thesis - Faculty of Information and Communication Technologies ...

Chapter 4. Measuring Evolving Software
Release History
Name: String
Implemented
Interfaces
1 .. *
Version
RSN: int
Release Date: Date
1 .. *
1
Class Metric
Name: String
Package: String
Metric Data: Set
is Interface: boolean
0 .. *
0 .. *
Super Class
Depends On
Figure 4.1: UML Class diagram of evolution history model.
4.3 Software Evolution History Model
Any non-trivial object-oriented software system will generally contain
many hundreds of classes, and in order to understand the evolution of
these systems, there is a need to manage and process this potentially
large pool of data. In our study, we model the entire evolution history
of an individual project using three key elements: Release History,
Version and Class Metric. Figure 4.1 shows the relationship between
these three entities and the core data that they capture in our
model.
Release History captures the entire evolution history of a single software
system, and it holds the set of versions ordered by Release Sequence
Number (RSN). The RSN is assigned incrementally for each version
based on the release date and serves as a pseudo-time measure
[58, 174]. Every Version consists of a set of Class Metric entities
which directly map to an individual compiled Java class file and store
the metric information extracted for each class. In Java, both interfaces
and classes compile into class files and hence we model it directly as
such, with a flag within the class metric entity that determines its actual
type.
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