Keep Java Thread running all the time

Question

Looking for an elegant way to keep a Java thread running all the time in the background, as long as the application is running, for a JavaFX app checking to see is the User Credentials are valid or not. What I would be doing inside the Thread is expiring the users after certain interval

Answer 1

If you want to timeout the login you can use a PauseTransition to expire the login:

Duration timeout = Duration.minutes(...);
PauseTransition logoutTimer = new PauseTransition(timeout);
logoutTimer.setOnFinished(e -> expireCredentials());
logoutTimer.play();

If you need to reset the timeout at any point, you can just do

logoutTimer.playFromStart();

and it will reset the timer.

You can also use JavaFX properties to make this easy to manage in the application. E.g.

private BooleanProperty loggedIn = new SimpleBooleanProperty();

// ...

public void expireCredentials() {
    loggedIn.set(false);
}

Then operations which require the user to be logged in can check this property:

if (loggedIn.get()) {
    doSecureOperation();
}

and UI controls can bind their states to it:

submitSecureDataButton.disableProperty().bind(loggedIn.not());
loginButton.disableProperty().bind(loggedIn);

or perhaps

private ObjectProperty<Credentials> credentials = new SimpleObjectProperty<>();

// ...

public void expireCredentials() {
    credentials.set(null);
}

// ...

submitSecureDataButton.disableProperty().bind(credentials.isNull());
loginButton.disableProperty().bind(credentials.isNotNull());