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.
