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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2011, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.collection
package mutable
import generic._
/** $factoryInfo
* @define Coll LinkedHashMap
* @define coll linked hash map
*/
object LinkedHashMap extends MutableMapFactory[LinkedHashMap] {
implicit def canBuildFrom[A, B]: CanBuildFrom[Coll, (A, B), LinkedHashMap[A, B]] = new MapCanBuildFrom[A, B]
def empty[A, B] = new LinkedHashMap[A, B]
}
/** This class implements mutable maps using a hashtable.
* The iterator and all traversal methods of this class visit elements in the order they were inserted.
*
* @tparam A the type of the keys contained in this hash map.
* @tparam B the type of the values assigned to keys in this hash map.
*
* @define Coll LinkedHashMap
* @define coll linked hash map
* @define thatinfo the class of the returned collection. In the standard library configuration,
* `That` is always `LinkedHashMap[A, B]` if the elements contained in the resulting collection are
* pairs of type `(A, B)`. This is because an implicit of type `CanBuildFrom[LinkedHashMap, (A, B), LinkedHashMap[A, B]]`
* is defined in object `LinkedHashMap`. 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 `LinkedHashMap`.
* @define mayNotTerminateInf
* @define willNotTerminateInf
* @define orderDependent
* @define orderDependentFold
*/
@SerialVersionUID(1L)
class LinkedHashMap[A, B] extends Map[A, B]
with MapLike[A, B, LinkedHashMap[A, B]]
with HashTable[A, LinkedEntry[A, B]]
with Serializable {
override def empty = LinkedHashMap.empty[A, B]
override def size = tableSize
type Entry = LinkedEntry[A, B]
@transient protected var firstEntry: Entry = null
@transient protected var lastEntry: Entry = null
def get(key: A): Option[B] = {
val e = findEntry(key)
if (e == null) None
else Some(e.value)
}
override def put(key: A, value: B): Option[B] = {
val e = findEntry(key)
if (e == null) {
val e = new Entry(key, value)
addEntry(e)
updateLinkedEntries(e)
None
} else {
val v = e.value
e.value = value
Some(v)
}
}
private def updateLinkedEntries(e: Entry) {
if (firstEntry == null) firstEntry = e
else { lastEntry.later = e; e.earlier = lastEntry }
lastEntry = e
}
override def remove(key: A): Option[B] = {
val e = removeEntry(key)
if (e eq null) None
else {
if (e.earlier eq null) firstEntry = e.later
else e.earlier.later = e.later
if (e.later eq null) lastEntry = e.earlier
else e.later.earlier = e.earlier
Some(e.value)
}
}
def += (kv: (A, B)): this.type = { put(kv._1, kv._2); this }
def -=(key: A): this.type = { remove(key); this }
def iterator: Iterator[(A, B)] = new Iterator[(A, B)] {
private var cur = firstEntry
def hasNext = cur ne null
def next =
if (hasNext) { val res = (cur.key, cur.value); cur = cur.later; res }
else Iterator.empty.next
}
override def keysIterator: Iterator[A] = new Iterator[A] {
private var cur = firstEntry
def hasNext = cur ne null
def next =
if (hasNext) { val res = cur.key; cur = cur.later; res }
else Iterator.empty.next
}
override def valuesIterator: Iterator[B] = new Iterator[B] {
private var cur = firstEntry
def hasNext = cur ne null
def next =
if (hasNext) { val res = cur.value; cur = cur.later; res }
else Iterator.empty.next
}
override def foreach[U](f: ((A, B)) => U) = {
var cur = firstEntry
while (cur ne null) {
f((cur.key, cur.value))
cur = cur.later
}
}
override def clear() {
clearTable()
firstEntry = null
}
private def writeObject(out: java.io.ObjectOutputStream) {
serializeTo(out, _.value)
}
private def readObject(in: java.io.ObjectInputStream) {
firstEntry = null
lastEntry = null
init[B](in, { (key, value) =>
val entry = new Entry(key, value)
updateLinkedEntries(entry)
entry
})
}
}
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