UserManager

java.lang.Object
- com.mckoi.database.UserManager

```
public final class UserManager
extends java.lang.Object
```
A class that manages the list of users connected to the engine.
This class is thread safe, however it is recommended that the callee should synchronize over this object when inspecting a subset of the user list. The reason being that a user can connect or disconnect at any time.

Field Summary

Fields
Modifier and Type Field Description

private java.util.ArrayList user_list
The list of User objects that are currently connected to the database engine.

Constructor Summary

Constructors
Constructor Description

UserManager()
Constructs the UserManager.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`User`	`userAt(int n)`	Returns the User object at index 'n' in the manager where 0 is the first user.
`int`	`userCount()`	Returns the number of users that are logged in.
`(package private) void`	`userLoggedIn(User user)`	Called when a new user connects to the engine.
`(package private) void`	`userLoggedOut(User user)`	Called when the user logs out of the engine.

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

- Field Detail
  - user_list
```
private java.util.ArrayList user_list
```
    The list of User objects that are currently connected to the database engine.
- Constructor Detail
  - UserManager
```
UserManager()
```
    Constructs the UserManager.
- Method Detail
  - userLoggedIn
```
void userLoggedIn(User user)
```
    Called when a new user connects to the engine.
  - userLoggedOut
```
void userLoggedOut(User user)
```
    Called when the user logs out of the engine.
  - userCount
```
public int userCount()
```
    Returns the number of users that are logged in.
  - userAt
```
public User userAt(int n)
```
    Returns the User object at index 'n' in the manager where 0 is the first user.