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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2009, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection.immutable
import scala.collection.generic._
/** The canonical factory of <a href="TreeMap.html">TreeMap</a>'s. */
object TreeMap extends ImmutableSortedMapFactory[TreeMap] {
def empty[A, B](implicit ord: Ordering[A]) = new TreeMap[A, B]()(ord)
implicit def builderFactory[A, B](implicit ord: Ordering[A]): BuilderFactory[(A, B), TreeMap[A, B], Coll] = new SortedMapBuilderFactory[A, B]
private def make[A, B](s: Int, t: RedBlack[A]#Tree[B])(implicit ord: Ordering[A]) = new TreeMap[A, B](s, t)(ord)
}
/** This class implements immutable maps using a tree.
*
* @author Erik Stenman
* @author Matthias Zenger
* @version 1.1, 03/05/2004
*/
@serializable
class TreeMap[A, +B](override val size: Int, t: RedBlack[A]#Tree[B])(implicit val ordering: Ordering[A])
extends RedBlack[A]
with SortedMap[A, B]
with SortedMapTemplate[A, B, TreeMap[A, B]]
with ImmutableMapTemplate[A, B, TreeMap[A, B]] {
def isSmaller(x: A, y: A) = ordering.lt(x, y)
override protected[this] def newBuilder : Builder[(A, B), TreeMap[A, B]] =
TreeMap.newBuilder[A, B]
def this()(implicit ordering: Ordering[A]) = this(0, null)(ordering)
protected val tree: RedBlack[A]#Tree[B] = if (size == 0) Empty else t
override def rangeImpl(from : Option[A], until : Option[A]): TreeMap[A,B] = {
val ntree = tree.range(from,until)
new TreeMap[A,B](ntree.count, ntree)
}
override def firstKey = t.first
override def lastKey = t.last
override def compare(k0: A, k1: A): Int = ordering.compare(k0, k1)
/** A factory to create empty maps of the same type of keys.
*/
override def empty: TreeMap[A, B] = TreeMap.empty[A, B](ordering)
/** A new TreeMap with the entry added is returned,
* if key is <em>not</em> in the TreeMap, otherwise
* the key is updated with the new entry.
*
* @param key ...
* @param value ...
* @return ...
*/
override def updated [B1 >: B](key: A, value: B1): TreeMap[A, B1] = {
val newsize = if (tree.lookup(key).isEmpty) size + 1 else size
TreeMap.make(newsize, tree.update(key, value))
}
/** Add a key/value pair to this map.
* @param kv the key/value pair
* @return A new map with the new binding added to this map
*/
override def + [B1 >: B] (kv: (A, B1)): TreeMap[A, B1] = updated(kv._1, kv._2)
/** Adds two or more elements to this collection and returns
* either the collection itself (if it is mutable), or a new collection
* with the added elements.
*
* @param elem1 the first element to add.
* @param elem2 the second element to add.
* @param elems the remaining elements to add.
*/
override def + [B1 >: B] (elem1: (A, B1), elem2: (A, B1), elems: (A, B1) *): TreeMap[A, B1] =
this + elem1 + elem2 ++ elems
/** A new TreeMap with the entry added is returned,
* assuming that key is <em>not</em> in the TreeMap.
*/
def insert [B1 >: B](key: A, value: B1): TreeMap[A, B1] = {
assert(tree.lookup(key).isEmpty)
TreeMap.make(size + 1, tree.update(key, value))
}
def - (key:A): TreeMap[A, B] =
if (tree.lookup(key).isEmpty) this
else TreeMap.make(size - 1, tree.delete(key))
/** Check if this map maps <code>key</code> to a value and return the
* value if it exists.
*
* @param key the key of the mapping of interest
* @return the value of the mapping, if it exists
*/
override def get(key: A): Option[B] = tree.lookup(key) match {
case n: NonEmpty[b] => Some(n.value)
case _ => None
}
/** Creates a new iterator over all elements contained in this
* object.
*
* @return the new iterator
*/
def iterator: Iterator[(A, B)] = tree.toStream.iterator
override def toStream: Stream[(A, B)] = tree.toStream
override def foreach[U](f : ((A,B)) => U) = tree foreach { case (x, y) => f(x, y) }
}
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