scala.collection.mutable.Stack.StackBuilder

class StackBuilder[A] extends Builder[A, Stack[A]]

Value Members From scala.collection.generic.Growable

def ++=(xs: TraversableOnce[A]): StackBuilder.this.type

adds all elements produced by a TraversableOnce to this growable collection.

  • xs
    • the TraversableOnce producing the elements to add.
  • returns
    • the growable collection itself.
  • Definition Classes
    • Growable

(defined at scala.collection.generic.Growable)

def +=(elem1: A, elem2: A, elems: A*): StackBuilder.this.type

adds two or more elements to this growable collection.

  • elem1
    • the first element to add.
  • elem2
    • the second element to add.
  • elems
    • the remaining elements to add.
  • returns
    • the growable collection itself
  • Definition Classes
    • Growable

(defined at scala.collection.generic.Growable)

Value Members From scala.collection.mutable.Builder

def mapResult[NewTo](f: (Stack[A]) ⇒ NewTo): Builder[A, NewTo]

Creates a new builder by applying a transformation function to the results of this builder.

  • NewTo
    • the type of collection returned by f .
  • f
    • the transformation function.
  • returns
    • a new builder which is the same as the current builder except that a transformation function is applied to this builder’s result.
  • Definition Classes
    • Builder
  • Note
    • The original builder should no longer be used after mapResult is called.

(defined at scala.collection.mutable.Builder)

def sizeHint(size: Int): Unit

Gives a hint how many elements are expected to be added when the next result is called. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

  • size
    • the hint how many elements will be added.
  • Definition Classes
    • Builder

(defined at scala.collection.mutable.Builder)

def sizeHint(coll: TraversableLike[_, _]): Unit

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike . Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

  • coll
    • the collection which serves as a hint for the result’s size.
  • Definition Classes
    • Builder

(defined at scala.collection.mutable.Builder)

def sizeHint(coll: TraversableLike[_, _], delta: Int): Unit

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike . Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

  • coll
    • the collection which serves as a hint for the result’s size.
  • delta
    • a correction to add to the coll.size to produce the size hint.
  • Definition Classes
    • Builder

(defined at scala.collection.mutable.Builder)

def sizeHintBounded(size: Int, boundingColl: TraversableLike[_, _]): Unit

Gives a hint how many elements are expected to be added when the next result is called, together with an upper bound given by the size of some other collection. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

  • size
    • the hint how many elements will be added.
  • boundingColl
    • the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection’s size are reduced.
  • Definition Classes
    • Builder

(defined at scala.collection.mutable.Builder)

Instance Constructors From scala.collection.mutable.Stack.StackBuilder

new StackBuilder()

(defined at scala.collection.mutable.Stack.StackBuilder)

Value Members From scala.collection.mutable.Stack.StackBuilder

def +=(elem: A): StackBuilder.this.type

Adds a single element to the builder.

  • elem
    • the element to be added.
  • returns
    • the builder itself.
  • Definition Classes
    • StackBuilder → Builder → Growable

(defined at scala.collection.mutable.Stack.StackBuilder)

val lbuff: ListBuffer[A]

(defined at scala.collection.mutable.Stack.StackBuilder)

def result(): Stack[A]

Produces a collection from the added elements. This is a terminal operation: the builder’s contents are undefined after this operation, and no further methods should be called.

  • returns
    • a collection containing the elements added to this builder.
  • Definition Classes
    • StackBuilder → Builder

(defined at scala.collection.mutable.Stack.StackBuilder)

Value Members From Implicit scala.collection.parallel.CollectionsHaveToParArray ——————————————————————————–

def toParArray: ParArray[T]

  • Implicit information
    • This member is added by an implicit conversion from StackBuilder [A] to CollectionsHaveToParArray [StackBuilder [A], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (StackBuilder [A]) ⇒ GenTraversableOnce [T] is in scope.
  • Definition Classes
    • CollectionsHaveToParArray (added by implicit convertion: scala.collection.parallel.CollectionsHaveToParArray)

Full Source:

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



package scala
package collection
package mutable

import generic._
import scala.collection.immutable.{List, Nil}
import scala.collection.Iterator
import scala.annotation.migration

/** Factory object for the `mutable.Stack` class.
 *
 *  $factoryInfo
 *  @define coll mutable stack
 *  @define Coll `mutable.Stack`
 */
object Stack extends SeqFactory[Stack] {
  class StackBuilder[A] extends Builder[A, Stack[A]] {
    val lbuff = new ListBuffer[A]
    def +=(elem: A) = { lbuff += elem; this }
    def clear() = lbuff.clear()
    def result = new Stack(lbuff.result)
  }

  implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, Stack[A]] = ReusableCBF.asInstanceOf[GenericCanBuildFrom[A]]
  def newBuilder[A]: Builder[A, Stack[A]] = new StackBuilder[A]
  val empty: Stack[Nothing] = new Stack(Nil)
}

