CODEWITHSUNDEEP
scala
Aakash Sharma
Aakash Sharma

Reputation: 13

Scala abstract class function call

I am new to scala and I apologize in advance if the question is stupid. I am browsing through this scala code and I am confused how the following code works 

abstract class ClusterSimulatorDesc(val runTime: Double) {
  def newSimulator(constantThinkTim: Double,
               perTaskThinkTime: Double,
               blackListPercent: Double,
               schedulerWorkloadsToSweepOver: Map[String, Seq[String]],
               workloadToSchedulerMap: Map[String, Seq[String]],
               cellStateDesc: CellStateDesc,
               workloads: Seq[Workload],
               prefillWorkloads: Seq[Workload],
               logging: Boolean = false): ClusterSimulator
}

class ClusterSimulator(val cellState: CellState,
                   val schedulers: Map[String, Scheduler],
                   val workloadToSchedulerMap: Map[String, Seq[String]],
                   val workloads: Seq[Workload],
                   prefillWorkloads: Seq[Workload],
                   logging: Boolean = false,
                   monitorUtilization: Boolean = true,
                   monitoringPeriod: Double = 1.0)
                  extends Simulator(logging) {

Now if i have a function call like:- 

simulatorDesc: ClusterSimulatorDesc
val simulator =
              simulatorDesc.newSimulator(constantThinkTime,
                                         perTaskThinkTime,
                                         blackListPercent,
                                         schedulerWorkloadsToSweepOver,
                                         schedulerWorkloadMap,
                                         workloadDesc.cellStateDesc,
                                         workloads,
                                         prefillWorkloads,
                                         logging)

Now the question I have is, what does "ClusterSimulator" at the end of the abstract class declaration does? And, how does the calling of "newSimulator" function happen, considering that its declared in an abstract class?

Upvotes: 0

Views: 87

Answers (1)

jwvh
jwvh

Reputation: 51271

def newSimulator(....): ClusterSimulator

The method newSimulator(), when invoked, returns an instance of ClusterSimulator.

simulatorDesc: ClusterSimulatorDesc

ClusterSimulatorDesc can't be instantiated because it is abstract, but a class that extends ClusterSimulatorDesc can be instantiated and an instance of that class is also an instance of ClusterSimulatorDesc and can invoke its methods.

Upvotes: 2

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