Architectural Smell Definitions and Formalizations

In this section, we provide definitions of basic software architectural concepts and use them to define architectural smells. Our definitions are not intended to be complete; they are restricted to those architectural concepts that will be useful for identifying smells. We also provide shorthand predicates in Figure 1 that we use to help us define architectural smells. A software system’s architecture is a graph G whose vertices are “bricks” (software components and connectors) and whose topology represents the interconnections among those bricks. In order to represent and detect architectural smells, we model a system’s architecture as a tuple comprising G, the nonempty set of “words” W that are used to “describe” (i.e., implement) the system modeled by the architecture, and the nonempty set of “topics” T addressed by the system; each topic is defined as a probability distribution over the system’s words. By examining the words that have the highest probabilities in a topic, the meaning of that topic can be discerned. In this way, a topic can serve as a representation of a concern addressed by a software system. In other words, the set of topics T is a representation of the system’s concerns.