This is a severe bug in MyFaces. Not only in MyFaces, but it was also in the RI for JSF Version 1.1.
Since 1.1, the bug has been resolved in the RI by providing a map where the state of the application is saved to for the last 20 requests. We should implement something like this as well, there is just no one of the core committers who found the time to do so so far... Would you have the time to cope with this problem? regards, Martin On 9/27/05, Dave <[EMAIL PROTECTED]> wrote: > HI Werner, > Thanks. <x:saveState> does not work in this case. Data saved using > <saveState> are only available to the immediately following request.(post > back in most cases). > > When user click Back, the browser says something like "not available since > previous Form post, ask to refresh ". When use click Refresh, the data saved > using <x:saveState> is not there any more because it is not immediate POST > back. > > Dave > > Werner Punz <[EMAIL PROTECTED]> wrote: > Dave wrote: > > When a backing bean is dependent on some data that are initialized > > by previous page, it works fine normally. But if user click Back/Refresh > > on browser, then the data is not available anymore to the backing bean. > > This will result in NullPointerException because the data is null. How > > to catch this issue and display a nice informative message, definitely > > not Exception? Thanks for ideas. Dave > > > Sorry, my first answer was too short, to clarify things a little bit, > the problem you encounter is due to the request scope, a bean declared > in request scope lives only one request, now if you do a refresh you might > lose > important data along the way, the same goes for back. > > There are various solutions to the problem, the shale token stuff, I yet > have to check out, > but one solution is to use constructs w hich enable scopes bigger than > request. > One solution definitely would be to dump the backend bean into the session > that way non traversed values would survive a refresh. > Another one would be to use a lot of hidden fields, for the non visible data > which has to survive > which is a maintenance nightmare. > > Generally the currently possibly best approach would be to use x:saveState > which stores > beans for every page where a x:saveState tag is hit with the same > declaration, > or to use some kinde of dialog-scoping system: > > Following systems currently are available: > Shale Dialog > Seam > > Seam at least is rather heavy on the configuration side, but it looks like > the most interesting > approach in this area. > Shale Dialog I have not looked into yet, > > the possible most lightweight approach however probably is x:saveState... > > > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mai l has the best spam protection around > http://mail.yahoo.com -- http://www.irian.at Your JSF powerhouse - JSF Trainings in English and German
