measure/src/main/scala/org/apache/griffin/measure/context/DataFrameCache.scala

/*
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regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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specific language governing permissions and limitations
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*/
package org.apache.griffin.measure.context

import org.apache.griffin.measure.Loggable
import org.apache.spark.sql.DataFrame

import scala.collection.concurrent.{Map => ConcMap}
import scala.collection.mutable.{MutableList, Map => MutableMap}

/**
  * cache and unpersist dataframes
  */
case class DataFrameCache() extends Loggable {

  val dataFrames: MutableMap[String, DataFrame] = MutableMap()
  val trashDataFrames: MutableList[DataFrame] = MutableList()

  private def trashDataFrame(df: DataFrame): Unit = {
    trashDataFrames += df
  }
  private def trashDataFrames(dfs: Seq[DataFrame]): Unit = {
    trashDataFrames ++= dfs
  }

  def cacheDataFrame(name: String, df: DataFrame): Unit = {
    info(s"try to cache data frame ${name}")
    dataFrames.get(name) match {
      case Some(odf) => {
        trashDataFrame(odf)
        dataFrames += (name -> df)
        df.cache
        info("cache after replace old df")
      }
      case _ => {
        dataFrames += (name -> df)
        df.cache
        info("cache after replace no old df")
      }
    }
  }

  def uncacheDataFrame(name: String): Unit = {
    dataFrames.get(name).foreach(df => trashDataFrame(df))
    dataFrames -= name
  }
  def uncacheAllDataFrames(): Unit = {
    trashDataFrames(dataFrames.values.toSeq)
    dataFrames.clear
  }

  def clearAllTrashDataFrames(): Unit = {
    trashDataFrames.foreach(_.unpersist)
    trashDataFrames.clear
  }

}