/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2010, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.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
*/
trait Map[A, +B] extends Iterable[(A, B)] with MapLike[A, B, Map[A, B]] {
def empty: Map[A, B] = Map.empty
/** The same map with a given default function */
def withDefault[B1 >: B](d: A => B1): Map[A, B1] = new Map.WithDefault[A, B1](this, d)
/** The same map with a given default value */
def withDefaultValue[B1 >: B](d: B1): Map[A, B1] = new Map.WithDefault[A, B1](this, x => d)
}
/** $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]
class WithDefault[A, +B](underlying: Map[A, B], d: A => B) extends Map[A, B] {
override def size = underlying.size
def get(key: A) = underlying.get(key) orElse Some(default(key))
def iterator = underlying.iterator
override def empty = new WithDefault(underlying.empty, d)
override def updated[B1 >: B](key: A, value: B1): WithDefault[A, B1] = new WithDefault[A, B1](underlying.updated[B1](key, value), d)
override def + [B1 >: B](kv: (A, B1)): WithDefault[A, B1] = updated(kv._1, kv._2)
def - (key: A): WithDefault[A, B] = new WithDefault(underlying - key, d)
override def default(key: A): B = d(key)
}
}
