Run-Time Adaptability of Synchronization Policies in Concurrent Object Oriented Languages

Abstract

Adaptability and composability have become two of the most important research areas in concurrent object-oriented systems in recent years. Nevertheless, at the present time, COOLs do not provide enough support for the development of true adaptable and composable software because either i) the different aspects that appear in these systems, synchronization and behavior, 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. Our contention is that this last feature is very important in critical control systems where, due to unexpected environment changes, urgent and not preestablished decisions must be taken at run-time. From security and economic point of views, it is not admissible to stop the application, adapt it to the new environment and re-run it. In this context, under project PRI97C161 of Junta de Extremadura, we have developed the Disguises Model, a model mainly thought for a clear separation of synchronization and behavioral aspects. A new language for the specification of the composition rules between the synchronization and behavioral aspects is provided, allowing synchronization policies to be added, replaced or reconfigured at run-time, which is the main contribution of the proposed model.