Drools is a business rules management system that provides a business rules engine. It supports the JSR-94 standard. Mule has a Drools component to execute business rules in applications. The document demonstrates creating a simple Mule application that uses business rules defined in a .drl file through the Drools component. The application generates a random weight variable and checks the rules to set the destination to either WAREHOUSE_A or WAREHOUSE_B depending on if the weight is above or below 50.

1. By Anirban Sen Chowdhary

2. Drools : Drools is a Business Rules Management System (BRMS) solution. It provides a core
Business Rules Engine (BRE).
Drools supports the JSR-94 standard for its business rule engine and enterprise framework
for the construction, maintenance, and enforcement of business policies in an organization,
application, or service.

4. Mule have Drools component to execute business rules in it’s application

5. Now, let us create a simple application in our Anypoint studio. This
application we will be deploying and running in our Mule Standalone Server
and will be using Business rules in our Mule application using Drools

6. We need to keep a .drl files in our application where all the business
rules will be defined .. In our case all the business rules are in this
routingRules.drl file:-

7. Rules in the routingRules.drl are defined as follows:-
You can see the rules that if weight variable value is less than or equal to 50 then
WAREHOUSE_B will be as printed as destination or else WAREHOUSE_A will be printed

8. You can see Mule code that the variable weight is generated randomly and the value of
the weight is been checked by the Drools component which is referring
routingRules.drl where all the rules are set :-

9. You can see the value in weight variable is generated randomly and the
destination value is set to WAREHOUSE_B as defined in .drl file
Now we test our application by hitting http://localhost:8082/example
and we will get the following:-

10. You can see the value in weight variable is again generated randomly
and the destination value is set to WAREHOUSE_A as the weight value
is greater than 50 and the rules are defined in .drl file
Now we hit the url http://localhost:8082/example again and we will
get the following:-

11. In my next slide I will bring some other techniques in Mule
implementation .
Hope you have enjoyed this simpler version.
Keep sharing your knowledge and let our Mule community grow 