Class SinglePairShortestPathDijkstra

java.lang.Object
com.sparsity.sparksee.algorithms.ShortestPath
com.sparsity.sparksee.algorithms.SinglePairShortestPath
com.sparsity.sparksee.algorithms.SinglePairShortestPathDijkstra
All Implemented Interfaces:
Closeable, AutoCloseable
public class SinglePairShortestPathDijkstra extends SinglePairShortestPath
SinglePairShortestPathDijkstra class.

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

It is a weighted algorithm, so it takes into account the cost of the edges to compute a minimum-cost shortest path. That is, the user may set for each edge type which attribute should be used to retrieve the cost of the edge. If no attribute is given for an edge type, this will assume the edge has a fixed cost (the default is 1). Only numerical attribute can be set as weight attributes (that is Long, Integer or Double attributes are allowed).

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

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

  • Constructor Details

    • SinglePairShortestPathDijkstra

      public SinglePairShortestPathDijkstra(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 Details

    • 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 sum of the weights of the edges in 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.

    • setUnweightedEdgeCost

      public void setUnweightedEdgeCost(double weight)
      Sets the weight assigned to the unweighted edges.

      All the edges from the types added without an explicit weight attribute will get this weight. The default weight for this edges is 1.

      Parameters:
      weight - [in] The weight value for unweighted edges.

    • 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.

    • setDynamicEdgeCostCallback

      public void setDynamicEdgeCostCallback(SinglePairShortestPathDijkstraDynamicCost dynCostCalculator)
      Set a class callback to dynamically calculate the cost of the edges.

      The callback can be set to NULL (the default) to use the normal attribute based cost weights. The given class must be kept alive by the user for as long as the algorithm is running.

      Parameters:
      dynCostCalculator - [in] Class callback to calculate the edge costs

    • 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

    • 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.

    • addWeightedEdgeType

      public void addWeightedEdgeType(int type, EdgesDirection dir, int attr)
      Allows for traversing edges of the given type using the given attribute as the weight.

      Parameters:
      type - [in] Edge type.
      dir - [in] Edge direction.
      attr - [in] Attribute to be used as the weight. It must be a global attribute or an attribute of the given edge type.

    • 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