org.apache.hadoop.hdfs.server.namenode

Class NullBlockAliasMap

java.lang.Object

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

org.apache.hadoop.hdfs.server.namenode.NullBlockAliasMap

@InterfaceAudience.Public
 @InterfaceStability.Unstable
public class NullBlockAliasMap
extends BlockAliasMap<FileRegion>

Null sink for region information emitted from FSImage.

Constructor Summary

Constructors

Constructor and Description
NullBlockAliasMap()

Method Summary

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

NullBlockAliasMap

public NullBlockAliasMap()

Method Detail

getReader

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

Description copied from class: BlockAliasMap

Returns a reader to the alias map.

Specified by:

getReader in class BlockAliasMap<FileRegion>

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

Description copied from class: BlockAliasMap

Returns the writer for the alias map.

Specified by:

getWriter in class BlockAliasMap<FileRegion>

Parameters:

opts - writer options.

blockPoolID - block pool id to use

Returns:

BlockAliasMap.Writer to the alias map.

Throws:

IOException

refresh

public void refresh()
             throws IOException

Description copied from class: BlockAliasMap

Refresh the alias map.

Specified by:

refresh in class BlockAliasMap<FileRegion>

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in class BlockAliasMap<FileRegion>

Throws:

IOException