Package com.google.javascript.jscomp.graph

Class LowestCommonAncestorFinder<N,E>

java.lang.Object
com.google.javascript.jscomp.graph.LowestCommonAncestorFinder<N,E>
public class LowestCommonAncestorFinder<N,E> extends Object
Implements a lowest common ancestor search algorithm.

The LCA of a set of nodes is the node that is an ancestor to all of them but is not an ancestor of any other common ancestor. In a non-tree, There may be multiple LCAs for a given set of search nodes.

In a cyclic graph, the LCAs may not be well defined. Within a cycle, all elements are both above and below one another, so there is no uniquely lowest element. If the set of common ancestors is rooted on a cycle, this implementation returns one or more elements of that cycle. Those elements are chosen arbitrarily but deterministically (as long as the underlying graph has deterministic iteration).

  • Constructor Details

    • LowestCommonAncestorFinder

      public LowestCommonAncestorFinder(DiGraph<N,E> graph)

  • Method Details

    • findAll

      public com.google.common.collect.ImmutableSet<N> findAll(Set<N> roots)
      Execute a search on all the elements of roots.

      This is a general-purpose, bare-bones implementation. There are lots of special case optimizations that could be applied.