alluxio.client.file.policy

Class RoundRobinPolicy

java.lang.Object

alluxio.client.file.policy.RoundRobinPolicy

All Implemented Interfaces:

BlockLocationPolicy, FileWriteLocationPolicy

@NotThreadSafe
public final class RoundRobinPolicy
extends Object
implements FileWriteLocationPolicy, BlockLocationPolicy

A policy that chooses the worker for the next block in a round-robin manner and skips workers that do not have enough space. The policy returns null if no worker can be found.

Nested Class Summary

Nested classes/interfaces inherited from interface alluxio.client.block.policy.BlockLocationPolicy

BlockLocationPolicy.Factory

Constructor Summary

Constructors

Constructor and Description
RoundRobinPolicy() Constructs a new RoundRobinPolicy.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
WorkerNetAddress	getWorker(GetWorkerOptions options) Gets the worker's network address for serving operations requested for the block.
WorkerNetAddress	getWorkerForNextBlock(Iterable<BlockWorkerInfo> workerInfoList, long blockSizeBytes) The policy uses the first fetch of worker info list as the base, and visits each of them in a round-robin manner in the subsequent calls.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

RoundRobinPolicy

public RoundRobinPolicy()

Constructs a new RoundRobinPolicy.

Method Detail

getWorkerForNextBlock

@Nullable
public WorkerNetAddress getWorkerForNextBlock(Iterable<BlockWorkerInfo> workerInfoList,
                                                        long blockSizeBytes)

The policy uses the first fetch of worker info list as the base, and visits each of them in a round-robin manner in the subsequent calls. The policy doesn't assume the list of worker info in the subsequent calls has the same order from the first, and it will skip the workers that are no longer active.

Specified by:

getWorkerForNextBlock in interface FileWriteLocationPolicy

Parameters:

workerInfoList - the info of the active workers

blockSizeBytes - the size of the block in bytes

Returns:

the address of the worker to write to

getWorker

@Nullable
public WorkerNetAddress getWorker(GetWorkerOptions options)

Description copied from interface: BlockLocationPolicy

Gets the worker's network address for serving operations requested for the block.

Specified by:

getWorker in interface BlockLocationPolicy

Parameters:

options - the options to get a block worker network address for a block

Returns:

the address of the worker to write to, null if no worker can be selected

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object