Package com.graphhopper.routing

Class AStar

java.lang.Object

com.graphhopper.routing.AbstractRoutingAlgorithm

com.graphhopper.routing.AStar

All Implemented Interfaces:

EdgeToEdgeRoutingAlgorithm, RoutingAlgorithm

public class AStar
extends AbstractRoutingAlgorithm
implements EdgeToEdgeRoutingAlgorithm

This class implements the A* algorithm according to http://en.wikipedia.org/wiki/A*_search_algorithm

Different distance calculations can be used via setApproximation.

Author:

Peter Karich

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AStar.AStarEntry

Field Summary

Fields inherited from class com.graphhopper.routing.AbstractRoutingAlgorithm

edgeExplorer, graph, maxVisitedNodes, nodeAccess, timeoutMillis, traversalMode, weighting

Constructor Summary

Constructors

Constructor	Description
AStar(Graph graph, Weighting weighting, TraversalMode tMode)

Method Summary

Modifier and Type	Method	Description
Path	calcPath(int from, int to)	Calculates the best path between the specified nodes.
Path	calcPath(int from, int to, int fromOutEdge, int toInEdge)	like RoutingAlgorithm.calcPath(int, int), but this method also allows to strictly restrict the edge the path will begin with and the edge it will end with.
protected Path	extractPath()
String	getName()
int	getVisitedNodes()	Returns the visited nodes after searching.
protected void	initCollections(int size)
AStar	setApproximation(WeightApproximator approx)
protected void	updateBestPath(EdgeIteratorState edgeState, SPTEntry bestSPTEntry, int traversalId)

Methods inherited from class com.graphhopper.routing.AbstractRoutingAlgorithm

accept, calcPaths, checkAlreadyRun, createEmptyPath, isMaxVisitedNodesExceeded, isTimeoutExceeded, setMaxVisitedNodes, setTimeoutMillis, setupFinishTime, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.graphhopper.routing.RoutingAlgorithm

calcPaths, setMaxVisitedNodes, setTimeoutMillis

Constructor Details

AStar

public AStar(Graph graph,
 Weighting weighting,
 TraversalMode tMode)

Method Details

setApproximation

public AStar setApproximation(WeightApproximator approx)

Parameters:

approx - defines how distance to goal Node is approximated

initCollections

protected void initCollections(int size)

calcPath

public Path calcPath(int from,
 int to)

Description copied from interface: RoutingAlgorithm

Calculates the best path between the specified nodes.

Specified by:

calcPath in interface RoutingAlgorithm

Returns:

the path. Call the method found() to make sure that the path is valid.

calcPath

public Path calcPath(int from,
 int to,
 int fromOutEdge,
 int toInEdge)

Description copied from interface: EdgeToEdgeRoutingAlgorithm

like RoutingAlgorithm.calcPath(int, int), but this method also allows to strictly restrict the edge the path will begin with and the edge it will end with.

Specified by:

calcPath in interface EdgeToEdgeRoutingAlgorithm

fromOutEdge - the edge id of the first edge of the path. using EdgeIterator.ANY_EDGE means not enforcing the first edge of the path

toInEdge - the edge id of the last edge of the path. using EdgeIterator.ANY_EDGE means not enforcing the last edge of the path

extractPath

protected Path extractPath()

getVisitedNodes

public int getVisitedNodes()

Description copied from interface: RoutingAlgorithm

Returns the visited nodes after searching. Useful for debugging.

Specified by:

getVisitedNodes in interface RoutingAlgorithm

updateBestPath

protected void updateBestPath(EdgeIteratorState edgeState,
 SPTEntry bestSPTEntry,
 int traversalId)

getName

public String getName()

Specified by:

getName in interface RoutingAlgorithm

Overrides:

getName in class AbstractRoutingAlgorithm

Returns:

name of this algorithm