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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection
import generic._
/**
* A map from keys of type `A` to values of type `B`.
*
* $mapNote
*
* '''Note:''' If you do not have specific implementations for `add` and `-` in mind,
* you might consider inheriting from `DefaultMap` instead.
*
* '''Note:''' If your additions and mutations return the same kind of map as the map
* you are defining, you should inherit from `MapLike` as well.
*
* @tparam A the type of the keys in this map.
* @tparam B the type of the values associated with keys.
*
* @since 1.0
*/
trait Map[A, +B] extends Iterable[(A, B)] with GenMap[A, B] with MapLike[A, B, Map[A, B]] {
def empty: Map[A, B] = Map.empty
override def seq: Map[A, B] = this
}
/** $factoryInfo
* @define Coll `Map`
* @define coll map
*/
object Map extends MapFactory[Map] {
def empty[A, B]: immutable.Map[A, B] = immutable.Map.empty
/** $mapCanBuildFromInfo */
implicit def canBuildFrom[A, B]: CanBuildFrom[Coll, (A, B), Map[A, B]] = new MapCanBuildFrom[A, B]
/** An abstract shell used by { mutable, immutable }.Map but not by collection.Map
* because of variance issues.
*/
abstract class WithDefault[A, +B](underlying: Map[A, B], d: A => B) extends AbstractMap[A, B] with Map[A, B] with Serializable {
override def size = underlying.size
def get(key: A) = underlying.get(key) // removed in 2.9: orElse Some(default(key))
def iterator = underlying.iterator
override def default(key: A): B = d(key)
}
}
/** Explicit instantiation of the `Map` trait to reduce class file size in subclasses. */
abstract class AbstractMap[A, +B] extends AbstractIterable[(A, B)] with Map[A, B]
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