Middleware Support For Crosscutting Features in Distributed, Heterogeneous Systems

Some “non-” or “extra-functional” features, such as reliability, security, and tracing, defy modularization mechanisms in programming languages. This makes such features hard to design, implement, and maintain. Implementing such features within a single platform, using a single language, is hard enough. With distributed, heterogeneous (DH ) systems, these features induce complex implementations which crosscut different languages, OSs, and hardware platforms, while still needing to share data and events. Worse still, the precise requirements for such features are often locality-dependent and discovered late (e.g., security policies). The DADO approach helps program crosscutting features in standard CORBA based DH middleware software through an aspect-oriented approach. A DADO service comprises pairs of adaptlets which are explicitly modeled in IDL. Adaplets may be implemented in any language compatible with the target application, and attached to stubs and skeletons of application objects in a variety of ways. DADO supports flexible and type-checked interactions (using generated stubs and skeletons) between adaptlets and between objects and adaptlets.