Package org.apache.hadoop.hdfs.server.common.blockaliasmap

Class BlockAliasMap<T extends BlockAlias>

java.lang.Object

org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap<T>

Direct Known Subclasses:

LevelDBFileRegionAliasMap, NullBlockAliasMap, TextFileRegionAliasMap

@Public
@Unstable
public abstract class BlockAliasMap<T extends BlockAlias>
extends Object

An abstract class used to read and write block maps for provided blocks.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.ImmutableIterator	ImmutableIterator is an Iterator that does not support the remove operation.
static class	org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader<U extends BlockAlias>	An abstract class that is used to read BlockAliases for provided blocks.
static class	org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer<U extends BlockAlias>	An abstract class used as a writer for the provided block map.

Constructor Summary

Constructors

Constructor	Description
BlockAliasMap()

Method Summary

Modifier and Type	Method	Description
abstract void	close()
abstract org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader<T>	getReader(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader.Options opts, String blockPoolID)	Returns a reader to the alias map.
abstract org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer<T>	getWriter(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer.Options opts, String blockPoolID)	Returns the writer for the alias map.
abstract void	refresh()	Refresh the alias map.

Methods inherited from class java.lang.Object

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

Constructor Details

BlockAliasMap

public BlockAliasMap()

Method Details

getReader

public abstract org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader<T> getReader(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader.Options opts,
 String blockPoolID)
                                                                                              throws IOException

Returns a reader to the alias map.

Parameters:

opts - reader options

blockPoolID - block pool id to use

Returns:

BlockAliasMap.Reader to the alias map. If a Reader for the blockPoolID cannot be created, this will return null.

Throws:

IOException

getWriter

public abstract org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer<T> getWriter(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer.Options opts,
 String blockPoolID)
                                                                                              throws IOException

Returns the writer for the alias map.

Parameters:

opts - writer options.

blockPoolID - block pool id to use

Returns:

BlockAliasMap.Writer to the alias map.

Throws:

IOException

refresh

public abstract void refresh()
                      throws IOException

Refresh the alias map.

Throws:

IOException

close

public abstract void close()
                    throws IOException

Throws:

IOException