BookOperator.scala

import java.util

import io.radanalytics.operator.common.{AbstractOperator, EntityInfo, Operator}

import scala.beans.BeanProperty
import scala.jdk.CollectionConverters._

class Book(@BeanProperty var title: String,
           @BeanProperty var authors: util.List[String])
    extends EntityInfo {
  def this() = this(null, null)
  override def toString: String =
    s"Book(namespace=$namespace, name=$name, title=$title, authors=(${Option(authors).map(_.asScala.mkString(", ")).orNull}))"
}

@Operator(forKind = classOf[Book], prefix = "myoperator.example.com")
class BookOperator extends AbstractOperator[Book] {
  override def onAdd(entity: Book): Unit = println(s"Added a book $entity")
  override def onDelete(entity: Book): Unit = println(s"Deleted a book $entity")
}

build.sbt

scalaVersion := "2.13.0"
libraryDependencies ++= Seq("io.radanalytics" % "abstract-operator" % "0.6.6")
mainClass in Compile := Some("io.radanalytics.operator.Entrypoint")

mybook.yaml

apiVersion: myoperator.example.com/v1
kind: Book
metadata:
  name: moby-dick
spec:
  title: Moby Dick
  authors:
    - Herman Melville
    - Takashi Kawachi