[[auth:intro|Intro]]
[[auth:ex1|Ex1]]
[[auth:ex2|Ex2]]
[[auth:ex3|Ex3]]
[[auth:ex4|Ex4]]====== Authentication: Enforce authenticated user ======

Extend your aspect to enforce an authenticated user when ''@Authenticated'' methods or constructors are executed.

To model the authentication, we will present the user with an input dialog where he/she can select the role. (This is of course a simplification: in production, we would of course have to prompt for login and password and verify these against a password database.)

The code to manage the current role for the user and to present the authentication dialog is shown here:

<code aspectj>
import javax.swing.JOptionPane;
import figures.annotations.Authenticated;

public aspect AccessControl {
  ...
  Authenticated.Role role;

  public void authenticate() {
    role = (Authenticated.Role)
      JOptionPane.showInputDialog(null,
        "Select role", "Input",
        JOptionPane.INFORMATION_MESSAGE, null,
        Authenticated.Role.values(), role);
  }
  ...
}
</code>

As long as the user is not authenticated, we keep presenting him the authentication dialog. In other words, the actual access control check can be as simple as:

<code aspectj>
while(role == null)
  authenticate();
</code>

After implementing the aspect, run the figure editor. You should be presented with the authentication dialog upon drawing the first point. Afterwards, new points can be added without interruption.

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Continue with [[auth:ex3|Exercise 3]].