DelegatingChooser (Apache Accumulo Core 2.1.0 API)

java.lang.Object
- org.apache.accumulo.core.spi.fs.DelegatingChooser

All Implemented Interfaces:

VolumeChooser
```
public class DelegatingChooser
extends Object
implements VolumeChooser
```
A VolumeChooser that delegates to another volume chooser based on other properties: table.custom.volume.chooser for tables, and general.custom.volume.chooser.scoped for scopes. general.custom.volume.chooser.{scope} can override the system-wide setting for general.custom.volume.chooser.scoped. At the time this was written, the only known scope was "logger".

Since:

2.1.0

Constructor Summary

Constructors
Constructor Description

DelegatingChooser()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Set<String>`	`choosable(VolumeChooserEnvironment env, Set<String> options)`	Return the subset of volumes that could possibly be chosen by this chooser across all invocations of `VolumeChooser.choose(VolumeChooserEnvironment, Set)`.
`String`	`choose(VolumeChooserEnvironment env, Set<String> options)`	Choose a volume from the provided options.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DelegatingChooser
```
public DelegatingChooser()
```
- Method Detail
  - choose
```
public String choose(VolumeChooserEnvironment env,
                     Set<String> options)
```
    Description copied from interface: VolumeChooser
    
    Choose a volume from the provided options.
    
    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:
    
    one of the options
  - choosable
```
public Set<String> choosable(VolumeChooserEnvironment env,
                             Set<String> options)
```
    Description copied from interface: VolumeChooser
    
    Return the subset of volumes that could possibly be chosen by this chooser across all invocations of VolumeChooser.choose(VolumeChooserEnvironment, Set). Currently this is used to determine if all of the volumes that could be chosen for write ahead logs support the needed filesystem operations. There may be other use cases in the future.
    
    Specified by:
    
    choosable in interface VolumeChooser
    
    Parameters:
    
    env - the server environment provided by the calling framework
    
    options - the subset of volumes to choose from
    
    Returns:
    
    array of valid options