org.apache.hadoop.hdfs.protocol

接口 ClientDatanodeProtocol

所有超级接口:

VersionedProtocol

所有已知实现类:

DataNode

public interface ClientDatanodeProtocol
extends VersionedProtocol

An client-datanode protocol for block recovery

字段概要

字段

限定符和类型	字段和说明
static org.apache.commons.logging.Log	LOG
static long	versionID 4: never return null and always return a newly generated access token

方法概要

方法

限定符和类型	方法和说明
Block	getBlockInfo(Block block) Returns a block object that contains the specified block object from the specified Datanode.
BlockLocalPathInfo	getBlockLocalPathInfo(Block block, Token<BlockTokenIdentifier> token) Retrieves the path names of the block file and metadata file stored on the local file system.
LocatedBlock	recoverBlock(Block block, boolean keepLength, DatanodeInfo[] targets) Start generation-stamp recovery for specified block

从接口继承的方法 org.apache.hadoop.ipc.VersionedProtocol

getProtocolVersion

字段详细资料

LOG

static final org.apache.commons.logging.Log LOG

versionID

static final long versionID

4: never return null and always return a newly generated access token

另请参阅:

常量字段值

方法详细资料

recoverBlock

LocatedBlock recoverBlock(Block block,
                        boolean keepLength,
                        DatanodeInfo[] targets)
                          throws IOException

Start generation-stamp recovery for specified block

参数:

block - the specified block

keepLength - keep the block length

targets - the list of possible locations of specified block

返回:

either a new generation stamp, or the original generation stamp. Regardless of whether a new generation stamp is returned, a newly generated access token is returned as part of the return value.

抛出:

IOException

getBlockInfo

Block getBlockInfo(Block block)
                   throws IOException

Returns a block object that contains the specified block object from the specified Datanode.

参数:

block - the specified block

返回:

the Block object from the specified Datanode

抛出:

IOException - if the block does not exist

getBlockLocalPathInfo

BlockLocalPathInfo getBlockLocalPathInfo(Block block,
                                       Token<BlockTokenIdentifier> token)
                                         throws IOException

Retrieves the path names of the block file and metadata file stored on the local file system. In order for this method to work, one of the following should be satisfied:

• The client user must be configured at the datanode to be able to use this method.
• When security is enabled, kerberos authentication must be used to connect to the datanode.

参数:

block - the specified block on the local datanode

token - the block access token.

返回:

the BlockLocalPathInfo of a block

抛出:

IOException - on error