OLSEN: an object model for the real time systems design

When speaking about the object model, we start by enumerating its main features. However the use of the object model to design a system, does not take into account all of these features because objects are especially designed according to an environment and are generally not reusable in other ones. This is because the temporal behaviour and the communication between objects in a given environment are particular to this environment and not often adaptable to other situations. To solve this problem, we think that the object should be presented in three dimensions. The first dimension represents the structure of the object which is a set of private attributes, the second dimension is the behaviour of the object which is represented by a set of operations applied on the structure of the object. The third dimension (environmental or temporal dimension) represents the behaviour of the object according to an environment and especially the communications between the object itself and the other objects of the system. This paper presents an object model defined according to the three dimensional point of view. The environmental dimension corresponds to a part, called scenario, which puts the object into a given system or environment. This part allows us to define an object independently of any environment and to adapt it to a given system by defining its scenario according to this system. However, the scenario part is not reusable but the structure and the behaviour of the object corresponding to the first two dimensions are completely reusable.