dacr / drools-scripting

Drools made easy to use for scripting or testing purposes

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Drools scripting Build Status License Maven

Drools made easy to use for scripting or testing purposes.

This library allows you to easily design proof of concepts based of the drools expert system. It greatly simplifies how you can quickly write drools based code examples or small experiments.

Just insert JSON facts into your drools working memory, and use the available engine methods to interact with the expert system and extract data from it. Data extraction can be done through simple accessors or through the JSON format. Check the documented methods in the DroolsEngine class or take a look to the large amount of example I've made available. (Most of them can be run directly by using the great ammonite REPL solution from Li Haoyi)

An hello world drools example runnable with ammonite :

import $ivy.`fr.janalyse::drools-scripting:1.0.11`, $ivy.`org.scalatest::scalatest:3.2.2`
import fr.janalyse.droolscripting._, org.scalatest.flatspec._, org.scalatest.matchers._

object HelloTest extends AnyFlatSpec with should.Matchers {
  "Drools" should "say hello" in {
    val drl =
      """package test
        |rule "hello" when
        |then
        |  insert("HELLO WORLD");
        |end
        |""".stripMargin
    val engine = DroolsEngine(drl)
    engine.fireAllRules()
    engine.strings shouldBe List("HELLO WORLD")
  }
}
HelloTest.execute()

or an other one runnable with ammonite :

import $ivy.`fr.janalyse::drools-scripting:1.0.11`, $ivy.`org.scalatest::scalatest:3.2.2`
import fr.janalyse.droolscripting._, org.scalatest._, flatspec._, matchers._, OptionValues._

object HelloTest extends AnyFlatSpec with should.Matchers {
  "Drools" should "say hello" in {
    val drl =
      """package test
        |
        |declare Someone
        |  name:String
        |end
        |
        |declare Message
        |  message:String
        |end
        |
        |rule "hello" when
        |  Someone($name:name)
        |then
        |  insert(new Message("HELLO "+$name));
        |end
        |""".stripMargin
    val engine = DroolsEngine(drl)
    engine.insertJson("""{"name":"John"}""","test.Someone")
    engine.fireAllRules()
    val msgOption = engine.getModelFirstInstanceAttribute("test.Message", "message")
    msgOption.value shouldBe "HELLO John"
  }
}
HelloTest.execute()