measure/src/main/scala/org/apache/griffin/measure/step/transform/TransformStep.scala

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to you under the Apache License, Version 2.0 (the
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  http://www.apache.org/licenses/LICENSE-2.0

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package org.apache.griffin.measure.step.transform

import scala.collection.mutable.HashSet
import scala.concurrent.duration.Duration
import scala.concurrent.ExecutionContext
import scala.concurrent.Future

import org.apache.griffin.measure.context.DQContext
import org.apache.griffin.measure.step.DQStep
import org.apache.griffin.measure.step.DQStepStatus._
import org.apache.griffin.measure.utils.ThreadUtils

trait TransformStep extends DQStep {

  val rule: String

  val details: Map[String, Any]

  val cache: Boolean

  var status = PENDING

  val parentSteps = new HashSet[TransformStep]

  def doExecute(context: DQContext): Boolean

  def execute(context: DQContext): Boolean = {
    val threadName = Thread.currentThread().getName
    info(threadName + " begin transform step : \n" + debugString())
    // Submit parents Steps
    val parentStepFutures = parentSteps.filter(checkAndUpdateStatus).map { parentStep =>
      Future {
        val result = parentStep.execute(context)
        parentStep.synchronized {
          if (result) {
            parentStep.status = COMPLETE
          } else {
            parentStep.status = FAILED
          }
        }
      }(TransformStep.transformStepContext)
    }
    ThreadUtils.awaitResult(
      Future.sequence(parentStepFutures)(implicitly, TransformStep.transformStepContext),
      Duration.Inf)

    parentSteps.map(step => {
      while (step.status == RUNNING) {
        Thread.sleep(1000L)
      }
    })
    val prepared = parentSteps.foldLeft(true)((ret, step) => ret && step.status == COMPLETE)
    if (prepared) {
      val res = doExecute(context)
      info(threadName + " end transform step : \n" + debugString())
      res
    } else {
      error("Parent transform step failed!")
      false
    }
  }

  def checkAndUpdateStatus(step: TransformStep): Boolean = {
    step.synchronized {
      if (step.status == PENDING) {
        step.status = RUNNING
        true
      } else {
        false
      }
    }
  }

  def debugString(level: Int = 0): String = {
    val stringBuffer = new StringBuilder
    if (level > 0) {
      for (i <- 0 to level - 1) {
        stringBuffer.append("|   ")
      }
      stringBuffer.append("|---")
    }
    stringBuffer.append(name + "\n")
    parentSteps.foreach(parentStep => stringBuffer.append(parentStep.debugString(level + 1)))
    stringBuffer.toString()
  }
}

object TransformStep {
  private[transform] val transformStepContext = ExecutionContext.fromExecutorService(
    ThreadUtils.newDaemonCachedThreadPool("transform-step"))
}