A simple Login Screen - boring but usefull ;-) This is for Vaadin 10, build on a JDK10 but with

    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.source>1.8</maven.compiler.source>

A Login Screen is often used, and a repetive task to create if you are creating smaller apps, demos, and so on.

For this I created the component, da work with dependencies instead of copy-paste. even in my examples.

You can use this as a dependency. The only thing you have to do is to create the the connection to your app.

The first method to create is the method with the name public abstract boolean checkCredentials();

Here you have to decide if the provided credentials are valid or not. In the demo/test Source folder you will find the class MyLoginView The implementation in this class is for demo usage only.

  @Override
  public boolean checkCredentials() {
    String username = username();
    String password = password();

    // USE Apache Shiro for example : demo you can find here
    // https://github.com/Nano-Vaadin-Demos/nano-vaadin-meecrowave-shiro-V10

    // DON NOT USE THIS IN PRODUCTION !!
    boolean isOK = username != null && username.equals("admin") ||
                   password != null && password.equals("admin");

    UI.getCurrent().getSession().setAttribute(LOGGED_IN, isOK);
    // DON NOT USE THIS IN PRODUCTION !!

    return isOK;
  }

Define what should happen if the Auth-Service will reject the provided credentials. In this example there will be a Notification shown and a logger message created.

  @Override
  public void reactOnFailedLogin() {
    logger().warning("Login is not acctepd..");
    Notification.show("Credentials not accepted..");
  }

Now we can redirect to the next View. In this example a demo view with no special meaning.

  @Override
  public void navigateToApp() {
    UI.getCurrent().navigate(MainView.class);
  }

In the test folders you will find a fully working demo app to show a dummy implementation. If you want to see samo more examples, for example how to use this with Shiro, have a look at https://github.com/Nano-Vaadin-Demos/nano-vaadin-meecrowave-shiro-V10

• I18n will be added
• TDD / PageObjects based on Testbench NG and jUnit5

Feel free to ping me ..

• email sven.ruppert (a) gmail.com
• Twitter - @SvenRuppert