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 java.lang.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 java.util.List<java.lang.Long>	blockLengths(org.apache.hadoop.fs.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(org.apache.hadoop.fs.FileStatus status)
protected abstract long	lastId()
abstract long	nextId()
long	preferredBlockSize(org.apache.hadoop.fs.FileStatus status)
java.lang.Iterable<org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto>	resolve(org.apache.hadoop.fs.FileStatus s)

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockResolver

public BlockResolver()

Method Detail

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 java.lang.Iterable<org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto> resolve(org.apache.hadoop.fs.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 java.util.List<java.lang.Long> blockLengths(org.apache.hadoop.fs.FileStatus status)

Parameters:

status - the external reference.

Returns:

the lengths of the resultant blocks.

preferredBlockSize

public long preferredBlockSize(org.apache.hadoop.fs.FileStatus status)

Parameters:

status - the external reference.

Returns:

the block size to assign to this external reference.

getReplication

public abstract int getReplication(org.apache.hadoop.fs.FileStatus status)

Parameters:

status - the external reference.

Returns:

the replication to assign to this external reference.