/** @param nodes Nodes. */
    private Queue<ClusterNode> fallbacks(Collection<ClusterNode> nodes) {
      Queue<ClusterNode> fallbacks = new LinkedList<>();

      ClusterNode node = F.first(F.view(nodes, IS_LOC_NODE));

      if (node != null) fallbacks.add(node);

      fallbacks.addAll(node != null ? F.view(nodes, F.not(IS_LOC_NODE)) : nodes);

      return fallbacks;
    }
  /**
   * @param cctx Cache context.
   * @param prj Projection (optional).
   * @return Collection of data nodes in provided projection (if any).
   */
  private static Collection<ClusterNode> nodes(
      final GridCacheContext<?, ?> cctx,
      @Nullable final ClusterGroup prj,
      @Nullable final Integer part) {
    assert cctx != null;

    final AffinityTopologyVersion topVer = cctx.affinity().affinityTopologyVersion();

    Collection<ClusterNode> affNodes = CU.affinityNodes(cctx);

    if (prj == null && part == null) return affNodes;

    final Set<ClusterNode> owners =
        part == null
            ? Collections.<ClusterNode>emptySet()
            : new HashSet<>(cctx.topology().owners(part, topVer));

    return F.view(
        affNodes,
        new P1<ClusterNode>() {
          @Override
          public boolean apply(ClusterNode n) {

            return cctx.discovery().cacheAffinityNode(n, cctx.name())
                && (prj == null || prj.node(n.id()) != null)
                && (part == null || owners.contains(n));
          }
        });
  }