org.apache.hadoop.hdfs.protocol.datatransfer

Class Sender

java.lang.Object

org.apache.hadoop.hdfs.protocol.datatransfer.Sender

All Implemented Interfaces:

DataTransferProtocol

@InterfaceAudience.Private
@InterfaceStability.Evolving
public class Sender
extends Object
implements DataTransferProtocol

Sender

Field Summary

Fields inherited from interface org.apache.hadoop.hdfs.protocol.datatransfer.DataTransferProtocol

DATA_TRANSFER_VERSION, LOG

Constructor Summary

Constructors

Constructor and Description
Sender(DataOutputStream out) Create a sender for DataTransferProtocol with a output stream.

Method Summary

Methods

Modifier and Type	Method and Description
void	blockChecksum(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken) Get block checksum (MD5 of CRC32).
void	copyBlock(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken) Copy a block.
void	readBlock(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken, String clientName, long blockOffset, long length, boolean sendChecksum, CachingStrategy cachingStrategy) Read a block.
void	replaceBlock(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken, String delHint, DatanodeInfo source) Receive a block from a source datanode and then notifies the namenode to remove the copy from the original datanode.
void	requestShortCircuitFds(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken, int maxVersion) Request short circuit access file descriptors from a DataNode.
void	transferBlock(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken, String clientName, DatanodeInfo[] targets) Transfer a block to another datanode.
void	writeBlock(ExtendedBlock blk, Token<BlockTokenIdentifier> blockToken, String clientName, DatanodeInfo[] targets, DatanodeInfo source, BlockConstructionStage stage, int pipelineSize, long minBytesRcvd, long maxBytesRcvd, long latestGenerationStamp, DataChecksum requestedChecksum, CachingStrategy cachingStrategy) Write a block to a datanode pipeline.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Sender

public Sender(DataOutputStream out)

Create a sender for DataTransferProtocol with a output stream.

Method Detail

readBlock

public void readBlock(ExtendedBlock blk,
             Token<BlockTokenIdentifier> blockToken,
             String clientName,
             long blockOffset,
             long length,
             boolean sendChecksum,
             CachingStrategy cachingStrategy)
               throws IOException

Description copied from interface: DataTransferProtocol

Read a block.

Specified by:

readBlock in interface DataTransferProtocol

Parameters:

blk - the block being read.

blockToken - security token for accessing the block.

clientName - client's name.

blockOffset - offset of the block.

length - maximum number of bytes for this read.

sendChecksum - if false, the DN should skip reading and sending checksums

cachingStrategy - The caching strategy to use.

Throws:

IOException

writeBlock

public void writeBlock(ExtendedBlock blk,
              Token<BlockTokenIdentifier> blockToken,
              String clientName,
              DatanodeInfo[] targets,
              DatanodeInfo source,
              BlockConstructionStage stage,
              int pipelineSize,
              long minBytesRcvd,
              long maxBytesRcvd,
              long latestGenerationStamp,
              DataChecksum requestedChecksum,
              CachingStrategy cachingStrategy)
                throws IOException

Description copied from interface: DataTransferProtocol

Write a block to a datanode pipeline.

Specified by:

writeBlock in interface DataTransferProtocol

Parameters:

blk - the block being written.

blockToken - security token for accessing the block.

clientName - client's name.

targets - target datanodes in the pipeline.

source - source datanode.

stage - pipeline stage.

pipelineSize - the size of the pipeline.

minBytesRcvd - minimum number of bytes received.

maxBytesRcvd - maximum number of bytes received.

latestGenerationStamp - the latest generation stamp of the block.

Throws:

IOException

transferBlock

public void transferBlock(ExtendedBlock blk,
                 Token<BlockTokenIdentifier> blockToken,
                 String clientName,
                 DatanodeInfo[] targets)
                   throws IOException

Description copied from interface: DataTransferProtocol

Transfer a block to another datanode. The block stage must be either BlockConstructionStage.TRANSFER_RBW or BlockConstructionStage.TRANSFER_FINALIZED.

Specified by:

transferBlock in interface DataTransferProtocol

Parameters:

blk - the block being transferred.

blockToken - security token for accessing the block.

clientName - client's name.

targets - target datanodes.

Throws:

IOException

requestShortCircuitFds

public void requestShortCircuitFds(ExtendedBlock blk,
                          Token<BlockTokenIdentifier> blockToken,
                          int maxVersion)
                            throws IOException

Description copied from interface: DataTransferProtocol

Request short circuit access file descriptors from a DataNode.

Specified by:

requestShortCircuitFds in interface DataTransferProtocol

Parameters:

blk - The block to get file descriptors for.

blockToken - Security token for accessing the block.

maxVersion - Maximum version of the block data the client can understand.

Throws:

IOException

replaceBlock

public void replaceBlock(ExtendedBlock blk,
                Token<BlockTokenIdentifier> blockToken,
                String delHint,
                DatanodeInfo source)
                  throws IOException

Description copied from interface: DataTransferProtocol

Receive a block from a source datanode and then notifies the namenode to remove the copy from the original datanode. Note that the source datanode and the original datanode can be different. It is used for balancing purpose.

Specified by:

replaceBlock in interface DataTransferProtocol

Parameters:

blk - the block being replaced.

blockToken - security token for accessing the block.

delHint - the hint for deleting the block in the original datanode.

source - the source datanode for receiving the block.

Throws:

IOException

copyBlock

public void copyBlock(ExtendedBlock blk,
             Token<BlockTokenIdentifier> blockToken)
               throws IOException

Description copied from interface: DataTransferProtocol

Copy a block. It is used for balancing purpose.

Specified by:

copyBlock in interface DataTransferProtocol

Parameters:

blk - the block being copied.

blockToken - security token for accessing the block.

Throws:

IOException

blockChecksum

public void blockChecksum(ExtendedBlock blk,
                 Token<BlockTokenIdentifier> blockToken)
                   throws IOException

Description copied from interface: DataTransferProtocol

Get block checksum (MD5 of CRC32).

Specified by:

blockChecksum in interface DataTransferProtocol

Parameters:

blk - a block.

blockToken - security token for accessing the block.

Throws:

IOException