Preface – Jess in Action: Rule-Based Systems in Java


In 1994, I was working in the Scientific Computing department at Sandia National Laboratories in Livermore, California. We had an impressive (for the time) array of heterogeneous computing equipment: workstations from Silicon Graphics and Sun Microsystems, Intel PCs running Linux, Macintoshes galore. I was writing software agents that managed dynamically distributed computations across this network. Agents were running on each machine, and they used a sort of “post and bid” method to decide which machines would run which piece of a computation, based on machine capabilities and load balancing. The agents were fairly intelligent in their decision-making capabilities, and the plans they developed were sometimes surprising. Their “brains” were rule engines—software systems that used rules to derive conclusions from premises.

That project led to others, and soon I developed an interest in mobile agents—software entities that can travel from node to node in a computer network, maintaining their state as they go. Thus was born the idea for a rule engine whose state could be packaged up, sent across a wire, and reconstituted. The newly released Java language seemed to be a perfect vehicle for this rule engine—and such was the origin of Jess™, the rule engine for the Java Platform.[1]

1 Jess is a registered trademark of the Sandia Corporation.

Jess is a general-purpose rule engine, developed at Sandia National Laboratories. Written in the Java programming language, Jess offers easy integration with other Java-based software. Jess is free for academic and government use, and it can be licensed for commercial use. You can download a fully functional Home Edition of Jess free of charge if you own a copy of this book (see chapter 3 for download instructions). You can use the Jess Home Edition for noncommercial purposes.

Jess has evolved quite a bit since its original introduction in 1997, largely in response to feedback from a global user community. I’ve enjoyed working on Jess the whole time, and look forward to its continuing evolution in the future.