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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2007, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection.mutable
import Predef._
/** This class implements mutable maps using a hashtable.
*
* @author Matthias Zenger
* @author Martin Odersky
* @version 2.0, 31/12/2006
*/
object LinkedHashMap {
/** The empty map of this type */
def empty[A, B] = new LinkedHashMap[A, B]
/** The canonical factory for this type
*/
def apply[A, B](elems: (A, B)*) = empty[A, B] ++ elems
}
@serializable
class LinkedHashMap[A, B] extends Map[A,B] with HashTable[A] with DefaultMapModel[A,B] {
private var ordered = List[Entry]()
def remove(key: A): Option[B] = removeEntry(key) match {
case None => None
case Some(e) =>
ordered = ordered.filter(_ ne e)
Some(e.value)
}
def -= (key: A) { remove(key) }
override def put(key: A, value: B): Option[B] = {
val e = findEntry(key)
if (e == null) {
val e = new Entry(key, value)
ordered = e :: ordered
addEntry(e)
None
} else {
val ret = Some(e.value)
e.value = value
ret
}
}
override def update(key: A, value: B) { put(key, value) }
override def clear() {
ordered = Nil
super.clear()
}
override def clone(): Map[A, B] = new LinkedHashMap[A, B] ++ this
override def elements = ordered.reverse.elements map {e => (e.key, e.value)}
}
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