private Map<byte[], ? extends Collection<byte[]>> makeFamilyMap(byte[] family, byte[] qualifier) {
    if (family == null) {
      return null;
    }

    Map<byte[], Collection<byte[]>> familyMap = new TreeMap<>(Bytes.BYTES_COMPARATOR);
    familyMap.put(family, qualifier != null ? ImmutableSet.of(qualifier) : null);
    return familyMap;
  }
Check the current user for authorization to perform a specific action against the given set of
row data.
<p>
Note: Ordering of the authorization checks has been carefully optimized to short-circuit the
most common requests and minimize the amount of processing required.
</p>
@param request     User request
@param user        User name
@param permRequest the action being requested
@param tableName   Table name
@param families    the map of column families to qualifiers present in the request
@return an authorization result
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AccessChecker.java