Scala example source code file (Proxy.scala)

This example Scala source code file (Proxy.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, boolean, int, proxy, t, typed

The Proxy.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2002-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://www.scala-lang.org/           **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala

/** This class implements a simple proxy that forwards all calls to
 *  the public, non-final methods defined in class `Any` to another
 *  object self.  Those methods are:
 *  {{{
 *    def hashCode(): Int
 *    def equals(other: Any): Boolean
 *    def toString(): String
 *  }}}
 *  '''Note:''' forwarding methods in this way will most likely create
 *  an asymmetric equals method, which is not generally recommended.
 *
 *  @author  Matthias Zenger
 *  @version 1.0, 26/04/2004
 */
trait Proxy extends Any {
  def self: Any

  override def hashCode: Int = self.hashCode
  override def equals(that: Any): Boolean = that match {
    case null  => false
    case _     =>
      val x = that.asInstanceOf[AnyRef]
      (x eq this.asInstanceOf[AnyRef]) || (x eq self.asInstanceOf[AnyRef]) || (x equals self)
  }
  override def toString = "" + self
}

object Proxy {
  /** A proxy which exposes the type it is proxying for via a type parameter.
   */
  trait Typed[T] extends Any with Proxy {
    def self: T
  }
}