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 testConvertNamenodeRole() {
    assertEquals(NamenodeRoleProto.BACKUP,
        PBHelper.convert(NamenodeRole.BACKUP));
    assertEquals(NamenodeRoleProto.CHECKPOINT,
        PBHelper.convert(NamenodeRole.CHECKPOINT));
    assertEquals(NamenodeRoleProto.NAMENODE,
        PBHelper.convert(NamenodeRole.NAMENODE));
    assertEquals(NamenodeRole.BACKUP,
        PBHelper.convert(NamenodeRoleProto.BACKUP));
    assertEquals(NamenodeRole.CHECKPOINT,
        PBHelper.convert(NamenodeRoleProto.CHECKPOINT));
    assertEquals(NamenodeRole.NAMENODE,
        PBHelper.convert(NamenodeRoleProto.NAMENODE));
  }