Scala example source code file (CanBuildFrom.scala)

This example Scala source code file (CanBuildFrom.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

annotation, builder, canbuildfrom, cannot, elem, from, to

The CanBuildFrom.scala Scala example source code

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


package scala
package collection
package generic

import mutable.Builder
import scala.annotation.implicitNotFound

/** A base trait for builder factories.
 *
 *  @tparam From  the type of the underlying collection that requests
 *                a builder to be created.
 *  @tparam Elem  the element type of the collection to be created.
 *  @tparam To    the type of the collection to be created.
 *
 *  @see [[scala.collection.mutable.Builder]]
 *  @author Martin Odersky
 *  @author Adriaan Moors
 *  @since 2.8
 */
@implicitNotFound(msg = "Cannot construct a collection of type ${To} with elements of type ${Elem} based on a collection of type ${From}.")
trait CanBuildFrom[-From, -Elem, +To] {

  /** Creates a new builder on request of a collection.
   *  @param from  the collection requesting the builder to be created.
   *  @return a builder for collections of type `To` with element type `Elem`.
   *          The collections framework usually arranges things so
   *          that the created builder will build the same kind of collection
   *          as `from`.
   */
  def apply(from: From): Builder[Elem, To]

  /** Creates a new builder from scratch.
   *
   *  @return a builder for collections of type `To` with element type `Elem`.
   *  @see scala.collection.breakOut
   */
  def apply(): Builder[Elem, To]
}