refactoringresharperndependautomated-refactoringcode-metrics

Is it possible to use NDepend to find class partitioning in an OOP language?

Fort first let me better explain the context and the problem.

Context

We have a big class with dozen of methods; it violates many Software Engineering principles and this is clearly visible through a code metrics measure tool. See poor cohesion, too many method, and so on.

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The problem When we try to split the class into smaller classes the problem arise with the instance methods. They need to access one or more field / property from the class and it may be useful to put all together the methods which access a specific field / property. The issue is clearly visible when trying to move a bunch of methods to a new class with Resharper → Refactor → Extract Class.enter image description here

Is it possible to partition the methods and fields which are connected together (have an high cohesion to use code metric terminology)?

Solution

  • Certainly we can do something interesting here, but this requires a partition algorithm and I am not sure which one to choose.

    The query could look like:

    // Replace "NHibernate.Cfg.Configuration" with your "Namespace.TypeName"
let type = Application.Types.WithFullName("NHibernate.Cfg.Configuration").Single()
let dicoFields  =  type.Fields
   .ToDictionary(f => f, f => f.MethodsUsingMe.Where(m => m.ParentType == f.ParentType))
let dicoMethods = type.Methods
   .ToDictionary(m => m, m => m.FieldsUsed.Where(f => f.ParentType == m.ParentType))

// The partition algorithm on both dicos here

from pair in dicoFields 
orderby   pair.Value.Count() descending
select new { pair.Key, pair.Value } 

//from pair in dicoMethods 
//orderby   pair.Value.Count() descending
//select new { pair.Key, pair.Value}

    Does this help moving forward?

    NDepend field method partition algorithm