Package org.jungrapht.visualization.layout.quadtree

Class Node<T>

java.lang.Object

org.jungrapht.visualization.layout.quadtree.Node<T>

public class Node<T>
extends Object

A Node in the BarnesHutOctTree. Has a rectangular dimension and a ForceObject that may be either a graph node or a representation of the combined forces of the child nodes. May have 4 child nodes.

Author:

Tom Nelson

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Node.Builder<T>

Field Summary

Fields

Modifier and Type	Field	Description
protected Rectangle	area
static double	DEFAULT_THETA	threshold value for determining whether to use the forces in an inner node as a summary value, or to descend the quad tree to another inner node or leaf node.
protected ForceObject<T>	forceObject
protected double	theta

Method Summary

Modifier and Type	Method	Description
void	applyForcesTo(ForceObject<T> visitor)	accept a visit from the visitor force object, and add this node's forces to the visitor
static <T> Node.Builder<T>	builder()
void	clear()	remove all child nodes
Rectangle	getArea()
Rectangle	getBounds()
ForceObject<T>	getForceObject()	if this is an inner node, the forceObject represents the combined force and mass of the child nodes.
Node	getNE()
Node	getNW()
Node	getSE()
Node	getSW()
void	insert(ForceObject<T> element)	insert a new ForceObject into the tree.
boolean	isLeaf()
protected void	split()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_THETA

public static final double DEFAULT_THETA

threshold value for determining whether to use the forces in an inner node as a summary value, or to descend the quad tree to another inner node or leaf node. theta should be between 0 and 1, with 0.5 as a commonly selected value. Note that a theta value of 0 will result in no optimization in the BarnesHutOctTree and all force visitors will descend to a leaf node instead of using an inner node summary force vector.

See Also:

Constant Field Values

forceObject

protected ForceObject<T> forceObject

theta

protected double theta

area

protected Rectangle area

Method Detail

builder

public static <T> Node.Builder<T> builder()

getForceObject

public ForceObject<T> getForceObject()

if this is an inner node, the forceObject represents the combined force and mass of the child nodes.

Returns:

the forceObject for this node.

isLeaf

public boolean isLeaf()

Returns:

true if this node has no child nodes, false otherwise

getNW

public Node getNW()

Returns:

the northwest quadrant node

getNE

public Node getNE()

Returns:

the northeast quadrant node

getSE

public Node getSE()

Returns:

the southeast quadrant node

getSW

public Node getSW()

Returns:

the southwest quadrant node

getArea

public Rectangle getArea()

Returns:

the rectangular area of this node

insert

public void insert(ForceObject<T> element)

insert a new ForceObject into the tree. This changes the combinedMass and the forceVector for any Node that it is inserted into

Parameters:

element -

getBounds

public Rectangle getBounds()

Returns:

the rectangular bounds of this node

clear

public void clear()

remove all child nodes

split

protected void split()

applyForcesTo

public void applyForcesTo(ForceObject<T> visitor)

accept a visit from the visitor force object, and add this node's forces to the visitor

Parameters:

visitor - the visitor

toString

public String toString()

Overrides:

toString in class Object