Package org.aksw.jenax.util.traversal

Class NaiveLCAFinder

java.lang.Object
org.aksw.jenax.util.traversal.NaiveLCAFinder
public class NaiveLCAFinder extends Object
Note: The class and method names are aligned with jgrapht's NaiveLCAFinder. The difference is that this class supports specification of a custom successor function for nodes. (And this class only depends on jena's Graph) Naive least common ancestor implementation. Does not perform any indexing or caching. For a given pair of nodes for which to find the lca their respective sets of ancestors are alternately expanded with their parents until there is an overlap or there are no more unseen parents to expand.
Example Usage: 
 Graph graph = model.getGraph();
 GraphSuccessorFunction gsf = GraphSuccessorFunction.create(RDFS.subClassOf.asNode(), true); 
 LeastCommonAncestor alg = new LeastCommonAncestor(graph, gsf);
 Set lcas = alg.getLeastCommonAncestor(XSD.nonNegativeInteger.asNode(), XSD.decimal.asNode());
Author:
raven

  • Field Details

    • graph

      protected org.apache.jena.graph.Graph graph

    • successorFn

      protected GraphSuccessorFunction successorFn

  • Constructor Details

    • NaiveLCAFinder

      public NaiveLCAFinder(org.apache.jena.graph.Graph graph)
      Find LCAs of rdfs:subClassOf as a reasonable default

    • NaiveLCAFinder

      public NaiveLCAFinder(org.apache.jena.graph.Graph graph, GraphSuccessorFunction successorFn)

  • Method Details

    • getLCASet

      public Set<org.apache.jena.graph.Node> getLCASet(org.apache.jena.graph.Node a, org.apache.jena.graph.Node b)
      Get the least common ancestor (lca) of two given nodes w.r.t. a model and a hierarchy property.
      Parameters:
      a -
      b -
      Returns:

    • getLCA

      public org.apache.jena.graph.Node getLCA(org.apache.jena.graph.Node a, org.apache.jena.graph.Node b)
      Returns the only LCA of a and b if it exists, null otherwise. IllegalArgumentException if there are multiple lcas.

    • computeLCA

      public static <T> Set<T> computeLCA(T a, T b, Function<? super T,? extends Stream<? extends T>> getParents)
      Generic core of the algorithm

    • calcOverlap

      public static <T> int calcOverlap(Iterator<? extends T> it, Collection<T> seen, Collection<? extends T> col, Collection<T> out)
      Iterate items in 'it' and add each seen item to 'seen'. For any item that is contained 'col' and that item also to 'out'. Return the number of items added to 'out'.

    • main

      public static void main(String[] args)