Rules Engines

At work we struggle with our feelings concerning our rules engine (Jess). The promise of rules engines is that the business can make rules and the Rete algorithm will determine the correct answer every time. However, the business has never shown an interest in learning how to program new rules using Jess’ lisp like language. Additionally, QA doesn’t approve of Jess’ deterministic Rete algorithm. The fact that one acceptable and correctly written new rule can change expected behaviors for all related rules and break regression tests is a nightmare for QA. ¬†As a result, I found Martin¬†Fowler’s observations about rules engines very interesting. Continue reading