That was my impressin too. Are they trying to erase the boundary between the server and the client? If that's the case it's a terribly misguided thing to do...
Yeah I am trying to find out. They are here at javaone - doing too much UI on the server side does seem like a real mistake for a tool like this. One of the nice things of things like this (and cappaccino) is that the server side becomes freed from worrying about what the client is doing/has open etc...
This is a matter of taste - benefits of the server-driven architecture are: no limits from the server, no GWT recompilation, direct access to server-side API and resources, better security, full Java virtual machine, full tooling and debugging support. Downsides are: more client-server traffic, more data to store in HttpSession.
yes that is what worries me - I like network stuff to be explicit.
There are multiple levels of control: 1) for each UI component you can select to send events immediately to server or alongside the next "packet" sent to server. 2) as we are building on top of GWT - you have the full GWT-based RPC also if you want to do the communication manually.
Indeed. I'd love to use my Java knowledge to write pretty interfaces, but on the server side I'm better off using Python.
Agreed, I definitely feel most comfortable with my Python on server-side, but the UI ability on this thing is beautiful. Too bad... I wish I was at JavaOne so I could ask these guys some questions regarding how easy it is to separate the two components.
Vaadin keeps the application state on the server, but the presentation (HTML) is 100% generated on the client side. Changes in server-side state are serialized and sent to client in compact User Interface Definition Language (UIDL). This is obviously a more secure approach to writing web apps, since the state is safe on the server. So no pre-rendering of UI on the server..
Yeah. Every component has a server side and a client side. Client side has all the rendering stuff in it while the server side has the business logic. That way the functionality can't be hacked as the client side is just responsible of sending input to the server, where all the hard work is done.
You can ask all the questions on your mind on our forums (http://vaadin.com/forum/). You don't need to attend JavaOne to get the hard questions answered.