public static NamenodeRole convert(NamenodeRoleProto role) {
    switch (role) {
    case NAMENODE:
      return NamenodeRole.NAMENODE;
    case BACKUP:
      return NamenodeRole.BACKUP;
    case CHECKPOINT:
      return NamenodeRole.CHECKPOINT;
    }
    return null;
  }
@Test
  public void testConvertBlockKey() {
    BlockKey key = getBlockKey(1);
    BlockKeyProto keyProto = PBHelper.convert(key);
    BlockKey key1 = PBHelper.convert(keyProto);
    compare(key, key1);
  }