2010-06-17 15:49:42 -04:00
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package spark
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2011-02-27 17:27:12 -05:00
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import java.io.EOFException
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import java.net.URL
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import java.io.ObjectInputStream
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2010-06-17 15:49:42 -04:00
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import java.util.concurrent.atomic.AtomicLong
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import java.util.HashSet
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2010-08-18 18:25:57 -04:00
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import java.util.Random
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2010-06-17 15:49:42 -04:00
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import scala.collection.mutable.ArrayBuffer
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import scala.collection.mutable.Map
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2010-10-03 23:28:20 -04:00
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import scala.collection.mutable.HashMap
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2010-06-17 15:49:42 -04:00
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2010-11-04 02:58:53 -04:00
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import SparkContext._
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2010-07-25 23:53:46 -04:00
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import mesos._
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2010-06-17 15:49:42 -04:00
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@serializable
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2010-10-23 18:34:03 -04:00
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abstract class RDD[T: ClassManifest](@transient sc: SparkContext) {
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2011-02-27 22:15:52 -05:00
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// Methods that must be implemented by subclasses
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def splits: Array[Split]
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def compute(split: Split): Iterator[T]
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def preferredLocations(split: Split): Seq[String]
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val dependencies: List[Dependency[_]]
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2011-02-27 02:15:33 -05:00
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2011-02-27 22:15:52 -05:00
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// Optionally overridden by subclasses to specify how they are partitioned
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2011-03-07 02:38:16 -05:00
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val partitioner: Option[Partitioner] = None
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2011-02-27 22:15:52 -05:00
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def context = sc
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// Get a unique ID for this RDD
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val id = sc.newRddId()
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// Variables relating to caching
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private var shouldCache = false
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// Change this RDD's caching
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def cache(): RDD[T] = {
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shouldCache = true
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this
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}
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// Read this RDD; will read from cache if applicable, or otherwise compute
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final def iterator(split: Split): Iterator[T] = {
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if (shouldCache) {
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RDDCache.getOrCompute[T](this, split)
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} else {
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compute(split)
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}
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}
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// Transformations
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2011-02-27 02:15:33 -05:00
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def map[U: ClassManifest](f: T => U): RDD[U] = new MappedRDD(this, sc.clean(f))
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2011-02-27 17:27:12 -05:00
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def flatMap[U: ClassManifest](f: T => Traversable[U]): RDD[U] =
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new FlatMappedRDD(this, sc.clean(f))
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2011-02-27 02:15:33 -05:00
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def filter(f: T => Boolean): RDD[T] = new FilteredRDD(this, sc.clean(f))
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def sample(withReplacement: Boolean, frac: Double, seed: Int): RDD[T] =
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new SampledRDD(this, withReplacement, frac, seed)
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def union(other: RDD[T]): RDD[T] = new UnionRDD(sc, Array(this, other))
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def ++(other: RDD[T]): RDD[T] = this.union(other)
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def glom(): RDD[Array[T]] = new SplitRDD(this)
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def cartesian[U: ClassManifest](other: RDD[U]): RDD[(T, U)] =
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new CartesianRDD(sc, this, other)
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def groupBy[K](func: T => K, numSplits: Int): RDD[(K, Seq[T])] =
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this.map(t => (func(t), t)).groupByKey(numSplits)
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def groupBy[K](func: T => K): RDD[(K, Seq[T])] =
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groupBy[K](func, sc.numCores)
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// Parallel operations
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def foreach(f: T => Unit) {
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val cleanF = sc.clean(f)
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sc.runJob(this, (iter: Iterator[T]) => iter.foreach(cleanF))
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}
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def collect(): Array[T] = {
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val results = sc.runJob(this, (iter: Iterator[T]) => iter.toArray)
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Array.concat(results: _*)
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}
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def reduce(f: (T, T) => T): T = {
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val cleanF = sc.clean(f)
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2011-02-27 02:15:33 -05:00
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val reducePartition: Iterator[T] => Option[T] = iter => {
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if (iter.hasNext)
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Some(iter.reduceLeft(f))
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else
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None
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}
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val options = sc.runJob(this, reducePartition)
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val results = new ArrayBuffer[T]
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for (opt <- options; elem <- opt)
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results += elem
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if (results.size == 0)
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throw new UnsupportedOperationException("empty collection")
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else
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return results.reduceLeft(f)
