On the Customization of Components: A Rule-Based Approach

Realizing the quality of service (QoS) requirements for a software system continues to be an important and challenging issue in software engineering. A software system may need to be updated, or reconfigured, to provide modified QoS capabilities. These changes can occur at development time or at run-time. In component based software engineering, software systems are built by composing components. When the QoS requirements change, there is a need to reconfigure the components. Unfortunately, many components are not designed to be reconfigurable, especially in terms of QoS capabilities. It is often labor-intensive and error prone work to reconfigure the components, as developers need to manually check and modify the source code. Furthermore, the work requires experienced, senior developers, which makes it costly. The limitations motivate the development of a new rule-based, semi-automated component parameterization technique that performs code analysis to identify and adapt parameters and changes components into reconfigurable ones. Compared with a number of alternative QoS adaptation approaches, the proposed rule-based technique has advantages in terms of flexibility, extensibility and efficiency. The adapted components support the reconfiguration of potential QoS trade-offs among time, space, quality, etc. The proposed rule-based technique has been successfully applied to two substantial libraries of components. The F-measure or balanced F-score results for the validation are excellent, that is, 94 percent.