JSF, AJAX and the rendered attribute

Question

If you do JSF AJAX calls and change the component tree while rerendering (or between ajax calls), you'll get exceptions from Mojarra. As I understand it, it's difficult to recreate the component tree partially when the new tree is different as the one stored in the ViewState (or the actual JSF class). That's "ok". I'm thinking about using the rendered attribute and not rendering the component.

My question: How does the rendered attribute work? Does the component get restored and is the component tree, that JSF creates during restore phase, safe? We have a very dynamic XHTML page and not rendering object's instead of disabling them with css classes would really up the speed of the page.

Answer 1

I tried it and it works as expected. So JSF only assumes that the component is there even if it doesn't render anything. Please consider that the view state does get restored and it's still a performance hit (but a smaller one as nothing get's sent over the wire and the output string/html doesn't need to be rendered).