UserState (Alluxio Core - Common Utilities 295 API)

All Known Implementing Classes:

BaseUserState, NoopUserState, SimpleUserState
```
public interface UserState
```
UserState handles logging in any client, and maintains the state. The UserState provides access to the Subject and the User for the client.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class UserState.Factory
A factory for creating a UserState.

Field Summary

Fields
Modifier and Type Field Description

static java.util.ArrayList<UserStateFactory> FACTORIES
An ordered list of factories for creating UserState instances.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`javax.security.auth.Subject`	`getSubject()`	Returns the Subject for this user.
`User`	`getUser()`	Returns the User object for this user.
`User`	`relogin()`	Attempts to log in again, and returns the new User.
`default void`	`update(UserState otherUserState)`	Use a new user state to update the credentials in the current user state.

- Field Detail
  - FACTORIES
```
static final java.util.ArrayList<UserStateFactory> FACTORIES
```
    An ordered list of factories for creating UserState instances. The UserState factories are tried in order, from first to last.
- Method Detail
  - getSubject
```
javax.security.auth.Subject getSubject()
```
    Returns the Subject for this user. Attempts to log in if not already logged in.
    
    Returns:
    
    the Subject for this user state
  - getUser
```
User getUser()
      throws UnauthenticatedException
```
    Returns the User object for this user. Attempts to log in if not already logged in.
    
    Returns:
    
    the User for this user state
    
    Throws:
    
    UnauthenticatedException - if the attempted login failed
  - relogin
```
User relogin()
      throws UnauthenticatedException
```
    Attempts to log in again, and returns the new User.
    
    Returns:
    
    the User for this user state, after the relogin
    
    Throws:
    
    UnauthenticatedException - if the re-login failed
  - update
```
default void update(UserState otherUserState)
             throws java.io.IOException
```
    Use a new user state to update the credentials in the current user state.
    
    Parameters:
    
    otherUserState - the new user state for credentials update
    
    Throws:
    
    java.io.IOException