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

406 Conclusions and Future Work
– integrates analysis and system design with the goal of minimising iterations
in the system development process;
– uses appropriate graphical models for easy communication with various persons
involved in a modelling process;
– enables the specification of a well-considered system structure of generic and
reusable system parts;
– produces adequate abstractions for efficient communication with various experts;
– records design decisions for the purpose of efficient future improvements.
The method gradually composes a consistent system model by simultaneous analysis
and modelling of various system properties, with emphasis on system structure
and functionality.
The method offers a framework for various modelling activities that yield distinct
views, all having a specific expressiveness. These views are partially integrated
into a unified formal and executable model.
Method elements
Concepts have been defined for the modelling of a system in terms of weaklycoupled
collaborating entities. Examples of concepts are objects, clusters, channels,
message flows, identifiers, and various forms of composites.
Process objects as well as data objects are incorporated in the method consistently
with their meaning in POOSL. Process objects are defined to model concurrent
autonomous entities connected by channels. Data objects are defined to model
data in process objects.
Classes are used to group objects and to group clusters. They abstract and generalise
properties of objects and clusters and they form the grain of behaviour
description.
Various forms of communication can be modelled by various graphical symbols.
All forms can be formalised in terms of the pair-wise synchronous message passing
primitive used in POOSL.
Channels are used for passing messages between process objects. They enable
static structuring of a system.
Boundaries are mapped on clusters. They support the modelling of various system
module properties such as internal concurrency, implementation technology and
physical distribution.
Classical object modelling, with the use of generally accepted symbols, is incorporated
in the method.