org.apache.spark.sql.execution.datasources.v2.DataSourceRDD.scala Maven / Gradle / Ivy
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* contributor license agreements. See the NOTICE file distributed with
* this work for additional information 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
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.spark.sql.execution.datasources.v2
import scala.collection.JavaConverters._
import scala.reflect.ClassTag
import org.apache.spark.{InterruptibleIterator, Partition, SparkContext, TaskContext}
import org.apache.spark.rdd.RDD
import org.apache.spark.sql.sources.v2.reader.DataReaderFactory
class DataSourceRDDPartition[T : ClassTag](val index: Int, val readerFactory: DataReaderFactory[T])
extends Partition with Serializable
class DataSourceRDD[T: ClassTag](
sc: SparkContext,
@transient private val readerFactories: java.util.List[DataReaderFactory[T]])
extends RDD[T](sc, Nil) {
override protected def getPartitions: Array[Partition] = {
readerFactories.asScala.zipWithIndex.map {
case (readerFactory, index) => new DataSourceRDDPartition(index, readerFactory)
}.toArray
}
override def compute(split: Partition, context: TaskContext): Iterator[T] = {
val reader = split.asInstanceOf[DataSourceRDDPartition[T]].readerFactory.createDataReader()
context.addTaskCompletionListener(_ => reader.close())
val iter = new Iterator[T] {
private[this] var valuePrepared = false
override def hasNext: Boolean = {
if (!valuePrepared) {
valuePrepared = reader.next()
}
valuePrepared
}
override def next(): T = {
if (!hasNext) {
throw new java.util.NoSuchElementException("End of stream")
}
valuePrepared = false
reader.get()
}
}
new InterruptibleIterator(context, iter)
}
override def getPreferredLocations(split: Partition): Seq[String] = {
split.asInstanceOf[DataSourceRDDPartition[T]].readerFactory.preferredLocations()
}
}