Understanding insertLogical, aggregates in the context of drools events reasoning, keeping up to date a computed value / published by https://github.com/dacr/code-examples-manager #a0e2caf5-ca1b-4d9a-91cf-62c6aa7623be/832f1025dbd4f6f4fa96439bb34c394f4c9a989d

drools-insertLogical-aggregate-expires.sc

// summary : Understanding insertLogical, aggregates in the context of drools events reasoning, keeping up to date a computed value
// keywords : scala, drools, mvel, scalatest, ai, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : a0e2caf5-ca1b-4d9a-91cf-62c6aa7623be
// created-on : 2018-09-12T21:11:39+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala  "3.3.0"
//> using dep "fr.janalyse::drools-scripting:1.1.0"
//> using dep "org.scalatest::scalatest:3.2.16"
// ---------------------

import fr.janalyse.droolscripting._, org.scalatest._, flatspec._, matchers._, OptionValues._

object SimpleTest extends AnyFlatSpec with should.Matchers {
  override val suiteName = "SimpleTest"

  "drools" should "propagate and expires" in {
    val drl =
      """package testdrools
        |
        |global org.slf4j.Logger logger
        |// --------------------------------------------------------------------
        |declare Hello
        |  name:String
        |  age:int
        |end
        |// --------------------------------------------------------------------
        |declare HelloEvent
        |  @role(event)
        |  @expires(20s)
        |  hello:Hello
        |end
        |// --------------------------------------------------------------------
        |declare Metric
        |  name:String
        |  value:double
        |end
        |// --------------------------------------------------------------------
        |rule "INIT-1"
        |when
        |then
        |  insert(new HelloEvent(new Hello("John", 24)));
        |end
        |// --------------------------------------------------------------------
        |rule "INIT-2"
        |duration 10000
        |when
        |then
        |  insert(new HelloEvent(new Hello("Sarah", 42)));
        |end
        |// --------------------------------------------------------------------
        |rule "TEST-1: hello event to fact"
        |when
        |  HelloEvent($hello:hello)
        |then
        |  insertLogical($hello);
        |end
        |// --------------------------------------------------------------------
        |rule "TEST-1A : init metric container"
        |@Propagation(EAGER)
        |enabled true
        |when
        |  not Metric(name == "averageAge")
        |then
        |  insert(new Metric("averageAge",0.0));
        |end
        |// --------------------------------------------------------------------
        |rule "TEST-1B : hello average age"
        |no-loop
        |enabled true
        |when
        |  exists Hello()
        |  accumulate(Hello($age:age); $avg: average($age))
        |  $metric: Metric(name == "averageAge")
        |then
        |  logger.info("****************** TEST-1B new average age "+ $avg);
        |  modify($metric) {
        |    setValue($avg);
        |  }
        |end
        |// --------------------------------------------------------------------
        |rule "TEST-1C : talk when average age evolves"
        |enabled true
        |when
        |  $metric: Metric(name == "averageAge", $avg:value)
        |then
        |  logger.info("****************** TEST-1C new average age AGAIN"+ $avg);
        |end
        |// --------------------------------------------------------------------
        |rule "TEST-1D : reset average age"
        |no-loop
        |enabled true
        |when
        |  $metric: Metric(name == "averageAge")
        |  not Hello()
        |then
        |  logger.info("****************** TEST-1D average age RESET");
        |  modify($metric) {
        |    setValue(0.0);
        |  }
        |end
        |""".stripMargin
    val config = DroolsEngineConfig(withDroolsLogging = true)
    val engine = DroolsEngine(drl, config)
    engine.fireAllRules() // Only John 24
    engine.getModelFirstInstanceAttribute("testdrools.Metric", "value").value.asInstanceOf[Double] shouldBe 24

    engine.timeShiftInSeconds(12)
    engine.fireAllRules() // John 24 & Sarah 42
    engine.getModelFirstInstanceAttribute("testdrools.Metric", "value").value.asInstanceOf[Double] shouldBe 33

    engine.timeShiftInSeconds(10)
    engine.fireAllRules() // Only Sarah 42
    engine.getModelFirstInstanceAttribute("testdrools.Metric", "value").value.asInstanceOf[Double] shouldBe 42

    engine.timeShiftInSeconds(30)
    engine.fireAllRules() // Nobody
    engine.getModelFirstInstanceAttribute("testdrools.Metric", "value").value.asInstanceOf[Double] shouldBe 0
    engine.getObjects.size shouldBe 1 // The metric container
  }
}

SimpleTest.execute()