This strategy/pattern is also known under the name "Synchronizer Token"
or "Deja vu Token". It detects:
-Multiple form submit (doubleclick)
-Browser back button pressed and resubmit
-Browser stop button pressed and resubmit
Time ago i have made a little servlet/jsp-prototype implementig this
pattern. You can find the source here (it's real quick and dirty):
https://svn.intelli.ch/fh/trunk/Diverses/michael/
My question is, doesn't JSF support this already innately? Do i really
to write my own code to detect for example a multiple form submit?
Michael
Adam Winer schrieb:
Sure, what you do is:
- Store a token - Integer, String, enum, anything you want, that
indicates what page you're on, just like you're doing now. As you know,
this will be restore when the back button is hit.
- In addition to storing that token right on the pageFlowScope, also set
it into a one-element array on the pageFlowScope - but don't create a
new array each time, just keep writing into that first element.
The one-element array will *not* be restored to its prior state, because
it's still the same instance. Consequently, when you go back a page,
you'll see that the token directly on the page won't match the token
within the array. Back button detected!
You could encapsulate this strategy into a reusable object if desired.
-- Adam
On 6/11/07, *D. Cardon* < [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Thanks, that clarifies the documentation.
So, my follow-up question would be: Is there any way that I can
detect in Trinidad that the user
has gone from one page to the next one and then back again?
Thank you for your help,
--David
--- Adam Winer < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:
> On 6/8/07, D. Cardon <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
> > Hi *,
> >
> > I'm a little uncertain about how the pageFlowScope interacts
with the browser's Back button.
> The
> > documentation states:
> >
> > "...clicking the Back button will automatically reset the
page flow scope to its original
> > state."
> >
> > Which 'original state' is this referring to?
> >
> > For example, suppose I have this situation:
> >
> > I have a wizard application. On the first page of the wizard,
the user should enter a
> username
> > and password and then proceed to the next page of the wizard.
> >
> > When the first page of the wizard loads, the username and
password fields may be entered into.
> > The page that takes the user to the first wizard page creates a
"mode" variable in the page
> flow
> > scope and sets it to "create".
> >
> > After entering valid information, the user presses the "next"
button on the wizard. In
> processing
> > the command button, the code sets the page flow scope variable
"mode" to "wizard".
> >
> > When on the second page of the wizard, the user then presses
the "back" button. What is the
> value
> > of the "mode" variable in the page flow scope? "create" or
"wizard"?
>
> It's "create".
>
> -- Adam
>
> >
> > I would like to prevent the user from re-entering the username
and password after browsing
> "back"
> > to the first page of the wizard. I thought I could use the
pageFlowScope to do that, but
> maybe
> > there is a better way. Any suggestions?
> >
> > Thanks,
> >
> > --David
> >
> >
> >
> >
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