Data Driven Rules Engine - Drools

Question

I have been evaluating Drools as a Rules Engine for use in our Business Web Application.

My use case is a Order Management Application.
And the rules are of

Answer 1

• There is no meaningful UI that i can offer to the end users to modify the rules.

Out of the box, Guvnor provides web based decision tables (and Excel if you prefer), as you say you would like to provide. It provides guided editors for more complex rules, but your rules would appear to be very simple.

• Guvnor UI or any Editor to modify drl files is just not acceptable from end user point of view

As mentioned, Guvnor supports decision tables. If you don't like the layout of the Guvnor web application, then you can just embed the Guvnor editors into your own web application.

• Most of these Rules will operate on often huge data available in db

The size of your database is irrelevant to the use of Guvnor. Guvnor is for editing rules, not runtime evaluation. Drools Expert is the runtime rules engine. It's fast. It can deal with very large volumes of data and very large volumes of rules. All you need to do is write database queries to get relevant chunks of that data into the rules engine at runtime. You need to do that, whatever solution you try to implement.

On a side-note, if what you're really after is an explanation of when rules engines are good (and bad) solutions to a problem, then I would recommend reading the Why use a Rule engine? section of the Drools Expert manual.