3.5 Shared component scoping

The final decision dimension that we discuss in this paper is the scoping of the shared component. Of the features required by the products that use the shared component, the component can implement only the most common ones, the subset used by some or more products or all features, including those required by only one product.

3.5.1 Only common features

The starting point for most shared components is to implement only those features that are common for all products. The product teams have to extend the component with the features that their product needs.

Advantages. Assuming the common features represent a substantial subset of the features, this approach provides an efficient way to achieve early successes in the product family adoption.

Disadvantages. One concern with this approach is the often complex interface between the shared component and the product specific functionality that has to be developed on top of it. In addition, all product teams have to maintain staff with knowledge of this interface, and often the component internals, resulting in inefficient knowledge management.

3.5.2 Complete component with plug-in capability

Over time, a shared component evolves by incorporating more and more features until the point is reached where only features required by only one or two products need to be added to the component. For this, the component provides a plug-in interface.

Advantages. This model resolves, to a large extent, the issues identified for the previous model concerning the complex interface and the inefficient knowledge management.

Disadvantages. The main concern often is the integration of the component in the product. Depending on the complexity of the interaction between the component and the remaining product, the integration may be a substantial challenge.