Scala example source code file (WrappedArrayBuilder.scala)

This example Scala source code file (WrappedArrayBuilder.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, builder, classtag, int, reflection, wrappedarray, wrappedarraybuilder

The WrappedArrayBuilder.scala Scala example source code

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



package scala
package collection
package mutable

import scala.reflect.ClassTag
import scala.runtime.ScalaRunTime._

/** A builder class for arrays.
 *
 *  @tparam A   type of elements that can be added to this builder.
 *  @param tag  class tag for objects of type `A`.
 *
 *  @since 2.8
 */
class WrappedArrayBuilder[A](tag: ClassTag[A]) extends Builder[A, WrappedArray[A]] {

  @deprecated("use tag instead", "2.10.0")
  val manifest: ClassTag[A] = tag

  private var elems: WrappedArray[A] = _
  private var capacity: Int = 0
  private var size: Int = 0

  private def mkArray(size: Int): WrappedArray[A] = {
    val runtimeClass = arrayElementClass(tag)
    val newelems = runtimeClass match {
      case java.lang.Byte.TYPE      => new WrappedArray.ofByte(new Array[Byte](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Short.TYPE     => new WrappedArray.ofShort(new Array[Short](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Character.TYPE => new WrappedArray.ofChar(new Array[Char](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Integer.TYPE   => new WrappedArray.ofInt(new Array[Int](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Long.TYPE      => new WrappedArray.ofLong(new Array[Long](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Float.TYPE     => new WrappedArray.ofFloat(new Array[Float](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Double.TYPE    => new WrappedArray.ofDouble(new Array[Double](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Boolean.TYPE   => new WrappedArray.ofBoolean(new Array[Boolean](size)).asInstanceOf[WrappedArray[A]]
      case java.lang.Void.TYPE      => new WrappedArray.ofUnit(new Array[Unit](size)).asInstanceOf[WrappedArray[A]]
      case _                        => new WrappedArray.ofRef[A with AnyRef](tag.newArray(size).asInstanceOf[Array[A with AnyRef]]).asInstanceOf[WrappedArray[A]]
    }
    if (this.size > 0) Array.copy(elems.array, 0, newelems.array, 0, this.size)
    newelems
  }

  private def resize(size: Int) {
    elems = mkArray(size)
    capacity = size
  }

  override def sizeHint(size: Int) {
    if (capacity < size) resize(size)
  }

  private def ensureSize(size: Int) {
    if (capacity < size) {
      var newsize = if (capacity == 0) 16 else capacity * 2
      while (newsize < size) newsize *= 2
      resize(newsize)
    }
  }

  def +=(elem: A): this.type = {
    ensureSize(size + 1)
    elems(size) = elem
    size += 1
    this
  }

  def clear() {
    size = 0
  }

  def result() = {
    if (capacity != 0 && capacity == size) elems
    else mkArray(size)
  }

  // todo: add ++=
}