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}
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2011-02-27 22:15:52 -05:00
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def count(): Long = {
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2011-05-13 13:41:34 -04:00
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sc.runJob(this, (iter: Iterator[T]) => {
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var result = 0L
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while (iter.hasNext) {
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result += 1L
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iter.next
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}
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result
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}).sum
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2011-02-27 22:15:52 -05:00
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}
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def toArray(): Array[T] = collect()
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2011-03-07 02:38:16 -05:00
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override def toString(): String = {
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"%s(%d)".format(getClass.getSimpleName, id)
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}
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2010-06-17 15:49:42 -04:00
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2011-02-27 22:15:52 -05:00
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// TODO: Reimplement these to properly build any shuffle dependencies on
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// the cluster rather than attempting to compute a partiton on the master
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2011-02-27 17:27:12 -05:00
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/*
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def take(num: Int): Array[T] = {
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if (num == 0)
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return new Array[T](0)
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val buf = new ArrayBuffer[T]
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for (split <- splits; elem <- iterator(split)) {
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buf += elem
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if (buf.length == num)
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return buf.toArray
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}
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return buf.toArray
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}
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def first: T = take(1) match {
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case Array(t) => t
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case _ => throw new UnsupportedOperationException("empty collection")
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}
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2011-02-27 17:27:12 -05:00
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*/
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}
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2010-08-31 15:08:09 -04:00
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class MappedRDD[U: ClassManifest, T: ClassManifest](
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prev: RDD[T], f: T => U)
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extends RDD[U](prev.context) {
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override def splits = prev.splits
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override def preferredLocations(split: Split) = prev.preferredLocations(split)
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override val dependencies = List(new OneToOneDependency(prev))
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override def compute(split: Split) = prev.iterator(split).map(f)
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}
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class FlatMappedRDD[U: ClassManifest, T: ClassManifest](
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prev: RDD[T], f: T => Traversable[U])
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extends RDD[U](prev.context) {
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override def splits = prev.splits
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override def preferredLocations(split: Split) = prev.preferredLocations(split)
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override val dependencies = List(new OneToOneDependency(prev))
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override def compute(split: Split) = prev.iterator(split).toStream.flatMap(f).iterator
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}
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2010-08-31 15:08:09 -04:00
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class FilteredRDD[T: ClassManifest](
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prev: RDD[T], f: T => Boolean)
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extends RDD[T](prev.context) {
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override def splits = prev.splits
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override def preferredLocations(split: Split) = prev.preferredLocations(split)
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override val dependencies = List(new OneToOneDependency(prev))
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override def compute(split: Split) = prev.iterator(split).filter(f)
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}
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2010-10-17 00:21:16 -04:00
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class SplitRDD[T: ClassManifest](prev: RDD[T])
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extends RDD[Array[T]](prev.context) {
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override def splits = prev.splits
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override def preferredLocations(split: Split) = prev.preferredLocations(split)
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override val dependencies = List(new OneToOneDependency(prev))
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override def compute(split: Split) = Iterator.fromArray(Array(prev.iterator(split).toArray))
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}
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2010-10-03 23:28:20 -04:00
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2010-11-04 02:51:11 -04:00
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@serializable class PairRDDExtras[K, V](self: RDD[(K, V)]) {
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def reduceByKeyToDriver(func: (V, V) => V): Map[K, V] = {
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def mergeMaps(m1: HashMap[K, V], m2: HashMap[K, V]): HashMap[K, V] = {
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for ((k, v) <- m2) {
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m1.get(k) match {
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case None => m1(k) = v
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case Some(w) => m1(k) = func(w, v)
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}
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}
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return m1
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}
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self.map(pair => HashMap(pair)).reduce(mergeMaps)
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}
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2010-11-04 00:27:24 -04:00
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2010-11-04 02:51:11 -04:00
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def combineByKey[C](createCombiner: V => C,
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mergeValue: (C, V) => C,
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mergeCombiners: (C, C) => C,
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numSplits: Int)
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: RDD[(K, C)] =
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{
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val aggregator = new Aggregator[K, V, C](createCombiner, mergeValue, mergeCombiners)
