Software quality estimation is a challenging and time-consuming activity, and
models are crucial to face the complexity of such activity on modern software
applications. In this context, software refactoring is a crucial activity
within development life-cycles where requirements and functionalities rapidly
evolve. One main challenge is that the improvement of distinctive quality
attributes may require contrasting refactoring actions on software, as for
trade-off between performance and reliability (or other non-functional
attributes). In such cases, multi-objective optimization can provide the
designer with a wider view on these trade-offs and, consequently, can lead to
identify suitable refactoring actions that take into account independent or
even competing objectives. In this paper, we present an approach that exploits
NSGA-II as the genetic algorithm to search optimal Pareto frontiers for
software refactoring while considering many objectives. We consider performance
and reliability variations of a model alternative with respect to an initial
model, the amount of performance antipatterns detected on the model
alternative, and the architectural distance, which quantifies the effort to
obtain a model alternative from the initial one. We applied our approach on two
case studies: a Train Ticket Booking Service, and CoCoME. We observed that our
approach is able to improve performance (by up to 42\%) while preserving or
even improving the reliability (by up to 32\%) of generated model alternatives.
We also observed that there exists an order of preference of refactoring
actions among model alternatives. We can state that performance antipatterns
confirmed their ability to improve performance of a subject model in the
context of many-objective optimization. In addition, the metric that we adopted
for the architectural distance seems to be suitable for estimating the
refactoring effort.Comment: Accepted for publication in Information and Software Technologies.
arXiv admin note: substantial text overlap with arXiv:2107.0612
