A subtyping-based flexible service adaptation mechanism for dynamic application reconfiguration support in pervasive computing environments

Abstract

Heterogeneous nature of pervasive environments requires applications to be dynamically reconfigured according to the current context. Dynamic adaptation is one of major considerations to support application reconfiguration seamlessly and transparently. However, the existing approaches only try to bind the exactly same as or similar to the service in the previous context when a user moves to a new context. If the required service does not exist, application reconfiguration fails or users are interrupted since they have to choose appropriate service components. To overcome this, we incorporate the notion of behavioral sub-typing, a principle of substitutability, into application reconfiguration. The proposed mechanism substitutes the required service with either its sub-type or its super-type in run-time when it is not available at the target context. A request to an original operation (functionality) is transparently translated into one of three cases; substitution with its sub-type, substitution with its super-type, or coercion to its super-type functionality.