Vaadin Flow 1.0.0.beta12 is a prerelease version for evaluating the enhancements mentioned below. With subsequent beta releases we may change things based on your feedback, and that may lead to API breaking changes.

Vaadin Flow 1.0.0.beta12

Flow is a new Java web framework for creating UIs using Java or HTML. Flow handles everything related to communication between and client and server and makes it possible to create UIs using the desired abstraction level you choose. It has all the capabilities you need to build a modern web app: from high level APIs for structuring your applications and binding data to it, into taking full control over the DOM and communication with HTML templates.

Flow is a part of the Vaadin platform. For information and helpful resources like documentation and examples on Vaadin Flow, please visit the Flow page vaadin.com/flow.

Enhancements in the new Prerelease

• #4061
  Improve keyboard events by converting Key to a functional interface and adding static instances (Thank you @heruan)
• #3387
  Add PropertyDescriptor with a default value of type Double (Thank you @eriklumme)
• #4139
  With Binder, mark field as required only if empty value would fail validation
• #4135
  Maven plugin: allow configuring Yarn's network concurrency argument

Bug Fixes since Previous Prerelease

• #4126
  Updating int values in TemplateModel from client-side
• #4116
  Flow apps not opening inside iOS Safari WKWebView (when eg. following a link from Linkedin or Facebook app)
• #4141, #4142
  Serialization bugs

Breaking changes introduced in the newest Prerelease

• #4148, #4145
  More classes are now Serializable

The complete documentation can be found here

See complete list of changes since previous beta version

Supported Technologies

See the Vaadin platform release notes for browser, server and Java support level.

Known Limitations

• Template-in-Template feature has some limitations
• There is no CDI support #456
• There is no Portal/OSGi support #455

Flow 1.0 Feature Highlights

Using Components to build UIs with only Java

With Flow you to can compose UIs using only Java on the server side. You can use existing components or create your own by creating the DOM from the server side. See the relevant documentation:

• Using Vaadin Components
• Creating New Components and the Element API

Integrating Web Components

Flow allows you to integrate web components and consume them from server side Java. See the web components documentation for more information.

Router

Router is a core concept in Flow, enabling navigation for your website or web app. It is based on HTML5 History API, and makes it possible to for the user to navigate pages back and forward, and keep the page state intact. See the router documentation for more information.

Binding Data to Components

Flow allows you to easily bind your business data to the UI components. You can bind the forms to the business objects by using the Binder, see documentation for more information. For showing a list of data (eg. a database table) on the UI, you can use the DataProvider. See documentation for more information.

Creating UIs Declaratively with Polymer Templates

With Flow you can take full control of building the DOM and the communication by using HTML templates. We recommend using Polymer templates as they bring lots of helpful capabilities on top of the native HTML. See documentation for more information.

Theming Applications

Flow has support for customizing the look and feel of your applications with css, html custom styles or by customizing the ready made Themes provided for Vaadin Components. See the documentation for more information.

Spring Integration

Flow comes with a Spring integration, and you can use it with Spring 5 or Spring Boot 2. Please see the documentation for more information.

Getting Started

For getting started with Vaadin Flow, please see vaadin.com/start where there are three types of examples available:

• Bakery App Starter for Flow and Spring - a full stack example application with Flow and Spring Boot with heavy focus on great UX
• Beverage Buddy App Starter for Flow - a small example app that highlights the basic features of Flow
• Project Base for Flow and Project Base for Flow and Spring
  • A base for your project with some placeholder files available and dependencies available
    All the starters bring the Flow dependency via the Vaadin platform, which is the recommended way for using Flow.

From Flow getting started documentation you can find a step-by-step tutorial.