UndirectedMultiNetworkConnections.java 文件源码

private Multiset<N> adjacentNodesMultiset() {
  Multiset<N> adjacentNodes = getReference(adjacentNodesReference);
  if (adjacentNodes == null) {
    adjacentNodes = HashMultiset.create(incidentEdgeMap.values());
    adjacentNodesReference = new SoftReference<Multiset<N>>(adjacentNodes);
  }
  return adjacentNodes;
}