Dependency cycles in software systems have very negative impact on characteristics like testability, understandability and reuse (as explained here). Cycles with only a few nodes (say 5 to 10) might be resolveable quite simply by manually analyzing them. For bigger cycles it is helpful to have an automated analysis at hand based on an algorithm solving the minimum feedback arc set problem. A feedback arc set of a directed graph is a subset of its arcs that upon removal would transform a cyclic into an acyclic directed graph. Such an algorithm combined with user input about the domain (i.e. which dependencies are absolutely necessary and which absolutely violate design decisions) is able to deliver excellent results. (more…)
Over time software systems tend to develop several negative symptoms: simple changes require a surprisingly big effort to be implemented, changes cause the system to break in unrelated areas, reuse of code in other systems is simply not feasible, the code is hard to read and understand even for the directly involved programmers. One of the main reasons of facing these symptoms is an unintended increase of the overall system coupling.
Except for very small systems the manual control of the overall coupling is a tedious task – a tool-based approach is needed. Sonargraph-Explorer is such a tool and among other things it helps the developer to assess and control coupling and work against its accidental increase. It is the first product built upon the new Sonargraph Next Generation platform supporting Java, C# and C/C++. It offers different visualizations of dependency structures and a powerful scripting engine based on Groovy which allows extending the built-in analysis capabilities.
The following content introduces the needed definitions and terms related to component coupling (one way to express the overall system coupling). It explains how to use Sonargraph Explorer to visualize the corresponding dependencies and determine components contributing significantly to the overall system coupling with a custom script automatically. (more…)