RE: $ctxid when and why?

Hi Andras,

Just to followup on Jake's explanation with a little bit of further
clarification. The basic idea of the local context repository, as well as
statemap context associated with the events it that this space only lasts
the duration of the req-resp cycle. There are occasions however, where you
fire a ClientSideRedirectException from within a control handler - in this
case, the single req-resp cycle really gets broken out into 2 cycles: the
first to redirect the browser URL, the second to actually generate the
appropriate view. From the developers perspective, you really want this to
be viewed as one contiguous cycle, even though its physically smanning two
requests...that is really more of an incidental implementation detail
required by HTTP. So that's why its implemented as it is. You don't need to
worry about objects placed in this state context not getting cleaned up.

In the near future, I think I will probably be adding support to optionally
allow events to say "make this event contiguous with the one that comes
after" (thus keeping the local context around in these occasions). Here's an
example of where you might use this - when a user fires a "DeleteRecord"
control event, you first make sure they're authroized to do so in the
handler, etc, and then you may want to actually delete the record and
display the appropriate response. Between the Control and the View events,
however, you may first want to prompt the user "are you sure?"
(y/n/cancel)...in cases like this it might be nice to persist local context
across multiple req-resp cycles.

Hope that sheds some light on the issue...

Christian

----------------------------------------------
Christian Cryder [[email protected]]
Internet Architect, ATMReports.com
Barracuda - http://barracudamvc.org
----------------------------------------------
"Coffee? I could quit anytime, just not today"

  -----Original Message-----
  From: [email protected]
[mailto:[email protected]]On Behalf Of Jacob Kjome
  Sent: Friday, March 21, 2003 12:07 PM
  To: [email protected]
  Subject: Re: [Barracuda] $ctxid when and why?



  See persistContext() and restoreContext() in DefaultEventContext.java....

      //csc_082302.2 - rewritten to persist context using a unique id (per
request)
      //in a Global Weak Repository, rather than persisting context in user
session,
      //which inherantly had problems if multiple frames on a client were
firing
      //different events at the same time. The down side of this fix is that
the
      //redirected url shows in the browser with something like this tacked
onto
      //the url: $ctxid=_1030135624563


  Jake

  At 04:36 PM 3/21/2003 +0200, you wrote:

        Hi barracudas,

    I want you to ask about the $ctxid parameter. As i see this is used to
    persist the event context in more than request-response cyles.
    I don't understand why this is needed.
    My understanding of the EventContext is that it should be used to pass
    objects
     from Control Event Handlers to View Event Handlers.
    These objects would be distroyed when the request-response cycle has
ended.
    My assumption is correct?
    I would be surpised to find out that the Objects put in the EventContext
not
    getting released
    and garbage collected.
    I just found out that throwing a ClientSideRedirectException to a static
    html page would
    look like this: ourpage.html?$ctxid=_5523212233
    How can i disable the persist of the context?

    Thank you,

    Andras.



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