/** A stack implements a data structure which allows to store and retrieve
 *  objects in a last-in-first-out (LIFO) fashion.
 *
 *  @tparam A    type of the elements contained in this stack.
 *
 *  @author  Matthias Zenger
 *  @author  Martin Odersky
 *  @version 2.8
 *  @since   1
 *  @see [[http://docs.scala-lang.org/overviews/collections/concrete-mutable-collection-classes.html#stacks "Scala's Collection Library overview"]]
 *  section on `Stacks` for more information.
 *  @define Coll `Stack`
 *  @define coll stack
 *  @define orderDependent
 *  @define orderDependentFold
 *  @define mayNotTerminateInf
 *  @define willNotTerminateInf
 */
class Stack[A] private (var elems: List[A])
extends AbstractSeq[A]
   with Seq[A]
   with SeqLike[A, Stack[A]]
   with GenericTraversableTemplate[A, Stack]
   with Cloneable[Stack[A]]
   with Serializable
{
  def this() = this(Nil)

  override def companion = Stack

  /** Checks if the stack is empty.
   *
   *  @return true, iff there is no element on the stack
   */
  override def isEmpty: Boolean = elems.isEmpty

  /** The number of elements in the stack */
  override def length = elems.length

  /** Retrieve `n`-th element from stack, where top of stack has index `0`.
   *
   *  This is a linear time operation.
   *
   *  @param index     the index of the element to return
   *  @return          the element at the specified index
   *  @throws IndexOutOfBoundsException if the index is out of bounds
   */
  override def apply(index: Int) = elems(index)

  /** Replace element at index `n` with the new element `newelem`.
   *
   *  This is a linear time operation.
   *
   *  @param n       the index of the element to replace.
   *  @param newelem the new element.
   *  @throws   IndexOutOfBoundsException if the index is not valid
   */
  def update(n: Int, newelem: A) =
    if(n < 0 || n >= length) throw new IndexOutOfBoundsException(n.toString)
    else elems = elems.take(n) ++ (newelem :: elems.drop(n+1))

  /** Push an element on the stack.
   *
   *  @param   elem       the element to push on the stack.
   *  @return the stack with the new element on top.
   */
  def push(elem: A): this.type = { elems = elem :: elems; this }

  /** Push two or more elements onto the stack. The last element
   *  of the sequence will be on top of the new stack.
   *
   *  @param   elems      the element sequence.
   *  @return the stack with the new elements on top.
   */
  def push(elem1: A, elem2: A, elems: A*): this.type =
    this.push(elem1).push(elem2).pushAll(elems)

  /** Push all elements in the given traversable object onto the stack. The
   *  last element in the traversable object will be on top of the new stack.
   *
   *  @param xs the traversable object.
   *  @return the stack with the new elements on top.
   */
  def pushAll(xs: TraversableOnce[A]): this.type = { xs foreach push ; this }

  /** Returns the top element of the stack. This method will not remove
   *  the element from the stack. An error is signaled if there is no
   *  element on the stack.
   *
   *  @throws java.util.NoSuchElementException
   *  @return the top element
   */
  def top: A =
    elems.head

  /** Removes the top element from the stack.
   *
   *  @throws java.util.NoSuchElementException
   *  @return the top element
   */
  def pop(): A = {
    val res = elems.head
    elems = elems.tail
    res
  }

  /**
   * Removes all elements from the stack. After this operation completed,
   * the stack will be empty.
   */
  def clear(): Unit = elems = Nil

  /** Returns an iterator over all elements on the stack. This iterator
   *  is stable with respect to state changes in the stack object; i.e.
   *  such changes will not be reflected in the iterator. The iterator
   *  issues elements in the reversed order they were inserted into the
   *  stack (LIFO order).
   *
   *  @return an iterator over all stack elements.
   */
  @migration("`iterator` traverses in FIFO order.", "2.8.0")
  override def iterator: Iterator[A] = elems.iterator

  /** Creates a list of all stack elements in LIFO order.
   *
   *  @return the created list.
   */
  @migration("`toList` traverses in FIFO order.", "2.8.0")
  override def toList: List[A] = elems

  @migration("`foreach` traverses in FIFO order.", "2.8.0")
  override def foreach[U](f: A => U): Unit = super.foreach(f)

  /** This method clones the stack.
   *
   *  @return  a stack with the same elements.
   */
  override def clone(): Stack[A] = new Stack[A](elems)
}