com.sparsity.dex.algorithms
Class SinglePairShortestPathBFS

java.lang.Object
  extended by com.sparsity.dex.algorithms.ShortestPath
      extended by com.sparsity.dex.algorithms.SinglePairShortestPath
          extended by com.sparsity.dex.algorithms.SinglePairShortestPathBFS
All Implemented Interfaces:
java.io.Closeable

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 DEX User Manual for more details on this.

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

Constructor Summary
SinglePairShortestPathBFS(Session s, long src, long dst)
          Creates a new instance.
 
Method Summary
 void addAllEdgeTypes(EdgesDirection d)
          Allows for traversing all edge types of the graph.
 void addAllNodeTypes()
          Allows for traversing all node types of the graph.
 void addEdgeType(int t, EdgesDirection d)
          Allows for traversing edges of the given type.
 void addNodeType(int t)
          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.dex.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 s,
                                 long src,
                                 long dst)
Creates a new instance.

Parameters:
s - [in] Session to get the graph from and perform traversal.
src - [in] Source node.
dst - [dst] Destination node.
Method Detail

exists

public boolean exists()
Returns TRUE If a path exists or FALSE otherwise.

Overrides:
exists in class SinglePairShortestPath

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.

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.

addEdgeType

public void addEdgeType(int t,
                        EdgesDirection d)
Allows for traversing edges of the given type.

Overrides:
addEdgeType in class SinglePairShortestPath
Parameters:
t - [in] Edge type.
d - [in] Edge direction.

addNodeType

public void addNodeType(int t)
Allows for traversing nodes of the given type.

Overrides:
addNodeType in class SinglePairShortestPath
Parameters:
t - null

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.

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.

addAllNodeTypes

public void addAllNodeTypes()
Allows for traversing all node types of the graph.

Overrides:
addAllNodeTypes in class SinglePairShortestPath

addAllEdgeTypes

public void addAllEdgeTypes(EdgesDirection d)
Allows for traversing all edge types of the graph.

Overrides:
addAllEdgeTypes in class SinglePairShortestPath
Parameters:
d - [in] Edge direction.

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.

run

public void run()
Executes the algorithm.

Overrides:
run 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.


setMaximumHops

public void setMaximumHops(int maxhops)
Sets the maximum hops restriction.

All paths longer than the maximum hops restriction will be ignored. m[in] The maximum hops restriction. It must be positive or zero. Zero, the default value, means unlimited.

Overrides:
setMaximumHops in class SinglePairShortestPath
Parameters:
maxhops - null