Created
July 17, 2016 19:24
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scala wrapper for hadoop remote iterator
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case class RemoteIteratorWrapper[T](underlying: org.apache.hadoop.fs.RemoteIterator[T]) extends scala.collection.AbstractIterator[T] with scala.collection.Iterator[T] { | |
def hasNext = underlying.hasNext | |
def next() = underlying.next() | |
} | |
object Conversions { | |
implicit def remoteIterator2ScalaIterator[T](underlying: org.apache.hadoop.fs.RemoteIterator[T]) : scala.collection.Iterator[T] = RemoteIteratorWrapper[T](underlying) | |
} |
what about this:
import org.apache.hadoop.fs.RemoteIterator
/**
* Converts RemoteIterator from Hadoop to Scala Iterator that provides all the familiar functions such as map,
* filter, foreach, etc.
*
* @param underlying The RemoteIterator that needs to be wrapped
* @tparam T Items inside the iterator
* @return Standard Scala Iterator
*/
implicit def convertToScalaIterator[T](underlying: RemoteIterator[T]): Iterator[T] = {
case class wrapper(underlying: RemoteIterator[T]) extends Iterator[T] {
override def hasNext = underlying.hasNext
override def next = underlying.next
}
wrapper(underlying)
}
Here is a usage example:
val fs = FileSystem.get(spark.sparkContext.hadoopConfiguration)
val hdfsPath = new Path(basePath)
fs.mkdirs(hdfsPath)
import Conversions._
fs.listFiles(hdfsPath, true).foreach(x => println(s"found file ${x.getPath.toUri}"))
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How to use it?