3.8 The design process

Catalysis recommends the micro-process for system and component specification and design illustrated in Figure 35. One may begin either with actions or with objects, or perhaps both. In the former case one elicits the actions that the system partakes in, finding out also who (or what) the actors are. Writing post-conditions on the actions then teases out the vocabulary that the type model must clarify. Now the techniques of snapshot, sequence and state diagrams are used to clarify and refine the model, leading to new and additional actions. And so on round the loop, introducing more detail and eventually moving from a specification to a design and implementation.


Figure 35 The Catalysis specification and design micro-process.

The important design principles that should be applied during the process are as follows.