Análise do impacto da aplicação de padrões de projeto na manutenibilidade de um sistema orientado a objetos

Abstract

The maintenance of software systems is an indispensable part in its life cycle, be it adaptive, corrective or perfective. For this reason, it is important to be aware of the difficulty level to modify a system. This can help outline strategies to minimize the difficulty to maintenance, increasing quality and decreasing costs. This difficulty level is called in the software industry as “Software Maintainability”. This work performs a case study to analyze and measure the impact on the maintainability of an object-oriented system through the application of design patterns on the system. For this, we used a system developed in JAVA J2EE, where the source code was modified by applying certain design patterns yielding a refactored code. After refactoring the legacy system, we applied software metrics focused on maintainability like Halstead metrics, McCabe cyclomatic complexity and MI (Maintainability Index) to the legacy system and to the new system, with the purpose of comparing the results of the metrics on a detailed analysis relating the improvements obtained to the patterns applied. The analysis of the results of the metrics applied showed evidence of improvement of the quality of the system, which was measured and checked. The results of all metrics applied to the refactored system were satisfactory in relation to the results of the same metrics applied the legacy system. It was intended to show from a case study that software design patterns can contribute effectively to improving maintainability and therefore the quality of software.