Package org.apache.hadoop.hdfs.server.namenode

Class BlockResolver

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.BlockResolver

Direct Known Subclasses:

FixedBlockResolver

@Public
@Unstable
public abstract class BlockResolver
extends Object

Given an external reference, create a sequence of blocks and associated metadata.

Constructor Summary

Constructors

Constructor	Description
BlockResolver()

Method Summary

Modifier and Type	Method	Description
protected abstract List<Long>	blockLengths(FileStatus status)
protected org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto	buildBlock(long blockId, long bytes)
protected org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto	buildBlock(long blockId, long bytes, long genstamp)
abstract int	getReplication(FileStatus status)
protected abstract long	lastId()
abstract long	nextId()
long	preferredBlockSize(FileStatus status)
Iterable<org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto>	resolve(FileStatus s)

Methods inherited from class java.lang.Object

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

Constructor Details

BlockResolver

public BlockResolver()

Method Details

buildBlock

protected org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto buildBlock(long blockId,
 long bytes)

buildBlock

protected org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto buildBlock(long blockId,
 long bytes,
 long genstamp)

resolve

public Iterable<org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto> resolve(FileStatus s)

Parameters:

s - the external reference.

Returns:

sequence of blocks that make up the reference.

nextId

public abstract long nextId()

Returns:

the next block id.

lastId

protected abstract long lastId()

Returns:

the maximum sequentially allocated block ID for this filesystem.

blockLengths

protected abstract List<Long> blockLengths(FileStatus status)

Parameters:

status - the external reference.

Returns:

the lengths of the resultant blocks.

preferredBlockSize

public long preferredBlockSize(FileStatus status)

Parameters:

status - the external reference.

Returns:

the block size to assign to this external reference.

getReplication

public abstract int getReplication(FileStatus status)

Parameters:

status - the external reference.

Returns:

the replication to assign to this external reference.