Drools Rule Management System with Spring Boot

Drools rule management system with spring boot Social media caption Say goodbye to manual rule management and hello to efficiency with Drools and Spring Boot.

Check out this latest blog post to learn more. #RuleManagement #BusinessAutomation #Drools #SpringBoot

What is Drools?

Drools is an open-source Business Rules Management Software (BRMS) written in Java that provides users with a variety of features like Business Rule Engine, Web authoring, Rules Management Application, and runtime support for Decision Model and Notation models.

Drools are split into two parts: ⦁

Authoring – It involves the development of rules files.

⦁

Runtime – It involves the creation of working memory and handling the activation.

What is Rule?

Rules are parts of knowledge often expressed as, “When specific conditions occur, then do some tasks.”

The most crucial part of a rule is it’s when part. Once when part is satisfied, then the part is triggered.

Syntax: When <Condition is true> Then <Take desired Action>

Drools Rule Engine Drools Rule Engine is a rule-based approach to implement an Expert system in the Drools software. The Rule engine provides Expert systems which are knowledge-based systems that help you to make decisions like what to do and how to do it. It gathers knowledge into a knowledge base that can be used for reasoning.

Why use Drools Rule Engine?

Here, are prime reasons for using Drools rules engine: ⦁

Rules are easy to understand for developers and business analysts.

⦁

Rules are easily maintainable.

⦁

Rules can be modified and deployed without bringing down the application.

⦁

Externalizes the business logic from the comparatively static codebase.

⦁

Rules allow you to create a warehouse of knowledge which is executable in form.

Disadvantages of Rules Engine Here, are drawbacks/ cons of using rules engine: ⦁

Lots of learning effort requires by developers to know this method of programming

⦁

Rule engine is not a secure method to troubleshoot issues.

⦁

Needs to understand the working of rule engine to consumes more memory

⦁

There are a wide set of rules for a complex branching.

Spring Boot Drools Rule Engine Example The Drools is an open-source business rule management system that can be integrated easily with the spring boot application.

The KIE project supports the integration of the drools with other technologies like the spring boot framework.

Configure the drools application Create a configuration java class with the name DroolsConfig under config package.

Add the below configuration to the java class.

DroolsConfig.java

Add the model class Create a model class with the name Order and define the below fields.

We receive this class as a request object to the rule engine and, we send these fields as the input to defined rules to set appropriate discount amount for the given customer order.

Order.java

Define the drools rules Create the drools rules inside a file with the name customer-discount.drl. Add the file under the directory /src/main/resources/rules.

Customer-discount.drl

We need to import the models that are being used in the DRL file.

The DRL file can contain one or multiple rules. We can use the mvel syntax to specify the rules. Also, each rule can be described with a description using the rule keyword.

We can use when-then syntax to define the conditions for a rule.

Based on the input values of the Order request, we are adding discount to the result. If none of the defined rule is applied, then the default value will be returned as a discount.

Conclusion In this article, we learned about drools rule system and how to create the drools rule engine using the spring boot framework.

We also learned how we can use the DRL files to define the business rules.

Originally published by: Drools Rule Management System with Spring Boot