Package org.apache.accumulo.core.spi.fs

Class RandomVolumeChooser

java.lang.Object

org.apache.accumulo.core.spi.fs.RandomVolumeChooser

All Implemented Interfaces:

VolumeChooser

Direct Known Subclasses:

PreferredVolumeChooser

public class RandomVolumeChooser
extends Object
implements VolumeChooser

A VolumeChooser that selects a volume at random from the list of provided volumes.

Since:

2.1.0

Constructor Summary

Constructors

Constructor	Description
RandomVolumeChooser()

Method Summary

Modifier and Type	Method	Description
Set<String>	choosable(VolumeChooserEnvironment env, Set<String> options)	Return the subset of all possible volumes that could be chosen across all invocations of VolumeChooser.choose(VolumeChooserEnvironment, Set). This is currently used to determine if the chosen volumes can support the required filesystem operations for write ahead logs. There may be other use cases in the future.
String	choose(VolumeChooserEnvironment env, Set<String> options)	Selects a volume at random from the provided set of volumes.

Methods inherited from class java.lang.Object

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

Constructor Details

RandomVolumeChooser

public RandomVolumeChooser()

Method Details

choose

public String choose(VolumeChooserEnvironment env,
 Set<String> options)

Selects a volume at random from the provided set of volumes. The environment scope is not utilized.

Specified by:

choose in interface VolumeChooser

Parameters:

env - the server environment provided by the calling framework

options - the list of volumes to choose from

Returns:

a volume from the list of volume options

choosable

public Set<String> choosable(VolumeChooserEnvironment env,
 Set<String> options)

Description copied from interface: VolumeChooser

Return the subset of all possible volumes that could be chosen across all invocations of VolumeChooser.choose(VolumeChooserEnvironment, Set).
This is currently used to determine if the chosen volumes can support the required filesystem operations for write ahead logs.
There may be other use cases in the future.

Specified by:

choosable in interface VolumeChooser

Returns:

same set of volume options that were originally provided.