On the Role of Style in Selecting Middleware and Underwear

Middleware infrastructures are becoming a pervasive part of many distributed software systems. Wileden and Kaplan argue that middleware, like underwear, should not be the center of attention but should instead be kept hidden from public view, and it should never constrain or dictate what is publicly visible. These are admirable goals, yet the architects of distributed software systems must nevertheless recognize and account for the intimate relationship between middleware and the systems that use them. In particular, it is useful to view middleware infrastructures as inducing architectural styles, in the sense that they embody structural and behavioral constraints imposed on the systems that use them. Defining these styles and identifying the important relationships between them will allow architects to exploit these styles in a way that helps them defer, as long as possible, those architectural decisions that limit middleware choices, and to develop architectures that can accommodate the widest range of middleware. Otherwise, unattractive middleware choices may creep up on an architect in an annoying way.