[jsr-314-open] [549-AJAX] Keep server-side state ID for AJAX requests.

[Roger Kitain]

Hey Alexandr,

Thanks for catching this.  I'm adding the following to the
javax.faces.render.ResponseStateManager.writeState method:

     * <p>If the state saving method for this application is {@link
     * javax.faces.application.StateManager#STATE_SAVING_METHOD_SERVER},
     * and the current request is an <code>Ajax</code> request
     * (@link javax.faces.context.PartialViewContext.isAjaxRequest} returns
     * <code>true</code>), use the current view state identifier if it is
     * available (do not generate a new identifier).</p>

-roger

Alexandr Smirnov wrote:
> In the case of server-side state saving, implementation of
> ResponseStateManager saves a new state for an every request,even for a
> same viewId as previous was, and generates a new value for
> "javax.faces.ViewState" hidden field. That feature allows JSF to restore
> proper view state then user returns to previous page by browser "back"
> button and submit some form from that page again.
> But that behaviour is incorrect for AJAX requests because in this case
> browser does not save page in history ( Even if "back" button support
> for AJAX will be implemented, it could be done by special 'iframe'
> object only, and does not save page in history anyway ), and old values
> is only going to garbage. As a result, small view states cache ( which
> default size is 16 ) could be refilled by values from AJAX requests
> soon, and browser "back" button support will be broken.
> Patch to fix that issue have been attached to
> https://javaserverfaces-spec-public.dev.java.net/issues/show_bug.cgi?id=549
>