in scala.collection.immutable
class Tree

[scala.serializable]

abstract class Tree [A, B]
extends java.lang.Object
with scala.ScalaObject
General Balanced Trees - highly efficient functional dictionaries.

An efficient implementation of Prof. Arne Andersson's General Balanced Trees. These have no storage overhead compared to plain unbalanced binary trees, and their performance is in general better than AVL trees.

This implementation does not balance the trees after deletions. Since deletions don't increase the height of a tree, this should be OK in most applications. A balance method is provided for those cases where rebalancing is needed.

The tree consists of entries conatining a key with an order.

When instanciating the tree an order for the keys has to be supplied.

Author:
Erik Stenman, Michel Schinz
Version:
1.1, 2005-01-20
Direct known subclasses:
TreeSet, TreeMap

Constructor Summary
def this ()(view$0: (A) => scala.Ordered[A])



Type Summary
protected type aNode
The type of nodes that the tree is build from.


Def Summary
abstract protected def New (sz: scala.Int, t: scala.collection.immutable.GBTree[A,B]) : Tree.this.This
This abstract method should be defined by a concrete implementation C[T] as something like:
       override def New(sz:Int,t:aNode):This {
         new C[T](order) {
          override def size=sz;
          override protected def tree:aNode=t;
       }
      
The concrete implementation should also override the def of This override type This = C[T];

protected def add (key: A, entry: B) : Tree.this.This
A new tree with the entry added is returned, assuming that key is not in the tree.
def balance : Tree.this.This
Create a new balanced tree from the tree. Might be useful to call after many deletions, since deletion does not rebalance the tree.
protected def deleteAny (key: A) : Tree.this.This
Removes the key from the tree.
protected def entries : scala.Iterator[B]
Gives you an iterator over all elements in the tree. The iterator structure corresponds to the call stack of an in-order traversal. Note: The iterator itself has a state, i.e., it is not functional.
protected def findValue (key: A) : scala.Option[B]
Check if this map maps key to a value and return the value if it exists.
abstract protected def getThis : Tree.this.This

def size : scala.Int
The size of the tree, returns 0 (zero) if the tree is empty.
protected def tree : scala.collection.immutable.GBTree[A,B]
The nodes in the tree.
protected def updateOrAdd (key: A, entry: B) : Tree.this.This
A new tree with the entry added is returned, if key is not in the tree, otherwise the key is updated with the new entry.


Constructor Detail
def this ()(view$0: (A) => scala.Ordered[A])

Type Detail
protected type aNode
The type of nodes that the tree is build from.

Def Detail
abstract protected def New (sz: scala.Int, t: scala.collection.immutable.GBTree[A,B]): Tree.this.This
This abstract method should be defined by a concrete implementation C[T] as something like:
       override def New(sz:Int,t:aNode):This {
         new C[T](order) {
          override def size=sz;
          override protected def tree:aNode=t;
       }
      
The concrete implementation should also override the def of This override type This = C[T];

protected def add (key: A, entry: B): Tree.this.This
A new tree with the entry added is returned, assuming that key is not in the tree.
Parameters:
key - ...
Parameters:
entry - ...
Returns:
...

def balance : Tree.this.This
Create a new balanced tree from the tree. Might be useful to call after many deletions, since deletion does not rebalance the tree.

protected def deleteAny (key: A): Tree.this.This
Removes the key from the tree.
Parameters:
key - ...
Returns:
...

protected def entries : scala.Iterator[B]
Gives you an iterator over all elements in the tree. The iterator structure corresponds to the call stack of an in-order traversal. Note: The iterator itself has a state, i.e., it is not functional.

protected def findValue (key: A): scala.Option[B]
Check if this map maps key to a value and return the value if it exists.
Parameters:
key - the key of the mapping of interest
Returns:
the value of the mapping, if it exists

abstract protected def getThis : Tree.this.This

def size : scala.Int
The size of the tree, returns 0 (zero) if the tree is empty.
Returns:
The number of nodes in the tree as an integer.

protected def tree : scala.collection.immutable.GBTree[A,B]
The nodes in the tree.

protected def updateOrAdd (key: A, entry: B): Tree.this.This
A new tree with the entry added is returned, if key is not in the tree, otherwise the key is updated with the new entry.