GroupMappingService (Alluxio Core - Common Utilities 294 API)

All Known Implementing Classes:

CachedGroupMapping, IdentityUserGroupsMapping, ShellBasedUnixGroupsMapping
```
@PublicApi
public interface GroupMappingService
```
Interface for Alluxio user-to-groups mapping. GroupMappingService allows for server to get the various group memberships of a given user via the getGroups(String) call, thus ensuring a consistent user-to-groups mapping and protects against mapping inconsistencies between servers and clients in an Alluxio cluster.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class GroupMappingService.Factory
Factory for creating a new instance.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.util.List<java.lang.String>`	`getGroups(java.lang.String user)`	Gets all various group memberships of a given user.

- Method Detail
  - getGroups
```
java.util.List<java.lang.String> getGroups(java.lang.String user)
                                    throws java.io.IOException
```
    Gets all various group memberships of a given user. Returns EMPTY list in case of non-existing user.
    
    Parameters:
    
    user - user's name
    
    Returns:
    
    group memberships of user
    
    Throws:
    
    java.io.IOException