import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.NamenodeCommandProto; //导入依赖的package包/类
public static NamenodeCommandProto convert(NamenodeCommand cmd) {
  if (cmd instanceof CheckpointCommand) {
    return NamenodeCommandProto.newBuilder().setAction(cmd.getAction())
        .setType(NamenodeCommandProto.Type.CheckPointCommand)
        .setCheckpointCmd(convert((CheckpointCommand) cmd)).build();
  }
  return NamenodeCommandProto.newBuilder()
      .setType(NamenodeCommandProto.Type.NamenodeCommand)
      .setAction(cmd.getAction()).build();
}
 

import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.NamenodeCommandProto; //导入依赖的package包/类
@Override
public NamenodeCommand startCheckpoint(NamenodeRegistration registration)
    throws IOException {
  StartCheckpointRequestProto req = StartCheckpointRequestProto.newBuilder()
      .setRegistration(PBHelper.convert(registration)).build();
  NamenodeCommandProto cmd;
  try {
    cmd = rpcProxy.startCheckpoint(NULL_CONTROLLER, req).getCommand();
  } catch (ServiceException e) {
    throw ProtobufHelper.getRemoteException(e);
  }
  return PBHelper.convert(cmd);
}
 

import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.NamenodeCommandProto; //导入依赖的package包/类
public static NamenodeCommandProto convert(NamenodeCommand cmd) {
  return NamenodeCommandProto.newBuilder()
      .setType(NamenodeCommandProto.Type.NamenodeCommand)
      .setAction(cmd.getAction()).build();
}