cz.cuni.amis.pathfinding.alg.astar
Class AStarResult<NODE>

java.lang.Object
  cz.cuni.amis.pathfinding.alg.astar.AStarResult<NODE>

All Implemented Interfaces:

IAStarResult<NODE>

public class AStarResult<NODE>
extends Object
implements IAStarResult<NODE>

Represents result of the computation of AStar#AStar.findPath(cz.cuni.amis.pathfinding.map.IPFGoal, long).

It contains results from the search as well as method for finding the path from the startNode to the goalNode.

It contains all data structures the AStar is using during the work. Everything is made public here so that AStar (during work) and you (for browsing the results) may use it.

Field Summary

Set<NODE>	closeList Nodes which were examined by the algorithm.
HashMap<NODE,Integer>	estimatedCost Used and filled by A* algorithm (AStar.aStar()).
NODE	goalNode Node which was marked as a goalNode by AStarMap.
long	interations Contains the number of iterations made by A* search.
cz.cuni.amis.utils.heap.Heap<NODE>	openList List of nodes which is opened -> was touched by the algorithm and are subjects of examination.
HashMap<NODE,Integer>	pathCost Used and filled by A* algorithm (AStar.aStar()).
HashMap<NODE,NODE>	previousNode Used by getPath() and filled by A* algorithm (AStar.aStar()).
NODE	startNode Start node of the A*.
boolean	success Whether goalNode was found during the A* run.

Constructor Summary

AStarResult()

Method Summary

int	getCostToNode(NODE node) Returns cost of the path from startNode to node if the node was touched by A* algorithm (if A* was successful, then this always contains the goalNode and every node on the path at least).
int	getDistanceToGoal() If the AStar succeeded then it returns the distance to the goal from the start node.
int	getEstimatedCostToNode(NODE node) Returns estimated cost of the path from startNode to goal through node.
List<NODE>	getPath() Returns the path from startNode to goalNode.
NODE	getPreviousNode(NODE node) Previous node in the path to the goal node.
boolean	isSuccess() Whether this result represents the success, i.e., path from start to goal node has been found.
void	putCostToNode(NODE node, Integer cost) Assing cost of the path from startNode to node.
void	putEstimatedCostToNode(NODE node, Integer cost) Assing estimated cost of the path from startNode to goalNode through node.
void	putPreviousNode(NODE node, NODE previous) Assing 'previous' as an previous node for 'node' (the path from 'startNode' to 'node' goes across 'previous').

Methods inherited from class java.lang.Object

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

Field Detail

previousNode

public HashMap<NODE,NODE> previousNode

Used by getPath() and filled by A* algorithm (AStar.aStar()). Keys are nodes and values are 'parent-nodes' (from where we've come to the key node on the path from startNode to key-node).

openList

public cz.cuni.amis.utils.heap.Heap<NODE> openList

List of nodes which is opened -> was touched by the algorithm and are subjects of examination. Initialized by AStar.aStar()

closeList

public Set<NODE> closeList

Nodes which were examined by the algorithm. At the end of work of AStar contains all the nodes which were examined. If AStar successful -> at least contains nodes on the shortest path from startNode to goalNode.

pathCost

public HashMap<NODE,Integer> pathCost

Used and filled by A* algorithm (AStar.aStar()). Here we store the real cost from the startNode to the 'key'.

estimatedCost

public HashMap<NODE,Integer> estimatedCost

Used and filled by A* algorithm (AStar.aStar()). Here we store estimated cost of the path from 'key' to the goal.

interations

public long interations

Contains the number of iterations made by A* search. One iteration means evaluating of the one node ("touching" each of the neighbours) Is 0-based ... if startGoal == goalNode or startGoal then this will be 0.

startNode

public NODE startNode

Start node of the A*.

goalNode

public NODE goalNode

Node which was marked as a goalNode by AStarMap. (Note that you theoreticaly may have many goal nodes but A* searches only for the first one.) It's filled only if A* found the goalNoda! (success == true)

success

public boolean success

Whether goalNode was found during the A* run. If this is true then goalNode is not null.

Constructor Detail

AStarResult

public AStarResult()

Method Detail

getPreviousNode

public NODE getPreviousNode(NODE node)

Description copied from interface: IAStarResult

Previous node in the path to the goal node.

Specified by:

getPreviousNode in interface IAStarResult<NODE>

Returns:

previous node of supplied node | null

putPreviousNode

public void putPreviousNode(NODE node,
                            NODE previous)

Assing 'previous' as an previous node for 'node' (the path from 'startNode' to 'node' goes across 'previous').

Parameters:

node -

previous -

getCostToNode

public int getCostToNode(NODE node)

Description copied from interface: IAStarResult

Returns cost of the path from startNode to node if the node was touched by A* algorithm (if A* was successful, then this always contains the goalNode and every node on the path at least).

If node wasn't touched by A* algorithm, then it returns -1.

Specified by:

getCostToNode in interface IAStarResult<NODE>

Returns:

cost of the path from startNode to node

putCostToNode

public void putCostToNode(NODE node,
                          Integer cost)

Assing cost of the path from startNode to node.

Parameters:

node -

cost -

getEstimatedCostToNode

public int getEstimatedCostToNode(NODE node)

Description copied from interface: IAStarResult

Returns estimated cost of the path from startNode to goal through node. If the node was touched by A* algorithm then it has this value stored here (if A* was successful, then this always contains the goalNode and every node on the path at least).

If node wasn't touched by A* algorithm, then it returns -1.

Specified by:

getEstimatedCostToNode in interface IAStarResult<NODE>

Returns:

cost of the path from startNode to node

putEstimatedCostToNode

public void putEstimatedCostToNode(NODE node,
                                   Integer cost)

Assing estimated cost of the path from startNode to goalNode through node.

Parameters:

node -

cost -

getPath

public List<NODE> getPath()

Description copied from interface: IAStarResult

Returns the path from startNode to goalNode. (Don't change it as it's cached, if you want to alter it - then copy it :-)

First item is startNode and the last item is goalNode. If startNode == goalNode then it contains only one item. For each index ... path[index] has neighbor path[index+1].

If the path doesn't exist - returns null.

Specified by:

getPath in interface IAStarResult<NODE>

Returns:

path

getDistanceToGoal

public int getDistanceToGoal()

Description copied from interface: IAStarResult

If the AStar succeeded then it returns the distance to the goal from the start node.

Returns -1 otherwise.

Specified by:

getDistanceToGoal in interface IAStarResult<NODE>

Returns:

distance | -1

isSuccess

public boolean isSuccess()

Description copied from interface: IAStarResult

Whether this result represents the success, i.e., path from start to goal node has been found.

Specified by:

isSuccess in interface IAStarResult<NODE>

Returns: