Enterprise Service Bus

Chapter 3. Necessity Is the Mother of Invention

The ESB is a new architecture for integration that is flourishing in corporations around the world. To many casual observers, the ESB as a technology category seems to have come out of nowhere. In reality, though, the ESB has not just “happened.” Over time, many catalysts helped it develop and evolve, and lessons were learned from past technology approaches that extend back more than a decade.

This chapter will examine some key concepts of the ESB, including the many requirements, technology drivers, and forces in the IT climate that led to the creation of the ESB concept. All of this will be discussed in the context of the recent history and evolution of the ESB. This discussion will illustrate the point that an ESB is not merely an academic exercise; it was born out of necessity, based on real requirements arising from difficult integration problems that couldn’t be solved by any preexisting integration technology. The discussion will conclude with a study of an ESB deployment, with a manufacturer exposing inventory management and supply chain optimization functionality to its remote distributors as shared services through an ESB.

Sometimes solving a problem requires looking at previous attempts at solutions and learning from their drawbacks. Entire trends had to come about as predecessors to ESB for the IT and vendor communities to have something to point at and say, “I like that,” “I don’t like that,” or “That’s what I’ve been trying ...