A Smooth Combination of Role-based Language and Context Activation

In this paper, we propose a programming language called NextEJ. NextEJ is a smooth combination of a role-based language EpsilonJ and context activation mechanisms provided by COP languages. It supports all the features of the Epsilon model such as dynamic object-role binding and unbinding, and encapsulation of collaboration of roles as a context that can be defined as a reusable module. Furthermore, NextEJ tackles typing problem of the Epsilon model by introducing the context activation scope inspired by COP languages. The key ideas described in this paper are formalized as a small core language FEJ that is built on top of FJ. FEJ’s type system is proven to be sound.