ch.sahits.game.openpatrician.engine.sea

Class AStarHeuristicProvider

java.lang.Object

ch.sahits.game.openpatrician.engine.sea.BaseGraphCalulationService

ch.sahits.game.openpatrician.engine.sea.AStarHeuristicProvider

All Implemented Interfaces:

MapGrid

@Component
 @Lazy
public class AStarHeuristicProvider
extends BaseGraphCalulationService

This singleton provides the heuristic for a specific map for the A* algorithm. Initially the heuristic from all nodes to all cities is calculated, based on:

• The Eucledian distance

The heuristic can also be queried if a source has it's heuristic calculated and calculate the heuristic values for that node. The heuristic may not be admissable, meaning that the value given in the heuristic for the distance between A and B may be larger than the actual distance, however the result should still be good enough.

Author:

Andi Hotz, (c) Sahits GmbH, 2015 Created on Dec 31, 2015

Field Summary

Fields

Modifier and Type	Field and Description
private com.google.common.eventbus.AsyncEventBus	clientServerEventBus
private int	height
private Map<javafx.geometry.Point2D,Map<javafx.geometry.Point2D,Double>>	heuristicMap A map of heuristic from a node to each other node in the graph.
private Object	lock
private org.apache.logging.log4j.Logger	logger
private ExecutorService	serverThreadPool
private int	width

Fields inherited from class ch.sahits.game.openpatrician.engine.sea.BaseGraphCalulationService

imageService, map, pointInterner

Fields inherited from interface ch.sahits.game.graphic.image.model.MapGrid

CHECK_DISTANCE, DIAG_CHECK_DISTANCE

Constructor Summary

Constructors

Constructor and Description
AStarHeuristicProvider()

Method Summary

Modifier and Type	Method and Description
void	addSourceNodeToHeuristic(javafx.geometry.Point2D source) Add a new target node to the heuristic.
void	addTargetNodeToHeuristic(javafx.geometry.Point2D target) Add a new target node to the heuristic.
private Map<javafx.geometry.Point2D,Double>	calculateHeuristicForSource(javafx.geometry.Point2D source, List<ch.sahits.game.openpatrician.model.city.ICity> cities)
protected double	calculateWeight(javafx.geometry.Point2D from, javafx.geometry.Point2D to) Calculate the weight between two nodes.
(package private) void	createGraph()
javafx.geometry.Point2D	findClosest(javafx.geometry.Point2D point) Find the closest point in the graph for a defined point.
Map<javafx.geometry.Point2D,Map<javafx.geometry.Point2D,Double>>	getHeuristic() Retrieve the heuristic map.
boolean	heuristicForSourceAvailable(javafx.geometry.Point2D source) Check if the heuristic for a target location is calculated.
private void	initialize()
(package private) void	initImage()

Methods inherited from class ch.sahits.game.openpatrician.engine.sea.BaseGraphCalulationService

getPoint, getSegments, getTangentialSegments, isOnSea

Methods inherited from class java.lang.Object

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

Field Detail

logger

private final org.apache.logging.log4j.Logger logger

serverThreadPool

@Autowired
 @Qualifier(value="serverThreadPool")
private ExecutorService serverThreadPool

clientServerEventBus

@Autowired
 @Qualifier(value="serverClientEventBus")
private com.google.common.eventbus.AsyncEventBus clientServerEventBus

lock

private final Object lock

heuristicMap

private final Map<javafx.geometry.Point2D,Map<javafx.geometry.Point2D,Double>> heuristicMap

A map of heuristic from a node to each other node in the graph. Key of the map is the source and the value is a map of the various destinations and their weight from the source (outer key) to the destination (inner key)

width

private int width

height

private int height

Constructor Detail

AStarHeuristicProvider

public AStarHeuristicProvider()

Method Detail

initialize

@PostConstruct
private void initialize()

initImage

void initImage()
        throws IOException

Throws:

IOException

createGraph

void createGraph()

calculateHeuristicForSource

private Map<javafx.geometry.Point2D,Double> calculateHeuristicForSource(javafx.geometry.Point2D source,
                                                                        List<ch.sahits.game.openpatrician.model.city.ICity> cities)

calculateWeight

protected double calculateWeight(javafx.geometry.Point2D from,
                                 javafx.geometry.Point2D to)

Description copied from class: BaseGraphCalulationService

Calculate the weight between two nodes.

Specified by:

calculateWeight in class BaseGraphCalulationService

Parameters:

from - source node

to - destination node

Returns:

weight of the edge from node from to to

heuristicForSourceAvailable

public boolean heuristicForSourceAvailable(javafx.geometry.Point2D source)

Check if the heuristic for a target location is calculated.

Parameters:

source - location

Returns:

true if the heuristic is present.

getHeuristic

public Map<javafx.geometry.Point2D,Map<javafx.geometry.Point2D,Double>> getHeuristic()

Retrieve the heuristic map. This method is blocking while the heuristic is beeing calculated to ensure there are no out of date data contained.

Returns:

Heuristic map for target locations to any location in the grid.

addTargetNodeToHeuristic

public void addTargetNodeToHeuristic(javafx.geometry.Point2D target)

Add a new target node to the heuristic.

Parameters:

target - location to be added.

addSourceNodeToHeuristic

public void addSourceNodeToHeuristic(javafx.geometry.Point2D source)

Add a new target node to the heuristic.

Parameters:

source - location to be added.

findClosest

public javafx.geometry.Point2D findClosest(javafx.geometry.Point2D point)

Find the closest point in the graph for a defined point.

Parameters:

point - for which the closest defined point should be looked up.

Returns:

closest point to point