Feature Diagrams

Here we will give a brief introduction to feature diagrams to ease the understanding of Figure 2. Features characterize the relevant properties of instances of a general concept. In particular, points of variation can be described by features.

The features are represented as the nodes of a tree, with the concept being the root. Features come in several flavours:

Mandatory Features

are present in a concept instance iff their parent is present. They are shown by a filled circle at the end of the edge.

Optional Features

may be present only if their parent is present. They are shown by an empty circle at the end of the edge.

Alternative Features

are a set of features from which one is present if their parent is present. They are shown by an arc grouping their edges.

Figure 4: Different flavours of features.

For a detailed discussion of feature modeling we refer to [5].