org.rosuda.util
Class Node

java.lang.Object
  org.rosuda.util.Node

Direct Known Subclasses:

SNode

public class Node
extends Object

Implements the tree structure consisting of cascaded (unmarked) nodes. Each instance of Node represents a node.

Version:

$Id: Node.java,v 1.3 2003/07/30 23:03:47 starsoft Exp $

Field Summary

protected Vector	ch List of all child nodes (all of object type Node)
protected int	height Height of the tree downwards (i.e. assuming this node is the root).
protected int	level Depth (level) of this node.
protected Node	par Parent node

Constructor Summary

Node()
constructs an empty, lonely node

Node(Node t)
constructs a new root node as the parent of a subtree

Method Summary

void	add(Node n) adds a subtree as a child
Node	at(int pos) returns the subnode (child) at specified index
Enumeration	children() returns children enumeration
int	count() returns # of children
void	getAllNodes(Vector dstv) fills specified vector with all nodes contained in the tree (from this node downward, including) in prefix order (i.e. this node is stored as first)
Node[]	getChildren() returns a list of all children
int	getHeight() returns the height of the tree from this node downwards
int	getLevel() returns the level of this node (i.e. the distance from the root)
void	getNodesAtLevel(int dest, Vector nodes) fills provided vector with all nodes at specified level (works downwards only, so makes sense basically only if used with roots) *experimental*
int	getNumNodes(boolean leavesOnly) returns # of nodes in the tree from this node downwards (incl. current one).
Node	getParent() returns parent node
Node	getRoot() returns root if the tree
boolean	isLeaf() checks whether this node is a leaf
boolean	isRoot() checks whether this node is a root
void	prune() prune this node from its parent.
void	rebuildHeight() rebuilds tree height cache for this node and upwards (is called internally after updates.
void	rebuildLevels() rebuilds levels cache for this node and all subnodes (is called internally after updates.
void	remove(Node l) remove a node from current children.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ch

protected Vector ch

List of all child nodes (all of object type Node)

par

protected Node par

Parent node

level

protected int level

Depth (level) of this node. Root has a depth of 0 (cached value)

height

protected int height

Height of the tree downwards (i.e. assuming this node is the root). A single node has the height of 0

Constructor Detail

Node

public Node()

constructs an empty, lonely node

Node

public Node(Node t)

constructs a new root node as the parent of a subtree

Parameters:

t - subtree

Method Detail

isLeaf

public boolean isLeaf()

checks whether this node is a leaf

Returns:

true if this node is a leaf (i.e. has no children)

isRoot

public boolean isRoot()

checks whether this node is a root

Returns:

true if this node is a root (i.e. has no parent)

getChildren

public Node[] getChildren()

returns a list of all children

Returns:

an array of all children (as Node objects or null if this node is a leaf

count

public int count()

returns # of children

Returns:

# of children (or 0 if this node is a leaf)

at

public Node at(int pos)

returns the subnode (child) at specified index

Parameters:

pos - index of the subnode (child). First child is at index 0, last at count()-1. Returns null if range is invalid or node has no children.

Returns:

subnode as Node object

add

public void add(Node n)

adds a subtree as a child

Parameters:

n - node (root of the subtree) to be added

prune

public void prune()

prune this node from its parent. As a result this node becomes a root and the parent loses one child. The method does nothing if this node is already a root.

remove

public void remove(Node l)

remove a node from current children.

Parameters:

l - child to be removed

children

public Enumeration children()

returns children enumeration

Returns:

Enumeration of children of null if leaf.

getParent

public Node getParent()

returns parent node

Returns:

paret node (or null if this node is a root)

getNodesAtLevel

public void getNodesAtLevel(int dest,
                            Vector nodes)

fills provided vector with all nodes at specified level (works downwards only, so makes sense basically only if used with roots) *experimental*

Parameters:

dest - level of nodes to be added

nodes - Vector to be used for storage of the nodes (as Node objects). This method does no sanity checks, so ensure your vector is valid

getRoot

public Node getRoot()

returns root if the tree

Returns:

root of the tree (equals to this if the node is already the root)

getLevel

public int getLevel()

returns the level of this node (i.e. the distance from the root)

Returns:

level of this node (0 for root)

getHeight

public int getHeight()

returns the height of the tree from this node downwards

Returns:

tree height (0 for a leaf)

getAllNodes

public void getAllNodes(Vector dstv)

fills specified vector with all nodes contained in the tree (from this node downward, including) in prefix order (i.e. this node is stored as first)

Parameters:

dstv - destination vector. Objects of type Node are stored. It's not cleared implicitely. Expect a null-exception if you pass null instead of a valid vector.

getNumNodes

public int getNumNodes(boolean leavesOnly)

returns # of nodes in the tree from this node downwards (incl. current one).

Parameters:

leavesOnly - if set to true, only leaves are counted.

Returns:

# of nodes

rebuildLevels

public void rebuildLevels()

rebuilds levels cache for this node and all subnodes (is called internally after updates. There should be no need to call this method externally)

rebuildHeight

public void rebuildHeight()

rebuilds tree height cache for this node and upwards (is called internally after updates. There should be no need to call this method externally)