metrics – Page 2 – Simple Oriented Architecture

Clean Code

How to identify a God Class using NDepend

Most of the static analysis tool in the .Net world report isolated code metrics. While this is useful, I would like to be able to detect coarse grained code smells. Being able to correlate several metrics to identify design disharmonies allows you to treat a problem holistically. In this blog post we’ll see how we can use NDepend to detect potential God Classes.

God Class Detection Strategy

A God Class is a class that centralizes the intelligence in the system. It is large, complex, has low cohesion and uses data from other classes. Object-Oriented Metrics in Practice, by Michele Lanza and Radu Marinescu, proposes the following detection strategy for a God Class:

(ATFD > Few) AND (WMC >= Very High) AND (TCC < One Third)

Quality

Computing the Overview Pyramid metrics with NDepend

The Overview Pyramid describes and characterizes the structure of an object oriented system by looking at three main areas: size and complexity, coupling and inheritance. This visualization technique has been defined by Radu Marinescu and Michele Lanza in their book Object-Oriented Metrics in Practice. In this blog post we’ll see how to compute all the necessary metrics by using NDepend.

The Overview Pyramid

Example Overview Pyramid — source: https://commons.wikimedia.org/wiki/File:Overview_pyramid.jpg

The purpose of the Overview Pyramid is to provide a high level overview of any object oriented system. It does this by putting in one place some of the most important measurements about a software system. The left part describes the Size and Complexity. The right part describes the System Coupling. The top part describes the inheritance usage.

Books, Quality

Book Review: Object-Oriented Metrics in Practice

I have been using static code analyzers for a while now. While these are useful, you need to spend a lot of time analyzing warnings and issues. And the problem is that, after you first run one of the static code analysis tools on a legacy project, you are overwhelmed by the number of issues. Object-Oriented Metrics in Practice, by Michele Lanza and Radu Marinescu, shows us how to use metrics effectively. It shows how to combine metrics in order to spot design flaws. This book also presents some novel visualization techniques. These are a great way to understand and visualize a complex system.

Quality

Visualizing Code Metrics with NDepend

Lines of code, cyclomatic complexity, coupling, cohesion, code coverage. You’ve probably heard about these metrics before. But do you actively track them? Should you? Visual Studio computes some of these metrics out of the box. But if you want to define a custom metric, you’re out of luck. Yet, there are a bunch of code metrics that you might find useful for your code base. More so, a composite metric might be more helpful than the sum of its parts. For example, the C.R.A.P. Metric detects complex code that is not covered by unit tests. How can you track such a metric in Visual Studio? In this article we’ll see how to visualize code metrics, add custom metrics and how to monitor trends with NDepend.

Code Metrics

NDepend computes many metrics out of the box. You can use the intellisense support to discover the standard metrics for a given code element:

But it would be hard to extract information from these metrics if all we got was a bunch of numbers. We need other techniques to help us break down the complexity of the data. Visualization techniques complement metrics, by making it easier to synthesize and digest this information.