Class Router

Object

Router

public class Router
extends Object

This class provides a shortestPath method for finding routes between two points on the map. Start by using Dijkstra's, and if your code isn't fast enough for your satisfaction (or the autograder), upgrade your implementation by switching it to A*. Your code will probably not be fast enough to pass the autograder unless you use A*. The difference between A* and Dijkstra's is only a couple of lines of code, and boils down to the priority you use to order your vertices.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Router.NavigationDirection	Class to represent a navigation direction, which consists of 3 attributes: a direction to go, a way, and the distance to travel for.

Constructor Summary

Constructors

Constructor	Description
Router()

Method Summary

Modifier and Type	Method	Description
static List<Router.NavigationDirection>	routeDirections(GraphDB g, List<Long> route)	Create the list of directions corresponding to a route on the graph.
static List<Long>	shortestPath(GraphDB g, double stlon, double stlat, double destlon, double destlat)	Return a List of longs representing the shortest path from the node closest to a start location and the node closest to the destination location.

Methods inherited from class Object

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

Constructor Detail

Router

public Router()

Method Detail

shortestPath

public static List<Long> shortestPath(GraphDB g,
                                      double stlon,
                                      double stlat,
                                      double destlon,
                                      double destlat)

Return a List of longs representing the shortest path from the node closest to a start location and the node closest to the destination location.

Parameters:

g - The graph to use.

stlon - The longitude of the start location.

stlat - The latitude of the start location.

destlon - The longitude of the destination location.

destlat - The latitude of the destination location.

Returns:

A list of node id's in the order visited on the shortest path.

routeDirections

public static List<Router.NavigationDirection> routeDirections(GraphDB g,
                                                               List<Long> route)

Create the list of directions corresponding to a route on the graph.

Parameters:

g - The graph to use.

route - The route to translate into directions. Each element corresponds to a node from the graph in the route.

Returns:

A list of NavigatiionDirection objects corresponding to the input route.