public Map<ServerName, List<RegionInfo>>
    getSnapShotOfAssignment(final Collection<RegionInfo> regions) {
    final Map<ServerName, List<RegionInfo>> result = new HashMap<ServerName, List<RegionInfo>>();
    if (regions != null) {
      for (RegionInfo hri : regions) {
        final RegionStateNode node = getRegionStateNode(hri);
        if (node == null) {
          continue;
        }
        createSnapshot(node, result);
      }
    } else {
      for (RegionStateNode node : regionsMap.values()) {
        if (node == null) {
          continue;
        }
        createSnapshot(node, result);
      }
    }
    return result;
  }
Returns True if region is offline (In OFFLINE or CLOSED state).
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStates.java