Services and Objects: Open Issues

One of the common metaphors used in textbooks on Object-Oriented programming (OOP) is to view objects in terms of the services they provide, describing them in “service oriented” terms. This opens a number of interesting questions, moving away from the simple view of OOP as an implementation tool for Web Services. First of all: if an Object is a Service, can we also say that a Service is an Object? While the short answers seems to be negative, there are several connections between the two concepts and it is possible to exploit the large repository of methodological tools available in OOP. What are the counterparts, in terms of services, of concepts like class or instance? Is it possible to apply techniques as containment or inheritance to services? What are interfaces, properties and methods for services? In this paper we try to start building some connections, underlining the open issues and the gray areas.