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Standard library for the Scala Programming Language
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.collection
package mutable
import generic._
/** A simple mutable map backed by a list.
*
* @tparam A the type of the keys contained in this list map.
* @tparam B the type of the values assigned to keys in this list map.
*
* @define Coll `mutable.ListMap`
* @define coll mutable list map
* @define thatinfo the class of the returned collection. In the standard library configuration,
* `That` is always `ListMap[A, B]` if the elements contained in the resulting collection are
* pairs of type `(A, B)`. This is because an implicit of type `CanBuildFrom[ListMap, (A, B), ListMap[A, B]]`
* is defined in object `ListMap`. Otherwise, `That` resolves to the most specific type that doesn't have
* to contain pairs of type `(A, B)`, which is `Iterable`.
* @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 `ListMap`.
* @define mayNotTerminateInf
* @define willNotTerminateInf
* @define orderDependent
* @define orderDependentFold
*/
class ListMap[A, B]
extends AbstractMap[A, B]
with Map[A, B]
with MapLike[A, B, ListMap[A, B]]
with Serializable {
override def empty = ListMap.empty[A, B]
private var elems: List[(A, B)] = List()
private var siz: Int = 0
def get(key: A): Option[B] = elems find (_._1 == key) map (_._2)
def iterator: Iterator[(A, B)] = elems.iterator
def += (kv: (A, B)) = { elems = remove(kv._1, elems); elems = kv :: elems; siz += 1; this }
def -= (key: A) = { elems = remove(key, elems); this }
private def remove(key: A, elems: List[(A, B)]): List[(A, B)] =
if (elems.isEmpty) elems
else if (elems.head._1 == key) { siz -= 1; elems.tail }
else elems.head :: remove(key, elems.tail)
override def clear() = { elems = List(); siz = 0 }
override def size: Int = siz
}
/** $factoryInfo
* @define Coll `mutable.ListMap`
* @define coll mutable list map
*/
object ListMap extends MutableMapFactory[ListMap] {
implicit def canBuildFrom[A, B]: CanBuildFrom[Coll, (A, B), ListMap[A, B]] = new MapCanBuildFrom[A, B]
def empty[A, B]: ListMap[A, B] = new ListMap[A, B]
}