com.graphhopper.isochrone.algorithm

Class ShortestPathTree

java.lang.Object

com.graphhopper.routing.AbstractRoutingAlgorithm

com.graphhopper.isochrone.algorithm.ShortestPathTree

All Implemented Interfaces:

RoutingAlgorithm

public class ShortestPathTree
extends AbstractRoutingAlgorithm

Computes a shortest path tree by a given weighting. Terminates when all shortest paths up to a given travel time, distance, or weight have been explored.

IMPLEMENTATION NOTE: util.PriorityQueue doesn't support efficient removes. We work around this by giving the labels a deleted flag, not remove()ing them, and popping deleted elements off both queues. Note to self/others: If you think this optimization is not needed, please test it with a scenario where updates actually occur a lot, such as using finite, non-zero u-turn costs.

Author:

Peter Karich, Michael Zilske

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ShortestPathTree.IsoLabel

Field Summary

Fields inherited from class com.graphhopper.routing.AbstractRoutingAlgorithm

edgeExplorer, graph, maxVisitedNodes, nodeAccess, traversalMode, weighting

Constructor Summary

Constructors

Constructor and Description
ShortestPathTree(Graph g, Weighting weighting, boolean reverseFlow, TraversalMode traversalMode)

Method Summary

Modifier and Type	Method and Description
Path	calcPath(int from, int to) Calculates the best path between the specified nodes.
protected Path	extractPath() To be overwritten from extending class.
protected boolean	finished() To be overwritten from extending class.
Collection<ShortestPathTree.IsoLabel>	getIsochroneEdges()
String	getName()
int	getVisitedNodes() Returns the visited nodes after searching.
void	search(int from, Consumer<ShortestPathTree.IsoLabel> consumer)
void	setDistanceLimit(double limit) Distance limit in meter
void	setTimeLimit(double limit) Time limit in milliseconds
void	setWeightLimit(double limit)

Methods inherited from class com.graphhopper.routing.AbstractRoutingAlgorithm

accept, calcPaths, checkAlreadyRun, createEmptyPath, isMaxVisitedNodesExceeded, setMaxVisitedNodes, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ShortestPathTree

public ShortestPathTree(Graph g,
                        Weighting weighting,
                        boolean reverseFlow,
                        TraversalMode traversalMode)

Method Detail

calcPath

public Path calcPath(int from,
                     int to)

Description copied from interface: RoutingAlgorithm

Calculates the best path between the specified nodes.

Returns:

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

setTimeLimit

public void setTimeLimit(double limit)

Time limit in milliseconds

setDistanceLimit

public void setDistanceLimit(double limit)

Distance limit in meter

setWeightLimit

public void setWeightLimit(double limit)

search

public void search(int from,
                   Consumer<ShortestPathTree.IsoLabel> consumer)

getIsochroneEdges

public Collection<ShortestPathTree.IsoLabel> getIsochroneEdges()

finished

protected boolean finished()

Description copied from class: AbstractRoutingAlgorithm

To be overwritten from extending class. Should we make this available in RoutingAlgorithm interface?

Specified by:

finished in class AbstractRoutingAlgorithm

Returns:

true if finished.

extractPath

protected Path extractPath()

Description copied from class: AbstractRoutingAlgorithm

To be overwritten from extending class. Should we make this available in RoutingAlgorithm interface?

Specified by:

extractPath in class AbstractRoutingAlgorithm

Returns:

true if finished.

getName

public String getName()

Specified by:

getName in interface RoutingAlgorithm

Overrides:

getName in class AbstractRoutingAlgorithm

Returns:

name of this algorithm

getVisitedNodes

public int getVisitedNodes()

Description copied from interface: RoutingAlgorithm

Returns the visited nodes after searching. Useful for debugging.