Adaptability of object distribution protocols using the disguises model approach

Adaptability and composition are two of the most important research areas in object-oriented systems. Whereas adaptability tries to cope with system evolution by adding/replacing components, composition tries to facilitate system building by placing together different components or pieces of software. Nevertheless, object-oriented languages do not provide enough support for the development of true adaptable and composable software because either i) the different computational aspects that appear in these systems, such as synchronization, concurrency control, distribution, coordination, basic behavior, etc., are mixed in the same component or, ii) if they are properly separated in different components, once these components are woven the resulting executable piece of software is too rigid to be adapted or reconfigured at run-time. We present the disguises model, a model mainly thought for a clear and consistent separation of the synchronization, concurrency control and distribution aspects (called disguises) from the behavioral aspect. Whereas the model allows behavioral code to be written in a standard language like Java, it provides a different language for the specification of disguises and a third language for the specification of the composition rules between the disguises and behavioral components. This composition language allows synchronization, distribution and concurrency control policies to be added, replaced or reconfigured at runtime, which is the main contribution of the proposed model.