org.apache.hadoop.hdfs.server.datanode

Class ReplicaInfo

java.lang.Object

org.apache.hadoop.hdfs.protocol.Block

org.apache.hadoop.hdfs.server.datanode.ReplicaInfo

All Implemented Interfaces:

Comparable<Block>, Replica, Writable

Direct Known Subclasses:

FinalizedReplica, ReplicaInPipeline, ReplicaUnderRecovery, ReplicaWaitingToBeRecovered

@InterfaceAudience.Private
public abstract class ReplicaInfo
extends Block
implements Replica

This class is used by datanodes to maintain meta data of its replicas. It provides a general interface for meta information of a replica.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ReplicaInfo.ReplicaDirInfo

Field Summary

Fields inherited from class org.apache.hadoop.hdfs.protocol.Block

BLOCK_FILE_PREFIX, blockFilePattern, METADATA_EXTENSION, metaFilePattern

Method Summary

Methods

Modifier and Type	Method and Description
File	getBlockFile() Get the full path of this replica's data file
File	getMetaFile() Get the full path of this replica's meta file
FsVolumeSpi	getVolume() Get the volume where this replica is located on disk
boolean	isUnlinked() check if this replica has already been unlinked.
static ReplicaInfo.ReplicaDirInfo	parseSubDirs(File dir)
void	setDir(File dir) Set the parent directory where this replica is located
void	setUnlinked() set that this replica is unlinked
String	toString()
boolean	unlinkBlock(int numLinks) Remove a hard link by copying the block to a temporary place and then moving it back

Methods inherited from class org.apache.hadoop.hdfs.protocol.Block

appendStringTo, compareTo, equals, filename2id, getBlockId, getBlockId, getBlockName, getGenerationStamp, getGenerationStamp, getNumBytes, hashCode, isBlockFilename, isMetaFilename, matchingIdAndGenStamp, readFields, readId, set, setBlockId, setGenerationStamp, setNumBytes, write, writeId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.hadoop.hdfs.server.datanode.Replica

getBlockId, getBytesOnDisk, getGenerationStamp, getNumBytes, getState, getVisibleLength

Method Detail

getBlockFile

public File getBlockFile()

Get the full path of this replica's data file

Returns:

the full path of this replica's data file

getMetaFile

public File getMetaFile()

Get the full path of this replica's meta file

Returns:

the full path of this replica's meta file

getVolume

public FsVolumeSpi getVolume()

Get the volume where this replica is located on disk

Returns:

the volume where this replica is located on disk

setDir

public void setDir(File dir)

Set the parent directory where this replica is located

Parameters:

dir - the parent directory where the replica is located

parseSubDirs

public static ReplicaInfo.ReplicaDirInfo parseSubDirs(File dir)

isUnlinked

public boolean isUnlinked()

check if this replica has already been unlinked.

Returns:

true if the replica has already been unlinked or no need to be detached; false otherwise

setUnlinked

public void setUnlinked()

set that this replica is unlinked

unlinkBlock

public boolean unlinkBlock(int numLinks)
                    throws IOException

Remove a hard link by copying the block to a temporary place and then moving it back

Parameters:

numLinks - number of hard links

Returns:

true if copy is successful; false if it is already detached or no need to be detached

Throws:

IOException - if there is any copy error

toString

public String toString()

Overrides:

toString in class Block