Part Four continues our tour of the Architecture Business Cycle. Parts One, Two, and Three Three took us from the architect to a reviewed architecture. Part Four focuses on the construction of multiple systems from that architecture, discussing, and giving examples of system product lines. It does this from five perspectives: that of the technology underlying a product line, that of a single company that built a product line of naval vessel fire-control systems, that of an industry-wide architecture, that of a single company producing products based on the industry-wide architecture, and that of an organization building systems from commercial components.
Software product lines have the potential to re-use everything from requirements to test plans to personnel. The key to this re-use is architecture. Chapter 14 focuses on defining and developing an architecture for a product line. We deal with organizational issues here since, as you should be well aware of by now, there is a strong relationship between architecture and organizations.
Chapter 15 is our first case study. It is the story of a Swedish company, CelsiusTech, that constructed a product line of fire-control systems for naval vessels. We discuss the architecture here, but we also discuss in some detail how its organizational structure and culture changed as a result of adopting a product line.
CelsiusTech was a single organization building an architecture for multiple products. However, industries also have supporting architectures. For example, Java 2 Enterprise Edition/Enterprise JavaBeans (J2EE/EJB), an architectural specification designed for Web-based information systems, acts as a base architecture for products developed by many companies. Chapter 16 discusses J2EE/EJB's architectural decisions and the tradeoffs that are possible within it.
One of the companies building products based on J2EE/EJB is Inmedius, which produces solutions for frontline workers, such as maintenance technicians, who cannot sit in front of a desktop and rarely use a laptop but instead rely on a variety of mobile platforms. How Inmedius architected a solution based on wireless technology and wearable and handheld computers is the subject of Chapter 17.
Chapter 18 discusses constructing a single system when given an architecture and a collection of commercial components. We will see if there was anything left to design and build.
Finally, we end by engaging in our favorite pastime?predicting the future of software architecture. Chapter 19 presents our guesses (and they are no more than that) as to what might be in store.