8.2 DESIGN SPACE OF ARCHITECTURAL ELEMENTS

To a certain extent, design is to find the right component of a structure [3]. Therefore, it is of vital importance to understand the variety of components so that the right component can be found and used as well as the variety of ways that components can be put together. The structure of such varieties forms a space in which particular designs are elements. In this section, we consider the variety of software architectural elements and apply the theory of design space to such elements. Here, by software architectural elements, we meant both components and connectors. We systematically present knowledge about software architectural elements as a design space. To do so, we examine various observable properties of software architectural elements.

Notice that, software design has a fundamental difference from the designs of other physical artefacts. As discussed in Chapter 3, software systems are invisible; hence the notion of observable properties for physical artefacts does not make much sense for software. However, properties of software artefacts can be divided into two types: behaviour features and static features. They are similar to the functional features and observable properties, respectively. Therefore, we will first examine the behaviour features of various software architectural elements and then discuss the static features of software architectural elements.