Karibu-DSL (Vaadin Kotlin Extensions)

This is a Kotlin extensions and DSL library for the Vaadin framework.

Need a button? Write button {}. Need a text field? Write textField {}. Need a layout? Write

verticalLayout {
    val nameField = textField("Your name") {}
    button("Click me") {
        setPrimary()
        onClick { Notification.show("Hello, ${nameField.value}") }
    }
}

Build own components and views by composing existing components with layouts.

This library:

• Allows you to create Vaadin UI designs in the structured code way; the idea behind the library is explained in the DSLs: Explained for Vaadin article. The general DSL idea is explained in Kotlin Type-Safe Builders.
• Includes useful components like PopupButton and TabSheet
• Contains additional useful methods which Vaadin lacks; see karibu-tools

Compatibility chart:

Vaadin Version	Karibu DSL Version	Min. Java Version	Maintained
24.5+	2.2.0+	17	yes
24+	2.0.0+	17	no
23	1.x	11	no
14-22	1.x	8	no
8	1.0.x	5	no

UI Basic Example Application

A very simple Gradle-based example application is located here: karibu-helloworld-application The project only shows a very simple Button, which makes it an ideal quick start application for experimenting and further development.

To check out the example app and run it:

git clone https://github.com/mvysny/karibu-helloworld-application
cd karibu-helloworld-application
./gradlew run

The app will run on http://localhost:8080.

The "Beverage Buddy" Example Application

The Beverage Buddy VoK is a more complex example app. It's the Vaadin Beverage Buddy app backed by an in-memory H2 database. You can quickly run the bundled example application from the command-line:

git clone https://github.com/mvysny/beverage-buddy-vok
cd beverage-buddy-vok
./gradlew appRun

The example app will be running at http://localhost:8080.

Documentation/Tutorial

>>> Documentation + Tutorial <<<: Please read the Karibu-DSL Vaadin 14+ tutorial.

The origins of the word Karibu: it's a term for North American subspecies of the reindeer; that connects to Vaadin (which is a Finnish word for a female reindeer). A nice connotation comes from Swahili where Karibu means welcome.

Note: For Groovy Vaadin DSL please see the Vaadin Groovy Builder library.

Vaadin 8 No longer maintained

Vaadin 8 support is no longer maintained. If you're still using Vaadin 8, please use Karibu-DSL 1.0.x. Please find the documentation for Karibu-DSL Vaadin 8 in the 1.0.x README.md. Also see Issue #35 for more details.

Why DSL?

Just compare the Kotlin-based CategoriesList with the original Java CategoriesList. Both render the Beverage Buddy: Categories page, yet with Kotlin DSL:

• The UI structure is immediately visible
• The code is more readable and much shorter and concise
• You can more easily copy parts of the UI and paste it into your project

Supports Vaadin 14+.

Example Projects

Vaadin 24:

• Simple one-page-one-button example app: karibu-helloworld-application (Gradle), karibu-helloworld-application (Maven)
• Two-page app demoing grids and database: Beverage Buddy VoK running on vok; Beverage Buddy JOOQ
• A simple database-backed one-page task list app: vaadin-kotlin-pwa

Vaadin 8 UITest / Component Palette

Back in the days there was a Vaadin 8 project called UITest (or Component Palette) which demoed all Vaadin 8 components along with all of ValoTheme styles. The project is no longer around officially, but there's a karibu-dsl fork of the project. To run it quickly, follow these steps:

git clone https://github.com/mvysny/karibu-dsl
cd karibu-dsl
git checkout 1.0.x
./gradlew clean build example-v8:appRun

You may need JDK 11 or JDK 8 to run the demo: JDK 17+ may or may not work.

Deprecation notes

The NumberRangePopup, DateRangePopup, ClosedInterval, NumberInterval and DateInterval classes have been removed from this project since they were too specific. You can find them in the jdbi-orm-vaadin project.

Testing

Please see the Karibu-Testing library, to learn more about how to test Karibu-DSL apps.

Contributing / Developing

See Contributing.