alluxio.underfs

Class UnderFileSystemFactoryRegistry

java.lang.Object

alluxio.underfs.UnderFileSystemFactoryRegistry

@NotThreadSafe
public final class UnderFileSystemFactoryRegistry
extends Object

Central registry of available UnderFileSystemFactory instances that uses the ServiceLoader mechanism to automatically discover available factories and provides a central place for obtaining actual UnderFileSystem instances.

Note that if you are bundling Alluxio plus your code in a shaded JAR using Maven, make sure to use the ServicesResourceTransformer as otherwise your services file will override the core provided services file and leave the standard factories and under file system implementations unavailable.

See Also:

ExtensionFactoryRegistry

Method Summary

Modifier and Type	Method and Description
static List<UnderFileSystemFactory>	available() Returns a read-only view of the available base factories.
static UnderFileSystemFactory	find(String path, AlluxioConfiguration alluxioConf) Finds the first Under File System factory that supports the given path.
static UnderFileSystemFactory	find(String path, UnderFileSystemConfiguration ufsConf) Finds the first Under File System factory that supports the given path.
static List<UnderFileSystemFactory>	findAll(String path, UnderFileSystemConfiguration ufsConf) Finds all the Under File System factories that support the given path.
static List<String>	getSupportedVersions(String path, UnderFileSystemConfiguration ufsConf) Get a list of supported versions for a particular UFS path.
static void	register(UnderFileSystemFactory factory) Registers a new factory.
static void	reset() Resets the registry to its default state
static void	unregister(UnderFileSystemFactory factory) Unregisters an existing factory.

Methods inherited from class java.lang.Object

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

Method Detail

available

public static List<UnderFileSystemFactory> available()

Returns a read-only view of the available base factories.

Returns:

Read-only view of the available base factories

find

@Nullable
public static UnderFileSystemFactory find(String path,
                                                    AlluxioConfiguration alluxioConf)

Finds the first Under File System factory that supports the given path.

Parameters:

path - path

alluxioConf - Alluxio configuration

Returns:

factory if available, null otherwise

find

@Nullable
public static UnderFileSystemFactory find(String path,
                                                    UnderFileSystemConfiguration ufsConf)

Finds the first Under File System factory that supports the given path.

Parameters:

path - path

ufsConf - configuration object for the UFS

Returns:

factory if available, null otherwise

findAll

public static List<UnderFileSystemFactory> findAll(String path,
                                                   UnderFileSystemConfiguration ufsConf)

Finds all the Under File System factories that support the given path.

Parameters:

path - path

ufsConf - configuration of the UFS

Returns:

list of factories that support the given path which may be an empty list

getSupportedVersions

public static List<String> getSupportedVersions(String path,
                                                UnderFileSystemConfiguration ufsConf)

Get a list of supported versions for a particular UFS path.

Parameters:

path - the UFS URI to test

ufsConf - the UFS configuration for the mount

Returns:

a list of supported versions. The list will be empty if the particular UFS type does not support setting a version on the mount.

register

public static void register(UnderFileSystemFactory factory)

Registers a new factory.

Factories are registered at the start of the factories list so they can override the existing automatically discovered factories. Generally if you use the ServiceLoader mechanism properly it should be unnecessary to call this, however since ServiceLoader discovery order may be susceptible to class loader behavioral differences there may be rare cases when you need to manually register the desired factory.

Parameters:

factory - factory to register

reset

public static void reset()

Resets the registry to its default state

This clears the registry as it stands and rediscovers the available factories.

unregister

public static void unregister(UnderFileSystemFactory factory)

Unregisters an existing factory.

Parameters:

factory - factory to unregister