public static List<UserPermission> getUserNamespacePermissions(Configuration conf,
    String namespace, String user, boolean hasFilterUser) throws IOException {
    return getUserPermissions(conf, Bytes.toBytes(toNamespaceEntry(namespace)), null, null, user,
      hasFilterUser);
  }
Returns the currently granted permissions for a given namespace as the specified user plus
associated permissions.
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/PermissionStorage.java