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

Interface VolumeChooser

All Known Implementing Classes:

DelegatingChooser, PreferredVolumeChooser, RandomVolumeChooser, SpaceAwareVolumeChooser

public interface VolumeChooser

Helper used to select a volume from a set of Volume URIs.

Volumes will be selected based on defined option criteria. Note: Implementations must be threadsafe.
VolumeChooser.equals will be used for internal caching.

Property Details:
Property.GENERAL_ARBITRARY_PROP_PREFIX and Property.TABLE_ARBITRARY_PROP_PREFIX can be used to define user-specific properties to ensure separation from Accumulo System defaults.
Note: The default VolumeChooser implementation is set by Property.GENERAL_VOLUME_CHOOSER.

Since:

2.1.0

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 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)	Choose a volume from the provided options.

Method Detail

choose

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

Choose a volume from the provided options.

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

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

Return the subset of all possible volumes that could be chosen across all invocations of 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.