Drools is a Business Logic integration Platform (BLiP). It is written in Java. It is an open source project that is backed by JBoss and Red Hat, Inc. It is licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0.html). This book will focus on version 5.0 of this platform that was released in May 2009.
Work on Drools (the rule engine) began in 2001. From its beginning, Drools underwent many changes.
Drools 1.0 started with a brute force linear search. It was then rewritten in version 2.0, which was based on the Rete algorithm. The Rete algorithm boosted Drools performance. Rules were written mainly in XML. The next version (3.0) introduced a new
.drl format. This is a specific language specially crafted ...