Drools constraints analysis / published by https://github.com/dacr/code-examples-manager #581eb9be-b67a-4c2f-87cf-412b681c3e0c/b3255aca46abcf11c87371a81112774da24ad1dd

drools-kb-understanding-constraints-limitations.sc

// summary : Drools constraints analysis
// keywords : scala, drools, mvel, scalatest, ai, knowledgebase, @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 : 581eb9be-b67a-4c2f-87cf-412b681c3e0c
// created-on : 2020-01-10T08:06:29+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.5.1"
//> using dep "fr.janalyse::drools-scripting:1.2.0"
//> using dep "org.scalatest::scalatest:3.2.19"
// ---------------------

import fr.janalyse.droolscripting.*, org.scalatest.*, wordspec.*, matchers.*, OptionValues.*

object UnderstandingRulesConstraintLimits extends AnyWordSpec with should.Matchers {
  override def suiteName: String = "UnderstandingRulesConstraintLimits"
  def checkOK(drl:String):Unit = {
    val engine = DroolsEngine(drl, DroolsEngineConfig(equalsWithIdentity=false, eventProcessingMode = StreamMode, pseudoClock = false))
    engine.fireAllRules()
    engine.strings shouldBe List("OK")
  }
  "DROOLS" should {
    // ======================================================================
    "support attribute changes without infinite loop for attributes not used in any constraints " in checkOK {
      info("ALWAYS PLACE ATTRIBUTE NAME IN THE LHS PART OF CONSTRAINTS")
      info("WRITE : origin == $origin, card == $card")
      info("DON'T WRITE : $origin == origin, $card == card")
      info("This is a 'known' limitation of the property reactivity analysis")
      info("TO AVOID RULE INFINITE RECURSION")
      info("Check : https://issues.redhat.com/browse/DROOLS-4909")
      info("Check : https://issues.redhat.com/browse/DROOLS-4288")
      """package dummy
        |dialect "mvel"
        |
        |declare Init id:String end
        |declare Origin id:String end
        |declare Card id:String end
        |declare Context origin:Origin card:Card end
        |
        |declare Metric origin:Origin card:Card name:String value:double end
        |declare Issue origin:Origin card:Card desc:String risk:int category:String end
        |
        |rule "init" when then  insert(new Init("abcd")) end
        |
        |rule "origin" when Init($id:id) then
        |  insertLogical(new Context(new Origin($id), new Card($id)))
        |end
        |
        |rule "init counter metric"
        |when
        |  Context($o:origin, $c:card)
        |  not Metric($o == origin, $c == card, name == "counter")
        |then
        |  insert(new Metric($o, $c, "counter", 0))
        |end
        |
        |//-----------------
        |rule "reset"
        |when
        |  $context:Context($origin:origin, $card:card)
        |  not Issue(origin == $origin, $card == card, category!="scoring")
        |  $metric:Metric(name == "counter", origin == $origin, card == $card)
        |then
        |  modify($metric) {
        |    setValue(100);
        |  };
        |end
        |
        |//-----------------
        |rule "end" salience -10 when Metric(value == 100) then insert("OK"); end
        |
        |""".stripMargin
    }
  }
}
UnderstandingRulesConstraintLimits.execute()