Specifying Reusable Aspects

Aspect oriented (AO) programming enables designers and developers to manage, in a more modular fashion, implementations of crosscutting concerns (CCCs) that might be scattered or tangled if AO techniques were not utilized. Our interest in this paper is on considering techniques for specifying precise properties of aspects. In particular, we are interested in specifying reusable aspects; i.e., aspects that correspond to CCCs that occur in many systems and that can be encoded as abstract aspects that can then be reused in various systems where the particular CCC is applicable. Although there has been much work on issues related to reasoning about aspects and the behaviors of AO systems, specifying reusable abstract aspects seems to have received little attention. We adopt the following approach to specifying reusable aspects and how they are specialized for use in particular systems. We specify a reusable aspects in terms of a contract; the contract will be written in terms of abstraction concepts that will correspond to portions that are left abstract in the reusable aspect. This contract will be specialized by a subcontract corresponding to the subaspect that defines how the abstract aspect is specialized for use in a given system. Whileaspect is specialized for use in a given system. While the aspect contract is applicable to all systems built using the reusable aspect, the contract plus the subcontract define the behavior corresponding to the given system. We illustrate the approach by applying it to a simple example.