Flink学习27:驱逐器

import org.apache.flink.api.common.eventtime.{SerializableTimestampAssigner, WatermarkStrategy}
import org.apache.flink.api.common.serialization.SimpleStringSchema
import org.apache.flink.api.scala.createTypeInformation
import org.apache.flink.streaming.api.TimeCharacteristic
import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment
import org.apache.flink.streaming.api.scala.function.ProcessWindowFunction
import org.apache.flink.streaming.api.windowing.evictors.Evictor
import org.apache.flink.streaming.api.windowing.time.Time
import org.apache.flink.streaming.api.windowing.windows.TimeWindow
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer
import org.apache.flink.streaming.runtime.operators.windowing.TimestampedValue
import org.apache.flink.util.Collector
import trigger.StockPrice

import java.{lang, util}
import java.time.Duration
import java.util.Properties

object evictor {


  def main(args: Array[String]): Unit = {

    //env
    val env = StreamExecutionEnvironment.getExecutionEnvironment

    //set parallel
    env.setParallelism(1)

    //set event time
    env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)

    //creat ds

    //for kafka connect
    val kafkaProps = new Properties()

    //set ip
    kafkaProps.setProperty("bootstrap.servers", "10.10.10.10:9092")

    //group
    kafkaProps.setProperty("group.id", "gksk-bigdata")

    val kafkaSource = new FlinkKafkaConsumer[String]("stockPrice", new SimpleStringSchema, kafkaProps)

    //set offset
    kafkaSource.setStartFromEarliest()

    //auto commit offset
    kafkaSource.setCommitOffsetsOnCheckpoints(true)

    //band datasource
    val ds = env.addSource(kafkaSource)

    //trans
    val stockPriceDS = ds.map(s => s.split(","))
      .map(s => StockPrice(s(0).toString, s(1).toLong, s(2).toDouble))

    //water mark
    val sumedDS = stockPriceDS.assignTimestampsAndWatermarks(

      //set water mark 0
      WatermarkStrategy
        .forBoundedOutOfOrderness[StockPrice](Duration.ofSeconds(0))
        .withTimestampAssigner(new SerializableTimestampAssigner[StockPrice] {
          override def extractTimestamp(t: StockPrice, l: Long): Long = t.timeStamp
        })
    ).keyBy(s => s.stockId)
      .timeWindow(Time.seconds(2))

      //evictor
      .evictor(new MyEvictor())
      .process(new MyProcessWindowsFunc())

    //print
    sumedDS.print()

    //execute
    env.execute()


  }


  class MyEvictor() extends Evictor[StockPrice,TimeWindow](){
    override def evictBefore(iterable: lang.Iterable[TimestampedValue[StockPrice]], i: Int, w: TimeWindow, evictorContext: Evictor.EvictorContext): Unit = {

      //create the object, which contain (dataObject, timeStamp)
      val ite: util.Iterator[TimestampedValue[StockPrice]] = iterable.iterator()

      //
      while (ite.hasNext){

        //get the dataSource's object
        val element: TimestampedValue[StockPrice] = ite.next()

        println("now the stockPrice is :"+ element.getValue().price)

        //remove illegal data
        if(element.getValue.price <= 0){
          println("illegal price :"+ element.getValue.price)

          ite.remove()
        }

      }
    }

    override def evictAfter(iterable: lang.Iterable[TimestampedValue[StockPrice]], i: Int, w: TimeWindow, evictorContext: Evictor.EvictorContext): Unit = {
      //do nothing
    }
  }


  //get each stock's avg price
  class MyProcessWindowsFunc() extends ProcessWindowFunction[StockPrice, (String,Double), String, TimeWindow]() {

    //process Function will be called, while timeWindow is close,
    // (keybyed stream: each group once )
    //so,if data is big,it's inappropriate to use Process func
    override def process(key: String, context: Context, elements: Iterable[StockPrice], out: Collector[(String, Double)]): Unit = {

      //ps: all timeWindow's data will save to iterable,that is big deal

      //sum
      var sumPrice = 0.0
      elements.foreach(s => {
        sumPrice = sumPrice + s.price
      })

      //stock price's avg
      out.collect(key, sumPrice/elements.size)

    }
  }





}