A Coupling Metric for Measuring Strength of Dependency between Classes in Object-Oriented Systems

The coupling measurements of object oriented programs can be valuable information for various maintenance tasks and there exists a variety of metrics proposed by numerous researchers. Those metrics, however, cannot measure the strength of dependencies between classes, but only imply the existence of dependencies. Hence they are of limited value for assisting maintenance tasks such as refactoring and system decomposition, which requires information about the strength of dependency. In this paper, a coupling metric which can measure the strength of dependence as well as detect the existence of dependencies is proposed. Our coupling metric is evaluated based on the cost required for performing the maintenance tasks. We have applied the proposed coupling metric to an example of system decomposition in an effort to assess the potential benefits of our approach for maintenance tasks.