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 java.lang.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).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	LowestCommonAncestorFinder.Factory<N,E> An abstraction for LowestCommonAncestorFinder::new.

Constructor Summary

Constructors

Constructor and Description
LowestCommonAncestorFinder(DiGraph<N,E> graph)

Method Summary

Modifier and Type	Method and Description
com.google.common.collect.ImmutableSet<N>	findAll(java.util.Set<N> roots) Execute a search on all the elements of roots.

Methods inherited from class java.lang.Object

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

Constructor Detail

LowestCommonAncestorFinder

public LowestCommonAncestorFinder(DiGraph<N,E> graph)

Method Detail

findAll

public com.google.common.collect.ImmutableSet<N> findAll(java.util.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.