Towards safe and flexible object adaptation

Abstract

In this paper, a programming language NextEJ is proposed. NextEJ is based on Epsilon model, which realizes object adaptation to contexts. The novelty of Epsilon model is its ability to make objects be able to freely enter or leave contexts dynamically and belong to multiple contexts at a time. However, such kind of flexibility also easily brings type-unsafety. NextEJ tackles this problem by introducing a new feature called context activation scope. Inside a context activation scope, it is assured that an object is always bound with the role activated so that no method-notunderstood errors occur at run-time. Furthermore, context activation scope can be nested so that multiple contexts can be activated at a time. A role instance has a pre-defined field thisContext which refers to its enclosing context instance. In the case of multiple context activations, the reference of thisContext is interpreted as a composite context whose behavior is determined by the order of activations.

Enabling View-based Programming with SCROLL

“…Compartments can contain other compartments. [24,27,29]. This nesting is proposed to further structure compartments into smaller sub-compartments [24,29] and, e.g.…”

A Metamodel Family for Role-Based Modeling and Programming Languages

“…In addition to the previous properties, three approaches allow compartments to contain other compartments [37,41,42]. This nesting is proposed to further structure compartments into smaller sub-compartments [37,42] and, thus, enable the representation of a university containing academic departments which in turn contain faculties.…”

“…This nesting is proposed to further structure compartments into smaller sub-compartments [37,42] and, thus, enable the representation of a university containing academic departments which in turn contain faculties.…”

“…Compartments have their own identity. This feature is acknowledged by all approaches who treat compartments as first-class entities of the instance level [60,37,46,50,42,34]. Thus, this feature is a prerequisite for the existence of compartments at runtime.…”

“…Nonetheless, the project has been abandoned [59]. A more recent approach towards context oriented programming is NextEJ [42] as the successor of EpsilonJ [54]. It provides Contexts as first class citizens which do not only group roles but also represent an activation scope at runtime.…”