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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2011, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.collection
package generic
import mutable.Builder
import language.higherKinds
/** A template class for companion objects of "regular" collection classes
* represent an unconstrained higher-kinded type. Typically
* such classes inherit from trait `GenericTraversableTemplate`.
* @tparam CC The type constructor representing the collection class.
* @see GenericTraversableTemplate
* @author Martin Odersky
* @since 2.8
* @define coll collection
* @define Coll CC
*/
abstract class GenericCompanion[+CC[X] <: GenTraversable[X]] {
/** The underlying collection type with unknown element type */
type Coll = CC[_]
/** The default builder for `$Coll` objects.
* @tparam A the type of the ${coll}'s elements
*/
def newBuilder[A]: Builder[A, CC[A]]
/** An empty collection of type `$Coll[A]`
* @tparam A the type of the ${coll}'s elements
*/
def empty[A]: CC[A] = newBuilder[A].result
/** Creates a $coll with the specified elements.
* @tparam A the type of the ${coll}'s elements
* @param elems the elements of the created $coll
* @return a new $coll with elements `elems`
*/
def apply[A](elems: A*): CC[A] = {
if (elems.isEmpty) empty[A]
else {
val b = newBuilder[A]
b ++= elems
b.result
}
}
}
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