Scala example source code file (HashSet.scala)

This example Scala source code file (HashSet.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, boolean, canbuildfrom, collection, genericcompanion, hashset, iterator, mutable, parallel, parhashset, serializable, serialversionuid, u

The HashSet.scala Scala example source code

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



package scala
package collection
package mutable

import generic._
import scala.collection.parallel.mutable.ParHashSet

/** This class implements mutable sets using a hashtable.
 *
 *  @author  Matthias Zenger
 *  @author  Martin Odersky
 *  @version 2.0, 31/12/2006
 *  @since   1
 *  @see [[http://docs.scala-lang.org/overviews/collections/concrete-mutable-collection-classes.html#hash_tables "Scala's Collection Library overview"]]
 *  section on `Hash Tables` for more information.
 *
 *  @define Coll `mutable.HashSet`
 *  @define coll mutable hash set
 *  @define thatinfo the class of the returned collection. In the standard library configuration,
 *    `That` is always `HashSet[B]` because an implicit of type `CanBuildFrom[HashSet, B, HashSet[B]]`
 *    is defined in object `HashSet`.
 *  @define bfinfo an implicit value of class `CanBuildFrom` which determines the
 *    result class `That` from the current representation type `Repr`
 *    and the new element type `B`. This is usually the `canBuildFrom` value
 *    defined in object `HashSet`.
 *  @define mayNotTerminateInf
 *  @define willNotTerminateInf
 */
@SerialVersionUID(1L)
class HashSet[A] private[collection] (contents: FlatHashTable.Contents[A])
extends AbstractSet[A]
   with Set[A]
   with GenericSetTemplate[A, HashSet]
   with SetLike[A, HashSet[A]]
   with FlatHashTable[A]
   with CustomParallelizable[A, ParHashSet[A]]
   with Serializable
{
  initWithContents(contents)

  def this() = this(null)

  override def companion: GenericCompanion[HashSet] = HashSet

  override def size: Int = tableSize

  def contains(elem: A): Boolean = containsElem(elem)

  def += (elem: A): this.type = { addElem(elem); this }

  def -= (elem: A): this.type = { removeElem(elem); this }

  override def par = new ParHashSet(hashTableContents)

  override def add(elem: A): Boolean = addElem(elem)

  override def remove(elem: A): Boolean = removeElem(elem)

  override def clear() { clearTable() }

  override def iterator: Iterator[A] = super[FlatHashTable].iterator

  override def foreach[U](f: A =>  U) {
    var i = 0
    val len = table.length
    while (i < len) {
      val curEntry = table(i)
      if (curEntry ne null) f(entryToElem(curEntry))
      i += 1
    }
  }

  override def clone() = new HashSet[A] ++= this

  private def writeObject(s: java.io.ObjectOutputStream) {
    serializeTo(s)
  }

  private def readObject(in: java.io.ObjectInputStream) {
    init(in, x => ())
  }

  /** Toggles whether a size map is used to track hash map statistics.
   */
  def useSizeMap(t: Boolean) = if (t) {
    if (!isSizeMapDefined) sizeMapInitAndRebuild()
  } else sizeMapDisable()

}

/** $factoryInfo
 *  @define Coll `mutable.HashSet`
 *  @define coll mutable hash set
 */
object HashSet extends MutableSetFactory[HashSet] {
  implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, HashSet[A]] = setCanBuildFrom[A]
  override def empty[A]: HashSet[A] = new HashSet[A]
}