Summary of Counting Rules

In this section we will summarize the set of counting rules that have been used for the calculation of the visibility component of a class.

• For a simple class without any inheritance, the set of implicit parameters is the set of all the private, public and protected data attributes in the class. The set of possible objects that can change state is limited to the set that is visible to the methods.

• For a class that inherits from another class, the set of implicit parameters is the set of all the data attributes that are defined in the class plus the set of implicit parameters from the base class except for any attributes that are private to the base class.

  The same counting rules are used while calculating the set of implicit parameters for a class that multiply inherits from different classes.

• Constant objects and methods are not considered in the complexity calculations. The metric is designed to estimate the set of objects that have the potential to change states.

• The Visibility Component of a method does not change as it is inherited into subclasses. Even though new attributes may be introduced, the method does not contain code to access these attributes and cannot modify them. Hence, the method treats these new attributes as constant objects.

• The Visibility Component will change monotonically as the method is redefined in subclasses. The signature of the method cannot be changed. Thus the only change to the computation of the metric is in the number of attributes that are implicit to the method. Since the metric calculationis solely based on the signature, changes in the implementation of the method do not influence the value. The output/input ratio will not change, but the testability will increase as the constant multiplier changes.