Scala example source code file (Parallelizable.scala)

This example Scala source code file (Parallelizable.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

any, combiner, parallel, parallelizable, parrepr, traversableonce

The Parallelizable.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala
package collection

import parallel.Combiner

/** This trait describes collections which can be turned into parallel collections
 *  by invoking the method `par`. Parallelizable collections may be parametrized with
 *  a target type different than their own.
 *
 *  @tparam A            the type of the elements in the collection
 *  @tparam ParRepr      the actual type of the collection, which has to be parallel
 */
trait Parallelizable[+A, +ParRepr <: Parallel] extends Any {

  def seq: TraversableOnce[A]

  /** Returns a parallel implementation of this collection.
   *
   *  For most collection types, this method creates a new parallel collection by copying
   *  all the elements. For these collection, `par` takes linear time. Mutable collections
   *  in this category do not produce a mutable parallel collection that has the same
   *  underlying dataset, so changes in one collection will not be reflected in the other one.
   *
   *  Specific collections (e.g. `ParArray` or `mutable.ParHashMap`) override this default
   *  behaviour by creating a parallel collection which shares the same underlying dataset.
   *  For these collections, `par` takes constant or sublinear time.
   *
   *  All parallel collections return a reference to themselves.
   *
   *  @return  a parallel implementation of this collection
   */
  def par: ParRepr = {
    val cb = parCombiner
    for (x <- seq) cb += x
    cb.result()
  }

  /** The default `par` implementation uses the combiner provided by this method
   *  to create a new parallel collection.
   *
   *  @return  a combiner for the parallel collection of type `ParRepr`
   */
  protected[this] def parCombiner: Combiner[A, ParRepr]
}