Nano Vaadin - Ramp up in a second.

A nano project to start a Vaadin project. Perfect for Micro-UIs packed as fat jar in a docker image.

Supported JDK

This example is running from JDK8 up to JDK13

Support for Heroku

To support the Heroku pipeline we need a few preparations.

1. the app must be able to get a configured port for the http port during the start up
2. add the shade plugin to create a fat jar
3. create the file Procfile and add the line ``web: java -jar target/vaadin-app.jar -port $PORT```
   • web - to activate the web profile
   • -jar - define what fat jar must be started
   • -port make the dynamic associated port available for the app
4. add a file settings.xml to configure the maven build process

target of this project

The target of this project is a minimal rampup time for a first hello world. Why we need one more HelloWorld? Well, the answer is quite easy. If you have to try something out, or you want to make a small POC to present something, there is no time and budget to create a demo project. You don´t want to copy paste all small things together. Here you will get a Nano-Project that will give you all in a second.

Clone the repo and start editing the class HelloWorld and VaadinApp. Nothing more.

How does it work?

Internally it will ramp up an Undertow. If you want to see how this is done, have a look inside the class CoreUIService.

How a developer can use this

You as a developer can use it like it is shown in the demo folder inside the test src path.

public class HelloWorld {
  public static void main(String[] args) {
    new CoreUIService() {
      @Override
      public Set<Class<?>> setOfRouteAnnotatedClasses() {
        return Collections.singleton(VaadinApp.class);
      }
    }.startup();
  }
}

@Route("")
public class VaadinApp extends Composite<Div> implements HasLogger {

  public static final String BTN_CLICK_ME   = "btn-click-me";
  public static final String LB_CLICK_COUNT = "lb-click-count";

  private final Button         btnClickMe   = new Button("click me");
  private final Span           lbClickCount = new Span("0");
  private final VerticalLayout layout       = new VerticalLayout(btnClickMe, lbClickCount);

  private int clickcount = 0;

  public VaadinApp() {
    btnClickMe.setId(BTN_CLICK_ME);
    btnClickMe.addClickListener(event -> lbClickCount.setText(String.valueOf(++clickcount)));

    lbClickCount.setId(LB_CLICK_COUNT);

    logger().info("and now..  setting the main content.. ");
    getContent().add(layout);
  }
}

Happy Coding.

if you have any questions: ping me on Twitter https://twitter.com/SvenRuppert or via mail.

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