org.kynosarges.tektosyne.graph

Class PathNode<T>

java.lang.Object

org.kynosarges.tektosyne.graph.PathNode<T>

Type Parameters:

T - the type of all nodes in the Graph

public final class PathNode<T>
extends java.lang.Object

Provides a node within AStar search paths. Associates a Graph node with various other data required by the AStar pathfinding algorithm.

Field Summary

Fields

Modifier and Type	Field and Description
T	node The Graph node that the PathNode represents.

Method Summary

Modifier and Type	Method and Description
java.util.List<PathNode<T>>	children() Gets all accessible direct neighbors of the current node that were examined during the path search.
double	f() Gets the estimated total cost of the search path.
double	g() Gets the total cost of the search path up to the current node.
double	h() Gets the estimated total cost of the search path from the current node.
PathNode<T>	parent() Gets the parent of the PathNode.

Methods inherited from class java.lang.Object

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

Field Detail

node

public final T node

The Graph node that the PathNode represents. The node of the first PathNode in a search path is the source node, and the node of the last PathNode is the target node, assuming that pathfinding was successful.

Method Detail

children

public java.util.List<PathNode<T>> children()

Gets all accessible direct neighbors of the current node that were examined during the path search. AStar adds elements to the children() collection while expanding the current search path.

Returns:

an unmodifiable List of all accessible direct neighbors of the current node that were examined during the path search

f

public double f()

Gets the estimated total cost of the search path. Returns the estimated total cost of the path from source to target that leads across the current node.

Returns:

the sum of g() and h()

g

public double g()

Gets the total cost of the search path up to the current node. Known quantity that represents the total cost to move from the source node to the current node, along the path defined by the chain of parent() links. Zero if the current node is the source node.

Returns:

the total cost of the search path from source to current node

h

public double h()

Gets the estimated total cost of the search path from the current node. Estimated quantity that represents the total cost to move from the current node to the target node. This estimate is usually obtained by calling Graph.getDistance(T, T). Zero if the current node is the target node.

Returns:

the estimated total cost from current node to target

parent

public PathNode<T> parent()

Gets the parent of the PathNode. Tracing back through the parent() links of all PathNode instances in a search path eventually leads back to the source node.

Returns:

the preceding PathNode in a path that starts at the source node, or null for the source node itself