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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection
package mutable
import generic._
import scala.collection.parallel.mutable.ParHashMap
/** This class implements mutable maps using a hashtable.
*
* @since 1
* @see [[http://docs.scala-lang.org/overviews/collections/concrete-mutable-collection-classes.html#hash_tables "Scala's Collection Library overview"]]
* section on `Hash Tables` for more information.
*
* @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 `mutable.HashMap`
* @define coll mutable hash map
* @define thatinfo the class of the returned collection. In the standard library configuration,
* `That` is always `HashMap[A, B]` if the elements contained in the resulting collection are
* pairs of type `(A, B)`. This is because an implicit of type `CanBuildFrom[HashMap, (A, B), HashMap[A, B]]`
* is defined in object `HashMap`. 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 `HashMap`.
* @define mayNotTerminateInf
* @define willNotTerminateInf
*/
@SerialVersionUID(1L)
class HashMap[A, B] private[collection] (contents: HashTable.Contents[A, DefaultEntry[A, B]])
extends AbstractMap[A, B]
with Map[A, B]
with MapLike[A, B, HashMap[A, B]]
with HashTable[A, DefaultEntry[A, B]]
with CustomParallelizable[(A, B), ParHashMap[A, B]]
with Serializable
{
initWithContents(contents)
type Entry = DefaultEntry[A, B]
override def empty: HashMap[A, B] = HashMap.empty[A, B]
override def clear() { clearTable() }
override def size: Int = tableSize
def this() = this(null)
override def par = new ParHashMap[A, B](hashTableContents)
// contains and apply overridden to avoid option allocations.
override def contains(key: A): Boolean = findEntry(key) != null
override def apply(key: A): B = {
val result = findEntry(key)
if (result eq null) default(key)
else result.value
}
def get(key: A): Option[B] = {
val e = findEntry(key)
if (e eq null) None
else Some(e.value)
}
override def getOrElseUpdate(key: A, defaultValue: => B): B = {
val i = index(elemHashCode(key))
val entry = findEntry(key, i)
if (entry != null) entry.value
else addEntry(createNewEntry(key, defaultValue), i)
}
/* inlined HashTable.findEntry0 to preserve its visibility */
private[this] def findEntry(key: A, h: Int): Entry = {
var e = table(h).asInstanceOf[Entry]
while (notFound(key, e))
e = e.next
e
}
private[this] def notFound(key: A, e: Entry): Boolean = (e != null) && !elemEquals(e.key, key)
/* inlined HashTable.addEntry0 to preserve its visibility */
private[this] def addEntry(e: Entry, h: Int): B = {
if (tableSize >= threshold) addEntry(e)
else addEntry0(e, h)
e.value
}
/* extracted to make addEntry inlinable */
private[this] def addEntry0(e: Entry, h: Int) {
e.next = table(h).asInstanceOf[Entry]
table(h) = e
tableSize += 1
nnSizeMapAdd(h)
}
override def put(key: A, value: B): Option[B] = {
val e = findOrAddEntry(key, value)
if (e eq null) None
else { val v = e.value; e.value = value; Some(v) }
}
override def update(key: A, value: B): Unit = put(key, value)
override def remove(key: A): Option[B] = {
val e = removeEntry(key)
if (e ne null) Some(e.value)
else None
}
def += (kv: (A, B)): this.type = {
val e = findOrAddEntry(kv._1, kv._2)
if (e ne null) e.value = kv._2
this
}
def -=(key: A): this.type = { removeEntry(key); this }
def iterator = entriesIterator map (e => ((e.key, e.value)))
override def foreach[U](f: ((A, B)) => U): Unit = foreachEntry(e => f((e.key, e.value)))
/* Override to avoid tuple allocation in foreach */
override def keySet: scala.collection.Set[A] = new DefaultKeySet {
override def foreach[U](f: A => U) = foreachEntry(e => f(e.key))
}
/* Override to avoid tuple allocation in foreach */
override def values: scala.collection.Iterable[B] = new DefaultValuesIterable {
override def foreach[U](f: B => U) = foreachEntry(e => f(e.value))
}
/* Override to avoid tuple allocation */
override def keysIterator: Iterator[A] = new AbstractIterator[A] {
val iter = entriesIterator
def hasNext = iter.hasNext
def next() = iter.next().key
}
/* Override to avoid tuple allocation */
override def valuesIterator: Iterator[B] = new AbstractIterator[B] {
val iter = entriesIterator
def hasNext = iter.hasNext
def next() = iter.next().value
}
/** Toggles whether a size map is used to track hash map statistics.
*/
def useSizeMap(t: Boolean) = if (t) {
if (!isSizeMapDefined) sizeMapInitAndRebuild()
} else sizeMapDisable()
protected def createNewEntry[B1](key: A, value: B1): Entry = {
new Entry(key, value.asInstanceOf[B])
}
private def writeObject(out: java.io.ObjectOutputStream) {
serializeTo(out, { entry =>
out.writeObject(entry.key)
out.writeObject(entry.value)
})
}
private def readObject(in: java.io.ObjectInputStream) {
init(in, createNewEntry(in.readObject().asInstanceOf[A], in.readObject()))
}
}
/** $factoryInfo
* @define Coll `mutable.HashMap`
* @define coll mutable hash map
*/
object HashMap extends MutableMapFactory[HashMap] {
implicit def canBuildFrom[A, B]: CanBuildFrom[Coll, (A, B), HashMap[A, B]] = new MapCanBuildFrom[A, B]
def empty[A, B]: HashMap[A, B] = new HashMap[A, B]
}
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