Software Engineering

Overview of Software Product Line Approach

The practices of software development are facing potentially dramatic change. A product line approach will remain relevant by accommodating emerging techniques, such as the capabilities of generative AI (artificial intelligence). This tutorial surveys the content of a draft book [1] that presents such an approach, built on the concept of a product family, for the systematic development of software-based products.

A product family is defined in terms of the perceived similarity (commonalities and variabilities) in behavior of an envisioned set of products. These products are seen to differ according to a set of customer-relevant deferred decisions that determine why multiple products may be needed and how each such product is to be built. Partial resolution of these decisions reduces a family to a subfamily whereas full resolution designates a particular instance of the family.

The presented approach adopts an objective of producibility—the ability to deliver needed capabilities to customers in a timely, cost-effective, and predictable manner—in building either singular evolving software products or an evolving domain with which customized software-based products targeting a coherent market can then be derived. The former option defines a software engineering formulation for building a product, expressed in the form of a notional product model. This then provides a foundation for the latter option toward building and instantiating a product family. This option is further extended to more directly address the relevance of enterprise and program management, systems and hardware engineering, and customer engagement. This approach retains the tripartite concept introduced in 1998 with the Domain-specific Engineering (DsE) methodology. DsE was a refinement and reformulation of the Synthesis methodology conceived in 1990 at the Software Productivity Consortium as the first comprehensive approach to software development based on the product family concept. DsE continues to be method-agnostic, accommodating diversity and innovation in software methods and practices, including the potential uses of generative AI.

DsE is distinguished in part by the conception of application engineering as a streamlined model-based product manufacturing process. This process entails the resolution of domain-specified deferred decisions, associated with a concrete realization of a product family, as a sufficient means for deriving, comparatively evaluating, and delivering alternative customized whole products.