Rules Engines

Rules Engine can be defined as a framework that is used to manage and automate business rules. It is very useful to have such a framework in place specially when these business rules need to be modified frequently. Often, we as software architects need to design our applications to handle such frequent change in business rules. There are several rules engines available in the market. Some of the rules engines  available are;

.Net

• Biztalk Server
• ILog Rules for .Net

Java

• Jess
• Jboss Rules
• ILog JRules

Ruby

• Ruleby
• Ruby Rools

Most of these engines, or frameworks use Dr. Charles Forgy’s Rete Algorithm. Rete is Latin for Net or network. It is a pattern matching algorithm comprising of rule compilation and rule execution. Before adopting this in your enterprise, every Architect must understand this algorithm to know the various architectural implications that it can have on the overall system like performance, scalability, etc., Also, just because you implement a rules engine, it does not mean that you can put all your business requirements and rules inside it, as some of the business rules cannot be expressed. Most often, these business rules cannot be expressed by the business users, and have to be coded by programmers.