Requesting new methods for Spry.Utils. Notifier

Question

I'm building a quiz application with Spry that is based on a
frameset. The main DataSet is contained in the frameset page, and
it swaps in different question type templates in a child frame.
Each of these templates creates NestedXMLDataSets and has Spry
Regions.
When re-using the same template twice in a row, IE will throw
a freed script error, because the objects held by the observer in
the main frame are still in memory, but the page they came from is
gone. (Firefox will work if you remove the Nested Data Set from the
observer list, apparently replacing a spry region with itself is
ok. I'm assuming since the new region is identical to the old one,
the newly loaded page occupies the same space in memory as the old
one, so everything just works as if it were 'new'.)
The solution, therefore, is to remove any observers from the
DataSet in the main frame, that live in the templates in the child
frames.
However, since the region is assigned as an observer
automatically, I have no way of knowing which position it occupies
in the observers array, or how to reference it. So, in order to
remove it, I have to access parent.myDS.observers directly, and
remove all observers but the first. (Knowing that the first
observer on the list is one I manually added and need to persist.)
Bascially, what we need is a method to ID and remove regions
from the observer list, in those cases where a region (and page
containing it) are going to be destroyed but the data set it
populates from persists.
e.g. <spry:regionid="foo">
Also, since there are other objects like Nested Data Sets
that automatically get added to the observer list, it would be nice
to be able to inspect the list.
e.g.: myDataSet.getObservers()
Sorry if this doesn't make much sense, I'm on a lack of sleep
and burned out from debugging at the moment. I'd love to help the
Spry team continue to refine the product because I think it's
great, and in practice, for the most part, it's made developing
RIA's such as e-Learning applications that have to rely on static
XML much much easier.

Answer 1

PaulColombo wrote:
> Bascially, what we need is a method to ID and remove
regions from the observer
> list, in those cases where a region (and page containing
it) are going to be
> destroyed but the data set it populates from persists.
> e.g. <spry:regionid="foo">
You don't need to know the index in the observers array to be
able to remove one, you do how ever need to have a reference to the
object doing the observing to be able to remove it. Each data set
inherits the methods of the Notifier object, so your dataset has a
removeObserver method, so pass in the object doing the observation,
like so:
myDataSet.removeObserver(observerObj);
I've not delved too much into the datasets, so with auto
added observers, not quite sure what the observer is that needs to
get removed, but if you can figure it out you can use
removeObserver();
> Also, since there are other objects like Nested Data
Sets that automatically
> get added to the observer list, it would be nice to be
able to inspect the list.
>
> e.g.: myDataSet.getObservers()
You already have direct access to the observers array with
myDataSet.observers, what do you get by having a method rather
direct access? Regardless, you can add that method yourself to the
Notifier object and it'll get automatically added to your datasets:
Spry.Utils.Notifier.prototype.getObservers =
function(observer)
return this.observers;
Danilo Celic
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