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 a Jetty. 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 src path.

public class HelloWorld {
  public static void main(String[] args) {
    new CoreUIService().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.