Comparison of Six Ways to Extend the Scope of Cheddar to AADL v2 with Osate

Cheddar is a framework dedicated to the specification of real-time schedulers, and to their analysis by simulation. It is developed in Ada. Some parts of its modular architecture are generated by Platypus, a software engineering tool based on the STEP standards. Cheddar owns a dedicated specification language. It can also process AADL v1 specifications. In order to extend the scope of Cheddar to AADL v2 specifications, we introduced a translation component called Dairy. It aims at creating valid Cheddar data from AADL v2 specifications. The frontend of Dairy comes from Osate v2. Hence, the backend of Dairy must produce Cheddar data from instances of the AADL metamodel that has been implemented into Osate. Both of Cheddar and Osate are legacy systems built with different frameworks, different standards and different languages. Hence, the design of Dairy poses the problem of their integration. We postulate that an implemented metamodel should neither be rewritten nor be duplicated in order to keep unchanged its legacy equipment. Then, integration should better rely on data interoperability standards. In this paper, we illustrate this idea by investigating six different designs of Dairy to perform the integration of Cheddar and Osate. We compare them with each other according to reusability, code generation, and transformation of metamodels.