public void updateFavoredNodesMap(RegionInfo region, List<ServerName> servers) {
    if (region == null || servers == null || servers.isEmpty()) {
      return;
    }
    this.favoredNodesMap.put(region.getRegionNameAsString(), servers);
  }
Update an assignment to the plan
hbase-balancer/src/main/java/org/apache/hadoop/hbase/favored/FavoredNodesPlan.java