1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection.parallel.mutable
import scala.collection.generic.Growable
import scala.collection.generic.Sizing
import scala.collection.mutable.ArrayBuffer
import scala.collection.parallel.Combiner
/** Implements combining contents of two combiners
* by postponing the operation until `result` method is called. It chains
* the leaf results together instead of evaluating the actual collection.
*
* @tparam Elem the type of the elements in the combiner
* @tparam To the type of the collection the combiner produces
* @tparam Buff the type of the buffers that contain leaf results and this combiner chains together
*/
trait LazyCombiner[Elem, +To, Buff <: Growable[Elem] with Sizing] extends Combiner[Elem, To] {
//self: scala.collection.parallel.EnvironmentPassingCombiner[Elem, To] =>
val chain: ArrayBuffer[Buff]
val lastbuff = chain.last
def +=(elem: Elem) = { lastbuff += elem; this }
def result: To = allocateAndCopy
def clear() = { chain.clear() }
def combine[N <: Elem, NewTo >: To](other: Combiner[N, NewTo]): Combiner[N, NewTo] = if (this ne other) {
if (other.isInstanceOf[LazyCombiner[_, _, _]]) {
val that = other.asInstanceOf[LazyCombiner[Elem, To, Buff]]
newLazyCombiner(chain ++= that.chain)
} else throw new UnsupportedOperationException("Cannot combine with combiner of different type.")
} else this
def size = chain.foldLeft(0)(_ + _.size)
/** Method that allocates the data structure and copies elements into it using
* `size` and `chain` members.
*/
def allocateAndCopy: To
def newLazyCombiner(buffchain: ArrayBuffer[Buff]): LazyCombiner[Elem, To, Buff]
}
|
