Generate Login View

In the Project Management > User Interface click on Create new GUI element.
In the following dialog, specify a name for the view at Name.
Select Template > Login View with Login Form.
Click Finish.
Click OK in the following note about the RapidClipse framework.
In the following dialog, select your Authenticator Provider.
Click on Finish.

Result:

GUI Builder - A default login view is generated in the GUI Builder.

Javacode - All javacode for this will be generated automatically.

package com.company.demoproject.ui;

import com.company.demoproject.MyAuthenticationProvider;
import com.rapidclipse.framework.security.authentication.CredentialsUsernamePassword;
import com.rapidclipse.framework.server.security.authentication.Authentication;
import com.vaadin.flow.component.ComponentEvent;
import com.vaadin.flow.component.ComponentEventListener;
import com.vaadin.flow.component.login.AbstractLogin.ForgotPasswordEvent;
import com.vaadin.flow.component.login.AbstractLogin.LoginEvent;
import com.vaadin.flow.component.login.LoginForm;
import com.vaadin.flow.component.orderedlayout.FlexComponent;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;


@com.rapidclipse.framework.server.security.authentication.LoginView
public class LoginView extends VerticalLayout
{
    public LoginView()
    {
        super();
        initUI();
    }

    /**
     * Event handler delegate method for the {@link LoginForm} {@link #loginForm}.
     *
     * @see ComponentEventListener#onComponentEvent(ComponentEvent)
     * @eventHandlerDelegate Do NOT delete, used by UI designer!
     */
    private void loginForm_onLogin(final LoginEvent event)
    {
        final CredentialsUsernamePassword credentials = CredentialsUsernamePassword.New(
            event.getUsername(), event.getPassword());

        MyAuthenticationProvider authenticatorProvider = MyAuthenticationProvider.getInstance();

        if(!Authentication.tryLogin(credentials, authenticatorProvider))
        {
            this.loginForm.setError(true);
        }
    }

    /**
     * Event handler delegate method for the {@link LoginForm} {@link #loginForm}.
     *
     * @see ComponentEventListener#onComponentEvent(ComponentEvent)
     * @eventHandlerDelegate Do NOT delete, used by UI designer!
     */
    private void loginForm_onForgotPassword(final ForgotPasswordEvent event)
    {
        // TODO provide password recovery
    }

    /* WARNING: Do NOT edit!<br>The content of this method is always regenerated by the UI designer. */
    // <generated-code name="initUI">
    private void initUI()
    {
        this.loginForm = new LoginForm();

        this.setJustifyContentMode(FlexComponent.JustifyContentMode.CENTER);
        this.setDefaultHorizontalComponentAlignment(FlexComponent.Alignment.CENTER);

        this.add(this.loginForm);
        this.setSizeFull();

        this.loginForm.addLoginListener(this::loginForm_onLogin);
        this.loginForm.addForgotPasswordListener(this::loginForm_onForgotPassword);
    } // </generated-code>

    // <generated-code name="variables">
    private LoginForm loginForm;
    // </generated-code>

}