Dn-based architecture assessment of Java Open Source software systems

Since their introduction in 1994 the Martin´s metrics became popular in assessing object-oriented software architectures. While one of the Martin metrics, normalised distance from the main sequence D_n, has been originally designed with assessing individual packages, it has also been applied to assess quality of entire software architectures. The approach itself, however, has never been studied. In this paper we take the first step to formalising the D_n-based architecture assessment of Java open source software. We present two aggregate measures: average normalised distance from the main sequence Dmacr_n, and parameter of the fitted statistical model lambda. Applying these measures to a carefully selected collection of benchmarks we obtain a set of reference values that can be used to assess quality of a system architecture. Furthermore, we show that applying the same measures to different versions of the same system provides valuable insights in system architecture evolution.