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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* 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,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package spark.rdd
import spark.{RDD, SparkContext, SparkEnv, Partition, TaskContext}
import spark.storage.BlockManager
private[spark] class BlockRDDPartition(val blockId: String, idx: Int) extends Partition {
val index = idx
}
private[spark]
class BlockRDD[T: ClassManifest](sc: SparkContext, @transient blockIds: Array[String])
extends RDD[T](sc, Nil) {
@transient lazy val locations_ = BlockManager.blockIdsToExecutorLocations(blockIds, SparkEnv.get)
override def getPartitions: Array[Partition] = (0 until blockIds.size).map(i => {
new BlockRDDPartition(blockIds(i), i).asInstanceOf[Partition]
}).toArray
override def compute(split: Partition, context: TaskContext): Iterator[T] = {
val blockManager = SparkEnv.get.blockManager
val blockId = split.asInstanceOf[BlockRDDPartition].blockId
blockManager.get(blockId) match {
case Some(block) => block.asInstanceOf[Iterator[T]]
case None =>
throw new Exception("Could not compute split, block " + blockId + " not found")
}
}
override def getPreferredLocations(split: Partition): Seq[String] =
locations_(split.asInstanceOf[BlockRDDPartition].blockId)
}
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