reactive systems.
6.5.3.1 Summary
In this section we described how the concept of scenarios is used to conquer complexity
and to integrate a multidisciplinary approach into our method. This is a powerful
approach that extends the interpretations incorporated in other methods. The use of
scenarios can decrease system development time. A considered set of scenarios offers
adequate abstractions that highly improve the efficiency of the communication with
various experts.
6.6 Dynamic Behaviour
6.6.1 Introduction
Collaborating process objects can perform very complex behaviour, based on complex
communication patterns, dynamic links and parallel operations. Communications can
have various forms such as synchronous, asynchronous, and continuous. Behaviour can
be finite in time, aborted or interrupted. Data objects can be created dynamically, and
they are linked dynamically. In this section we describe the definition of the behaviour
of data classes, object classes, cluster classes and systems.
Objects and clusters collaborate via static channel structures and together form a system.
Data objects perform their tasks in a dynamically created structure, and may travel
between processes as travelling objects. There is a wide variety of styles of behaviour
description. Which style is appropriate depends on the sort of collaboration and the
requirements imposed by structures such as a distribution structure. In this section we:
assemble concepts already described;
introduce a more detailed meaning of concepts, such as state and method;
describe the available statements for behaviour description;
present the specific conceptual choices that enable behaviour description of complex
reactive hardware/software systems.
We start with an overview of related aspects in various methods before we describe our
approach in detail.