Christoph Frick - ofnir.net - Open Source Consultant, Software Developer and System Administrator (Posts about Vaadin)

I am a Certified Vaadin 24 Developer now

Christoph Frick - ofnir.net — Tue, 05 Dec 2023 23:00:00 GMT

What the title says :)

Using Groovy for Vaadin Hilla endpoints

Christoph Frick - ofnir.net — Sun, 02 Jul 2023 22:00:00 GMT

Since version 2 Vaadin Hilla no longer needs endpoints to be .java files to be parsed. Now the endpoints are determined by analyzing the generated classes. So in theory any JVM language can be used now for endpoints - as long as the result comes close enough to what the Java compiler would produce.

For Groovy this means to annotate the @dev.hilla.Enpoint classes with @groovy.transform.stc.POJO and @groovy.transform.CompileStatic.

@CompileStatic is no stranger, but @POJO is new since Groovy 4.0; both combined will result in byte-code, that is very close to what the Java compiler would produce from a similar .java file. Yet you are still able to use Groovy code and annotations.

Complete example:

package com.example.application.helloworld

import com.vaadin.flow.server.auth.AnonymousAllowed
import dev.hilla.Endpoint
import jakarta.annotation.Nonnull
import jakarta.validation.constraints.NotEmpty

@Endpoint
@AnonymousAllowed
@groovy.transform.stc.POJO      // XXX
@groovy.transform.CompileStatic // XXX
class HelloWorldEndpoint {

    private final HelloWorldService helloWorldService

    HelloWorldEndpoint(HelloWorldService helloWorldService) {
        this.helloWorldService = helloWorldService
    }

    @Nonnull
    String sayHello(@NotEmpty String name) {
        return helloWorldService.sayHello(name)
    }
}

Vaadin Flow cheat sheets and flow diagrams

Christoph Frick - ofnir.net — Mon, 11 Apr 2022 22:00:00 GMT

Started a project to put together the more intricate correlations that make the Vaadin Flow framework tick.

Vaadin Flow Cheat sheets and flow diagrams

First one is the navigation life cycle:

I am a Certified Vaadin 14 Professional now

Christoph Frick - ofnir.net — Wed, 29 Apr 2020 22:00:00 GMT

What the title says :)

I am a Certified Vaadin 14 Developer now

Christoph Frick - ofnir.net — Tue, 24 Mar 2020 23:00:00 GMT

What the title says :)

I am a Certified Vaadin 8 Developer and Professional now

Christoph Frick - ofnir.net — Mon, 04 Sep 2017 22:00:00 GMT

What the title says :)

Generic Vaadin8 field for converted values

Christoph Frick - ofnir.net — Mon, 24 Apr 2017 22:00:00 GMT

In Vaadin8 the conversion between the model data type and the field is done in the Binder. This prevents automatic mapping for the models as some manual step must be done beforehand. But since writing custom fields now is way more reasonable, here is a first draft for a generic converter field. Just provide the backing Field and an Converter.

https://gist.github.com/christoph-frick/947fec59cfd09f7140933b52102cc041

Null representation needed when using converters in Vaadin 8 binder

Christoph Frick - ofnir.net — Thu, 02 Mar 2017 23:00:00 GMT

TextFields in Vaadin8 are no longer allowed to get a null set as value. This usually is no problem unless we use a Converter for the field binding. In that case a null value about to be bound will raise an assertion error. It also won't help if that field is bound with asRequired.

The solution in this case is to use withNullRepresentation before adding the Converter in the binding builder. This adds another converter at first, that turns null values into "something" so the real converter has to actually work.

See

https://github.com/christoph-frick/try-vaadin8/commit/8eee2ce6880b7a3dd4ce1526cf533ef356d3ec50

and

https://github.com/vaadin/framework/issues/8725

Trying out Vaadin 8

Christoph Frick - ofnir.net — Thu, 16 Feb 2017 23:00:00 GMT

Started a repo to try out the new/changed stuff from Vaadin 8. Lessons learned so far:

Immediate on fields is gone. They are now immediate by default.
Converter on fields is gone. You convert either in the Binder or you have to write your own field.
Use the Binder builder as a builder (chain your calls) -- even if your e.g. Groovy gives you builderish behaviour with with.
The CallbackDataProvider is basically the same as the LazyContainer from Viritin.
Creating your own CustomField becomes easier, since you get some proper guidance on what to implement. Yet making that field properly propagate change events is still on you.
For a composite field it's easiest to build it up using again a Binder and delegate addValueChangeListener down to it.

The repository is here: https://github.com/christoph-frick/try-vaadin8

Updated Vaadin starter to official Spring plugin

Christoph Frick - ofnir.net — Mon, 15 Aug 2016 22:00:00 GMT

Finally came around to update the Spring-Boot Groovy Vaadin Starter to the official Spring plugin. The only major difference now is the handling of the widgetset via annotation instead of configuration.

Also the "close-to-tweetable" example got an update.

// run with `spring run vaadin.groovy`
@Grapes([
@Grab('com.vaadin:vaadin-spring-boot-starter:1.0.0'),
@Grab('com.vaadin:vaadin-archetype-application:7.6.8'),
])
import com.vaadin.ui.*

@com.vaadin.spring.annotation.SpringUI
@com.vaadin.annotations.Theme("valo")
class MyUI extends UI {
        protected void init(com.vaadin.server.VaadinRequest request) {
                setContent(new Label("Hello World!"))
        }
}