Preface to the First Edition

I’ve always felt that implementing a software system is much harder than it needs to be. It is difficult to map requirements to the implementation and then trace the implementation back to the requirements. Although many approaches—such as object-oriented programming, component-oriented programming, and design patterns—help to some extent, none of them satisfactorily addresses the system-level requirements, often referred to as crosscutting concerns, that must be included in multiple modules.

I came across AspectJ version 0.3 in 1998 while looking for better ways to architect a Java-based system. AspectJ was an implementation of aspect-oriented programming (AOP), a new methodology that specifically targeted the management of crosscutting concerns. Even though AspectJ was in its infancy, I became fascinated by its potential. The struggle to keep up with all the new advances in the Java and XML world, along with other priorities in my life, prevented me from pursuing it further. Still, exploring AspectJ was always on my to-do list, and I started looking at it again when it was in version 0.8. By then, AspectJ had evolved into a much more powerful language. I started using AspectJ and found that the more I used it, the more I fell in love with it. Today, the current version of AspectJ (1.1)—which this book is based on—has morphed into a mature, robust language.