import org.apache.hadoop.ha.proto.HAServiceProtocolProtos.HARequestSource; //导入依赖的package包/类
private HAStateChangeRequestInfoProto convert(StateChangeRequestInfo reqInfo) {
  HARequestSource src;
  switch (reqInfo.getSource()) {
  case REQUEST_BY_USER:
    src = HARequestSource.REQUEST_BY_USER;
    break;
  case REQUEST_BY_USER_FORCED:
    src = HARequestSource.REQUEST_BY_USER_FORCED;
    break;
  case REQUEST_BY_ZKFC:
    src = HARequestSource.REQUEST_BY_ZKFC;
    break;
  default:
    throw new IllegalArgumentException("Bad source: " + reqInfo.getSource());
  }
  return HAStateChangeRequestInfoProto.newBuilder()
      .setReqSource(src)
      .build();
}