com.sparsity.sparksee.algorithms

Class SinglePairShortestPathBFS

java.lang.Object

com.sparsity.sparksee.algorithms.ShortestPath

com.sparsity.sparksee.algorithms.SinglePairShortestPath

com.sparsity.sparksee.algorithms.SinglePairShortestPathBFS

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class SinglePairShortestPathBFS
extends SinglePairShortestPath

SinglePairShortestPathBFS class.

It solves the single-pair shortest path problem using a BFS-based implementation.

It is a unweighted algorithm, that is it assumes all edges have the same cost.

Check out the 'Algorithms' section in the SPARKSEE User Manual for more details on this.

Author:

Sparsity Technologies http://www.sparsity-technologies.com

Constructor Summary

Constructors

Constructor and Description
SinglePairShortestPathBFS(Session session, long src, long dst) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
void	addAllEdgeTypes(EdgesDirection dir) Allows for traversing all edge types of the graph.
void	addAllNodeTypes() Allows for traversing all node types of the graph.
void	addEdgeType(int type, EdgesDirection dir) Allows for traversing edges of the given type.
void	addNodeType(int type) Allows for traversing nodes of the given type.
void	checkOnlyExistence() Set that only the path existence must be calculated and not the path itself.
void	excludeEdges(Objects edges) Set which edges can't be used.
void	excludeNodes(Objects nodes) Set which nodes can't be used.
boolean	exists() Returns TRUE If a path exists or FALSE otherwise.
double	getCost() Gets the cost of the shortest path.
OIDList	getPathAsEdges() Gets the shortest path between the source node and the destination node as an ordered set of edges.
OIDList	getPathAsNodes() Gets the shortest path between the source node and the destination node as an ordered set of nodes.
void	run() Executes the algorithm.
void	setMaximumHops(int maxhops) Sets the maximum hops restriction.

Methods inherited from class com.sparsity.sparksee.algorithms.ShortestPath

close, isClosed

Methods inherited from class java.lang.Object

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

Constructor Detail

SinglePairShortestPathBFS

public SinglePairShortestPathBFS(Session session,
                                 long src,
                                 long dst)

Creates a new instance.

Parameters:

session - [in] Session to get the graph from and perform traversal.

src - [in] Source node.

dst - [dst] Destination node.

Method Detail

excludeNodes

public void excludeNodes(Objects nodes)

Set which nodes can't be used.

This will replace any previously specified set of excluded nodes. Should only be used to exclude the usage of specific nodes from allowed node types because it's less efficient than not allowing a node type.

Overrides:

excludeNodes in class SinglePairShortestPath

Parameters:

nodes - [in] A set of node identifiers that must be kept intact until the destruction of the class.

getCost

public double getCost()

Gets the cost of the shortest path.

The cost is the number of hops of the shortest path.

Overrides:

getCost in class SinglePairShortestPath

Returns:

The cost of the shortest path.

run

public void run()

Executes the algorithm.

Overrides:

run in class SinglePairShortestPath

addAllEdgeTypes

public void addAllEdgeTypes(EdgesDirection dir)

Allows for traversing all edge types of the graph.

Overrides:

addAllEdgeTypes in class SinglePairShortestPath

Parameters:

dir - [in] Edge direction.

excludeEdges

public void excludeEdges(Objects edges)

Set which edges can't be used.

This will replace any previously specified set of excluded edges. Should only be used to exclude the usage of specific edges from allowed edge types because it's less efficient than not allowing an edge type.

Overrides:

excludeEdges in class SinglePairShortestPath

Parameters:

edges - [in] A set of edge identifiers that must be kept intact until the destruction of the class.

addEdgeType

public void addEdgeType(int type,
                        EdgesDirection dir)

Allows for traversing edges of the given type.

Overrides:

addEdgeType in class SinglePairShortestPath

Parameters:

type - [in] Edge type.

dir - [in] Edge direction.

getPathAsNodes

public OIDList getPathAsNodes()

Gets the shortest path between the source node and the destination node as an ordered set of nodes.

Overrides:

getPathAsNodes in class SinglePairShortestPath

Returns:

Ordered set of node identifiers.

addNodeType

public void addNodeType(int type)

Allows for traversing nodes of the given type.

Overrides:

addNodeType in class SinglePairShortestPath

Parameters:

type - null

exists

public boolean exists()

Returns TRUE If a path exists or FALSE otherwise.

Overrides:

exists in class SinglePairShortestPath

checkOnlyExistence

public void checkOnlyExistence()

Set that only the path existence must be calculated and not the path itself.

That method should improve the performance of the algorithm, but a call to GetPathAsNodes or GetPathAsEdges will generate an exception even if the path exists.

getPathAsEdges

public OIDList getPathAsEdges()

Gets the shortest path between the source node and the destination node as an ordered set of edges.

Overrides:

getPathAsEdges in class SinglePairShortestPath

Returns:

Ordered set of edge identifiers.

setMaximumHops

public void setMaximumHops(int maxhops)

Sets the maximum hops restriction.

All paths longer than the maximum hops restriction will be ignored.

Overrides:

setMaximumHops in class SinglePairShortestPath

Parameters:

maxhops - [in] The maximum hops restriction. It must be positive or zero. Zero, the default value, means unlimited.

addAllNodeTypes

public void addAllNodeTypes()

Allows for traversing all node types of the graph.

Overrides:

addAllNodeTypes in class SinglePairShortestPath