Gets the Henderson-Sellers lack of cohesion metric.
The aim of this metric is to try to determine whether a class represents one abstraction (good) or multiple abstractions (bad). If a class represents multiple abstractions, it should be split up into multiple classes.
In the Henderson-Sellers method, this is measured as follows:
M = set of methods in class
F = set of fields in class
r(f) = number of methods that access field f
<r> = mean of r(f) over f in F
The lack of cohesion is then given by
(<r> - |M|) / (1 - |M|)
We follow the Eclipse metrics plugin by restricting
M to methods
that access some field in the same class, and restrict
fields that are read by methods in the same class.
High values of this metric indicate a lack of cohesion.