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val partitioner = new HashPartitioner(numSplits)
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new ShuffledRDD(self, aggregator, partitioner)
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}
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def reduceByKey(func: (V, V) => V, numSplits: Int): RDD[(K, V)] = {
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combineByKey[V]((v: V) => v, func, func, numSplits)
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}
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def groupByKey(numSplits: Int): RDD[(K, Seq[V])] = {
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def createCombiner(v: V) = ArrayBuffer(v)
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def mergeValue(buf: ArrayBuffer[V], v: V) = buf += v
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def mergeCombiners(b1: ArrayBuffer[V], b2: ArrayBuffer[V]) = b1 ++= b2
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val bufs = combineByKey[ArrayBuffer[V]](
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createCombiner _, mergeValue _, mergeCombiners _, numSplits)
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bufs.asInstanceOf[RDD[(K, Seq[V])]]
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}
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def join[W](other: RDD[(K, W)], numSplits: Int): RDD[(K, (V, W))] = {
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val vs: RDD[(K, Either[V, W])] = self.map { case (k, v) => (k, Left(v)) }
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val ws: RDD[(K, Either[V, W])] = other.map { case (k, w) => (k, Right(w)) }
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(vs ++ ws).groupByKey(numSplits).flatMap {
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case (k, seq) => {
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val vbuf = new ArrayBuffer[V]
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val wbuf = new ArrayBuffer[W]
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seq.foreach(_ match {
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case Left(v) => vbuf += v
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case Right(w) => wbuf += w
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})
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for (v <- vbuf; w <- wbuf) yield (k, (v, w))
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}
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}
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}
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def combineByKey[C](createCombiner: V => C,
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mergeValue: (C, V) => C,
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mergeCombiners: (C, C) => C)
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: RDD[(K, C)] = {
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combineByKey(createCombiner, mergeValue, mergeCombiners, numCores)
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}
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def reduceByKey(func: (V, V) => V): RDD[(K, V)] = {
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reduceByKey(func, numCores)
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}
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def groupByKey(): RDD[(K, Seq[V])] = {
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groupByKey(numCores)
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}
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2010-11-04 02:51:11 -04:00
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def join[W](other: RDD[(K, W)]): RDD[(K, (V, W))] = {
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join(other, numCores)
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}
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def numCores = self.context.numCores
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def collectAsMap(): Map[K, V] = HashMap(self.collect(): _*)
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2011-03-06 22:27:03 -05:00
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2011-04-12 22:51:58 -04:00
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def mapValues[U](f: V => U): RDD[(K, U)] = {
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val cleanF = self.context.clean(f)
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new MappedValuesRDD(self, cleanF)
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}
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2011-04-12 22:51:58 -04:00
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def flatMapValues[U](f: V => Traversable[U]): RDD[(K, U)] = {
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val cleanF = self.context.clean(f)
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new FlatMappedValuesRDD(self, cleanF)
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}
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2011-03-07 02:38:16 -05:00
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def groupWith[W](other: RDD[(K, W)]): RDD[(K, (Seq[V], Seq[W]))] = {
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val part = self.partitioner match {
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case Some(p) => p
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case None => new HashPartitioner(numCores)
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}
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new CoGroupedRDD[K](Seq(self.asInstanceOf[RDD[(_, _)]], other.asInstanceOf[RDD[(_, _)]]), part).map {
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case (k, Seq(vs, ws)) =>
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(k, (vs.asInstanceOf[Seq[V]], ws.asInstanceOf[Seq[W]]))
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}
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}
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def groupWith[W1, W2](other1: RDD[(K, W1)], other2: RDD[(K, W2)])
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: RDD[(K, (Seq[V], Seq[W1], Seq[W2]))] = {
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val part = self.partitioner match {
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case Some(p) => p
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case None => new HashPartitioner(numCores)
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}
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new CoGroupedRDD[K](
|
|
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Seq(self.asInstanceOf[RDD[(_, _)]],
|
|
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|
other1.asInstanceOf[RDD[(_, _)]],
|
|
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|
other2.asInstanceOf[RDD[(_, _)]]),
|
|
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|
part).map {
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|
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case (k, Seq(vs, w1s, w2s)) =>
|
|
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|
(k, (vs.asInstanceOf[Seq[V]], w1s.asInstanceOf[Seq[W1]], w2s.asInstanceOf[Seq[W2]]))
|
|
|
|
}
|
|
|
|
}
|
2010-10-03 23:28:20 -04:00
|
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|
}
|
2011-03-06 22:27:03 -05:00
|
|
|
|
|
|
|
class MappedValuesRDD[K, V, U](
|
|
|
|
prev: RDD[(K, V)], f: V => U)
|
|
|
|
extends RDD[(K, U)](prev.context) {
|
|
|
|
override def splits = prev.splits
|
|
|
|
override def preferredLocations(split: Split) = prev.preferredLocations(split)
|
|
|
|
override val dependencies = List(new OneToOneDependency(prev))
|
|
|
|
override val partitioner = prev.partitioner
|
2011-04-12 22:51:58 -04:00
|
|
|
override def compute(split: Split) =
|
|
|
|
prev.iterator(split).map{case (k, v) => (k, f(v))}
|
|
|
|
}
|
|
|
|
|
|
|
|
class FlatMappedValuesRDD[K, V, U](
|
|
|
|
prev: RDD[(K, V)], f: V => Traversable[U])
|
|
|
|
extends RDD[(K, U)](prev.context) {
|
|
|
|
override def splits = prev.splits
|
|
|
|
override def preferredLocations(split: Split) = prev.preferredLocations(split)
|
|
|
|
override val dependencies = List(new OneToOneDependency(prev))
|
|
|
|
override val partitioner = prev.partitioner
|
|
|
|
override def compute(split: Split) = {
|
|
|
|
prev.iterator(split).toStream.flatMap {
|
|
|
|
case (k, v) => f(v).map(x => (k, x))
|
|
|
|
}.iterator
|
|
|
|
}
|
|
|
|
}
|