Improving Cohesion Metrics for Classes By Considering Dependent Instance Variables

Cohesion refers to the degree of the relatedness of the elements in a module, and it is widely accepted that the module of higher cohesion is easier to understand, maintain, and reuse. Recently, several cohesion metrics have been proposed to measure the cohesiveness of classes in an object-oriented program. However, the existing cohesion metrics do not consider the characteristics of dependent instance variables that are commonly used in a class and, thus, do not properly reflect the cohesiveness of the class. This paper presents an approach for improving the cohesion metrics by considering the characteristics of the dependent instance variables in an object-oriented program. To demonstrate the importance of the dependent instance variables, a case study has been conducted on a class library.