Variability points and design pattern usage in architectural tactics

Architectural tactics are important building blocks of software architecture. Tactics come in many shapes and sizes, describe solutions for addressing specific quality concerns, and are prevalent across high-performance fault-tolerant systems. Once a decision is made to utilize a tactic, the developer must generate a concrete plan for realizing the tactic in the design and code. Unfortunately, the variability points found in individual tactics can make this a challenging task. To address this knowledge gap, we conducted a study to investigate how design patterns were used to implement various tactics. Data mining techniques were used to identify potential pattern instances within tactic implementations. Our manual analysis of the retrieved data identified a distinct set of variability points for each tactic, as well as corresponding design patterns used to address them. From these observations we construct tactic-level decision trees depicting variability points of a tactic and generate a reference model which provides implementation guidance.