How Vaadin 7 Works . Overview of vaadin 7

Vaadin 7 is framework to build Rich Internet Application using Java.


Server Side UI

First call by web browser/ refresh of link will call VaadinServlet which will create UI(front end components) and initialize it and sends back UI to response . UI State is maintained per session in VaadinSession.

@PreserveOnRefresh - will preserve client / web browser state on refresh.

Further calls made by user are ajax calls / calls to its own client component which are automatically done by client side engine.

We add various types of event listeners to ui component in server side.

Vaadin Client Engine automatically converts this listeners to java script and rendered it in web browser after returning the response(ajax calls /servlet response made by refresh/first call). Listeners of the event manipulate UI components/ calls server side methods/both. Vaadin automatically identifies UI component and server side calls and make rpc for server side calls.

Widget Set

Widget set are GWT module that we can use it in Server Side Code of Vaadin. Widget Set must be compiled before it can be used.

Themes

Used for styling UI in Vaadin. Vaadin provides various built in theme. We can also create our own theme.

Client Side Application
Vaadin Also supports client side application development similar to GWT

Addons
Various Server Side component/ widget set are available freely which can be used directly in our project.

This is basic about What is Vaadin 7 and How it works. There are lot more features availble. Kindly check its Official Website.