How to seperate logic from controller JavaFx

问题

I've got an issue with seperating business logic from controller (apart from that how i'm validating data in my program).

Here is logic class:

public class LogInMechanism {

LogInController logInController = new LogInController();
private static int howManyAttempts=0;

public void logIn()
{
howManyAttempts++;
if(howManyAttempts <3)
{
    if(logInController.getLogInField().getText().equals("nick") && logInController.getPasswordField().getText().equals("password"))
    {
        System.out.println("Button clicked");
        try {
            Parent root = FXMLLoader.load(getClass().getResource("/fxml/MainWindow.fxml"));
            logInController.getLogInField().getScene().setRoot(root);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    else
    {
        logInController.getInvalidUserOrPasswordLabel().setText("Invalid user or password "+(3-howManyAttempts)+ " attempts left!");
        logInController.getInvalidUserOrPasswordLabel().setVisible(true);
    }
}
else
{

    logInController.getInvalidUserOrPasswordLabel().setDisable(true);
    logInController.getInvalidUserOrPasswordLabel().setText("Your program has been blocked. Please contact manager!");


}
}


}

And i want this function to be used in one of my controllers

public class LogInController {
private LogInMechanism logInMechanism = new LogInMechanism();

@FXML
private Label invalidUserOrPasswordLabel;

@FXML
private TextField logInField;

@FXML
private Button logInButton;

@FXML
private PasswordField passwordField;

@FXML
void logInButtonClicked(ActionEvent event) {
    logInMechanism.logIn();
}

@FXML
public void initialize()
{
    EventHandler<KeyEvent> handlerLambda = e ->{
        if(e.getCode()==KeyCode.ENTER)
        {
        //  logInMechanism.logIn();
        }

    };
    logInButton.addEventHandler(KeyEvent.KEY_PRESSED, handlerLambda);
}

public Label getInvalidUserOrPasswordLabel() {
    return invalidUserOrPasswordLabel;
}

public TextField getLogInField() {
    return logInField;
}

public PasswordField getPasswordField() {
    return passwordField;
}

But unfortunatelly ifter performing such code i recieve an error:

Exception in Application start method
java.lang.reflect.InvocationTargetException
Caused by: java.lang.RuntimeException: Exception in Application start method
Caused by: java.lang.StackOverflowError

The error appears at line 19 in LogInMechanism class. I'm still learning though, if you have any suggestions please share.

来源：https://stackoverflow.com/questions/44913531/how-to-seperate-logic-from-controller-javafx

标签

java

javafx