18.5 Modeling the Model Compiler as a Domain

The subject matter covered by the model compiler domain is the subject matter of software system design. Any model compiler must provide implementations of the Executable UML formalism, no matter how indirectly. The model compiler will incorporate conceptual entities specific to the nature of the architecture: Pipes and Filters in a pipes-and-filters architecture; Classes, Operations, and Instances in an object-oriented architecture.

The model compiler domain is susceptible to being understood by modeling. It is entirely appropriate to model the model compiler using Executable UML. Or to put it another way, you can analyze your system design.

The notion of assumption and requirement pairs applies equally to the application and the model compiler domains.

• The functional requirements for the model compiler are simply to execute any domain expressed using the Executable UML formalism.

• The model compiler can be understood completely separately from the semantics of the application.

• No amount of analysis of the application will tell you that you need Classes or Pipes in the architecture. The model compiler developer chooses what goes into the model compiler.

• The primary driver of the model compiler's structure is the performance requirements of the various clients.

• Similarly, the various clients' capability requirements drive the model compiler's. The fact that the client requires a facility means that it need not be modeled in the client. (This is the idea, "Don't put design ideas into your application analysis.")

Our thanks to Leon Starr for lending us the ant and his smart-ass remark.