Package games.stendhal.server.core.pathfinder

Class Pathfinder

java.lang.Object

games.stendhal.server.core.pathfinder.Pathfinder

Direct Known Subclasses:

SimplePathfinder

public abstract class Pathfinder
extends Object

Implements the A* algorithm. Pathing can be done on any class that implements the Navigable interface. See org.generation5.ai.Navigable.

Author:

James Matthews

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	Pathfinder.TreeNode	The pathfinder node.

Field Summary

Fields

Modifier and Type	Field	Description
protected Pathfinder.TreeNode	goalNode	The goal node.
static int	IN_PROGRESS	Returned by getStatus if the pathfinder is still running.
static int	PATH_FOUND	Returned by getStatus if a path has been found.
static int	PATH_NOT_FOUND	Returned by getStatus if a path cannot be found.
protected Pathfinder.TreeNode	startNode	The start node.
protected static double	STRAIGHT_PATH_PREFERENCE_FACTOR	Node weight bonus for nodes that do not change the walking direction.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Pathfinder(int startX, int startY, Rectangle2D destination, double maxDist)

Method Summary

Modifier and Type	Method	Description
abstract Pathfinder.TreeNode	createNode(int x, int y)	Create a new TreeNode
List<Node>	getPath()
protected int	getStatus()	Return the current status of the pathfinder.
protected void	init()	Initialization that can not be done safely in the constructor.
protected boolean	unreachableGoal()	Checks if the goal is unreachable.

Methods inherited from class java.lang.Object

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

Field Details

PATH_NOT_FOUND

public static final int PATH_NOT_FOUND

Returned by getStatus if a path cannot be found.

See Also:

getStatus(), Constant Field Values

PATH_FOUND

public static final int PATH_FOUND

Returned by getStatus if a path has been found.

See Also:

getStatus(), Constant Field Values

IN_PROGRESS

public static final int IN_PROGRESS

Returned by getStatus if the pathfinder is still running.

See Also:

getStatus(), Constant Field Values

STRAIGHT_PATH_PREFERENCE_FACTOR

protected static final double STRAIGHT_PATH_PREFERENCE_FACTOR

Node weight bonus for nodes that do not change the walking direction.

See Also:

Constant Field Values

goalNode

protected Pathfinder.TreeNode goalNode

The goal node.

startNode

protected Pathfinder.TreeNode startNode

The start node.

Constructor Details

Pathfinder

protected Pathfinder(int startX,
 int startY,
 Rectangle2D destination,
 double maxDist)

Method Details

init

protected void init()

Initialization that can not be done safely in the constructor.

getStatus

protected int getStatus()

Return the current status of the pathfinder.

Returns:

the pathfinder status.

See Also:

pathStatus

getPath

public final List<Node> getPath()

unreachableGoal

protected boolean unreachableGoal()

Checks if the goal is unreachable. Only the outer nodes of the goal are checked. There could be other reasons, why a goal is unreachable.

Returns:

true checks if the goal is unreachable

createNode

public abstract Pathfinder.TreeNode createNode(int x,
 int y)

Create a new TreeNode

Parameters:

x - x coordinate of the node

y - y coordinate of the node

Returns:

TreeNode