Scala example source code file (Hashing.scala)

This example Scala source code file (Hashing.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, default, hashing, int, no, serializable, t

The Hashing.scala Scala example source code

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

package scala
package util.hashing

import scala.annotation.implicitNotFound

/** `Hashing` is a trait whose instances each represent a strategy for hashing
  * instances of a type.
  *
  * `Hashing`'s companion object defines a default hashing strategy for all
  * objects - it calls their `##` method.
  *
  * Note: when using a custom `Hashing`, make sure to use it with the `Equiv`
  * such that if any two objects are equal, then their hash codes must be equal.
  *
  * @since 2.10
  */
@implicitNotFound(msg = "No implicit Hashing defined for ${T}.")
trait Hashing[T] extends Serializable {
  def hash(x: T): Int
}

object Hashing {
  final class Default[T] extends Hashing[T] {
    def hash(x: T) = x.##
  }

  implicit def default[T] = new Default[T]

  def fromFunction[T](f: T => Int) = new Hashing[T] {
    def hash(x: T) = f(x)
  }
}