Package org.apache.hadoop.hdfs.protocol

Class BlockStoragePolicy

java.lang.Object

org.apache.hadoop.hdfs.protocol.BlockStoragePolicy

All Implemented Interfaces:

org.apache.hadoop.fs.BlockStoragePolicySpi

@Private
public class BlockStoragePolicy
extends java.lang.Object
implements org.apache.hadoop.fs.BlockStoragePolicySpi

A block storage policy describes how to select the storage types for the replicas of a block.

Field Summary

Fields

Modifier and Type	Field	Description
static org.slf4j.Logger	LOG

Constructor Summary

Constructors

Constructor	Description
BlockStoragePolicy(byte id, java.lang.String name, org.apache.hadoop.fs.StorageType[] storageTypes, org.apache.hadoop.fs.StorageType[] creationFallbacks, org.apache.hadoop.fs.StorageType[] replicationFallbacks)
BlockStoragePolicy(byte id, java.lang.String name, org.apache.hadoop.fs.StorageType[] storageTypes, org.apache.hadoop.fs.StorageType[] creationFallbacks, org.apache.hadoop.fs.StorageType[] replicationFallbacks, boolean copyOnCreateFile)

Method Summary

Modifier and Type	Method	Description
java.util.List<org.apache.hadoop.fs.StorageType>	chooseExcess(short replication, java.lang.Iterable<org.apache.hadoop.fs.StorageType> chosen)	Choose excess storage types for deletion, given the replication number and the storage types of the chosen replicas.
java.util.List<org.apache.hadoop.fs.StorageType>	chooseStorageTypes(short replication)
java.util.List<org.apache.hadoop.fs.StorageType>	chooseStorageTypes(short replication, java.lang.Iterable<org.apache.hadoop.fs.StorageType> chosen)	Choose the storage types for storing the remaining replicas, given the replication number and the storage types of the chosen replicas.
java.util.List<org.apache.hadoop.fs.StorageType>	chooseStorageTypes(short replication, java.lang.Iterable<org.apache.hadoop.fs.StorageType> chosen, java.util.EnumSet<org.apache.hadoop.fs.StorageType> unavailables, boolean isNewBlock)	Choose the storage types for storing the remaining replicas, given the replication number, the storage types of the chosen replicas and the unavailable storage types.
boolean	equals(java.lang.Object obj)
org.apache.hadoop.fs.StorageType	getCreationFallback(java.util.EnumSet<org.apache.hadoop.fs.StorageType> unavailables)
org.apache.hadoop.fs.StorageType[]	getCreationFallbacks()
byte	getId()
java.lang.String	getName()
org.apache.hadoop.fs.StorageType	getReplicationFallback(java.util.EnumSet<org.apache.hadoop.fs.StorageType> unavailables)
org.apache.hadoop.fs.StorageType[]	getReplicationFallbacks()
org.apache.hadoop.fs.StorageType[]	getStorageTypes()
int	hashCode()
boolean	isCopyOnCreateFile()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.slf4j.Logger LOG

Constructor Detail

BlockStoragePolicy

@VisibleForTesting
public BlockStoragePolicy(byte id,
                          java.lang.String name,
                          org.apache.hadoop.fs.StorageType[] storageTypes,
                          org.apache.hadoop.fs.StorageType[] creationFallbacks,
                          org.apache.hadoop.fs.StorageType[] replicationFallbacks)

BlockStoragePolicy

@VisibleForTesting
public BlockStoragePolicy(byte id,
                          java.lang.String name,
                          org.apache.hadoop.fs.StorageType[] storageTypes,
                          org.apache.hadoop.fs.StorageType[] creationFallbacks,
                          org.apache.hadoop.fs.StorageType[] replicationFallbacks,
                          boolean copyOnCreateFile)

Method Detail

chooseStorageTypes

public java.util.List<org.apache.hadoop.fs.StorageType> chooseStorageTypes(short replication)

Returns:

a list of StorageTypes for storing the replicas of a block.

chooseStorageTypes

public java.util.List<org.apache.hadoop.fs.StorageType> chooseStorageTypes(short replication,
                                                                           java.lang.Iterable<org.apache.hadoop.fs.StorageType> chosen)

Choose the storage types for storing the remaining replicas, given the replication number and the storage types of the chosen replicas.

Parameters:

replication - the replication number.

chosen - the storage types of the chosen replicas.

Returns:

a list of StorageTypes for storing the replicas of a block.

chooseStorageTypes

public java.util.List<org.apache.hadoop.fs.StorageType> chooseStorageTypes(short replication,
                                                                           java.lang.Iterable<org.apache.hadoop.fs.StorageType> chosen,
                                                                           java.util.EnumSet<org.apache.hadoop.fs.StorageType> unavailables,
                                                                           boolean isNewBlock)

Choose the storage types for storing the remaining replicas, given the replication number, the storage types of the chosen replicas and the unavailable storage types. It uses fallback storage in case that the desired storage type is unavailable.

Parameters:

replication - the replication number.

chosen - the storage types of the chosen replicas.

unavailables - the unavailable storage types.

isNewBlock - Is it for new block creation?

Returns:

a list of StorageTypes for storing the replicas of a block.

chooseExcess

public java.util.List<org.apache.hadoop.fs.StorageType> chooseExcess(short replication,
                                                                     java.lang.Iterable<org.apache.hadoop.fs.StorageType> chosen)

Choose excess storage types for deletion, given the replication number and the storage types of the chosen replicas.

Parameters:

replication - the replication number.

chosen - the storage types of the chosen replicas.

Returns:

a list of StorageTypes for deletion.

getCreationFallback

public org.apache.hadoop.fs.StorageType getCreationFallback(java.util.EnumSet<org.apache.hadoop.fs.StorageType> unavailables)

Returns:

the fallback StorageType for creation.

getReplicationFallback

public org.apache.hadoop.fs.StorageType getReplicationFallback(java.util.EnumSet<org.apache.hadoop.fs.StorageType> unavailables)

Returns:

the fallback StorageType for replication.

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getId

public byte getId()

getName

public java.lang.String getName()

Specified by:

getName in interface org.apache.hadoop.fs.BlockStoragePolicySpi

getStorageTypes

public org.apache.hadoop.fs.StorageType[] getStorageTypes()

Specified by:

getStorageTypes in interface org.apache.hadoop.fs.BlockStoragePolicySpi

getCreationFallbacks

public org.apache.hadoop.fs.StorageType[] getCreationFallbacks()

Specified by:

getCreationFallbacks in interface org.apache.hadoop.fs.BlockStoragePolicySpi

getReplicationFallbacks

public org.apache.hadoop.fs.StorageType[] getReplicationFallbacks()

Specified by:

getReplicationFallbacks in interface org.apache.hadoop.fs.BlockStoragePolicySpi

isCopyOnCreateFile

public boolean isCopyOnCreateFile()

Specified by:

isCopyOnCreateFile in interface org.apache.hadoop.fs.BlockStoragePolicySpi