Scala example source code file (PriorityQueueProxy.scala)

This example Scala source code file (PriorityQueueProxy.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

a, iterator, ordering, priorityqueue, priorityqueueproxy, proxy, proxying, queue, traversableonce, unit

The PriorityQueueProxy.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |                                         **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */


package scala
package collection
package mutable

/** This class servers as a proxy for priority queues. The
 *  elements of the queue have to be ordered in terms of the
 *  `Ordered[T]` class.
 *
 *  @author  Matthias Zenger
 *  @version 1.0, 03/05/2004
 *  @since   1
 */
@deprecated("Proxying is deprecated due to lack of use and compiler-level support.", "2.11.0")
abstract class PriorityQueueProxy[A](implicit ord: Ordering[A]) extends PriorityQueue[A]
         with Proxy
{
  def self: PriorityQueue[A]

  /** Creates a new iterator over all elements contained in this
   *  object.
   *
   *  @return the new iterator
   */
  override def iterator: Iterator[A] = self.iterator

  /** Returns the length of this priority queue.
   */
  override def length: Int = self.length

  /** Checks if the queue is empty.
   *
   *  @return true, iff there is no element in the queue.
   */
  override def isEmpty: Boolean = self.isEmpty

  /** Inserts a single element into the priority queue.
   *
   *  @param  elem        the element to insert
   */
  override def +=(elem: A): this.type = { self += elem; this }

  /** Adds all elements provided by an iterator into the priority queue.
   *
   *  @param  it        an iterator
   */
  override def ++=(it: TraversableOnce[A]): this.type = {
    self ++= it
    this
  }

  /** Adds all elements to the queue.
   *
   *  @param  elems       the elements to add.
   */
  override def enqueue(elems: A*): Unit = self ++= elems

  /** Returns the element with the highest priority in the queue,
   *  and removes this element from the queue.
   *
   *  @return   the element with the highest priority.
   */
  override def dequeue(): A = self.dequeue()

  /** Returns the element with the highest priority in the queue,
   *  or throws an error if there is no element contained in the queue.
   *
   *  @return   the element with the highest priority.
   */
  override def head: A = self.head

  /** Removes all elements from the queue. After this operation is completed,
   *  the queue will be empty.
   */
  override def clear(): Unit = self.clear()

  /** Returns a regular queue containing the same elements.
   */
  override def toQueue: Queue[A] = self.toQueue

  /** This method clones the priority queue.
   *
   *  @return  a priority queue with the same elements.
   */
  override def clone(): PriorityQueue[A] = new PriorityQueueProxy[A] {
    def self = PriorityQueueProxy.this.self.clone()
  }
}