I do like this approach - that's what I do when I code using AsyncTokens. In the SDK's trunk depot, we have implemented a different way of using the AsyncTokens which makes it easier to add per-call event listeners and result objects particularly from MXML. It is in the class mx.rpc.CallResponder. Here's a sample of how you'd use it:
<mx:CallResponder id="myResponder" result="optionalEventHandler(event)"
fault="optionalFaultHandler(event)"/>
<mx:Button click="myResponder.token = myService.getAllEmployees()"/>
<mx:DataGrid dataProvider="{myResponder.lastResult}"/>
Each CallResponder monitors a single AsyncToken at a time and propagates its
result and fault events to listeners on the call responder. It also stores the
lastResult property. This allows you to cache the previous result while the
next call is in progress. Any feedback folks have on this approach will be
appreciated.
I'll admit that modifying the token after the call was made is
counter-intuitive. It works because the AS VM cannot deliver any events on
that token until after the current executing code path has completed. We did
consider passing in the token as an argument to the async calls but didn't
think it really made things easier to understand and adds a risk that you'll
use the same token for two simultaneous calls.
Jeff
From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of
lagos_tout
Sent: Friday, October 17, 2008 10:33 AM
To: [email protected]
Subject: [flexcoders] Re: Reusing HTTPService
I like! This line says it all:
> service.send().addResponder(new MyIResponder(resultB, faultB));
Thanks much. I think this is the solution.
It meets my requirements: no long conditionals; one-to-one matching of
service calls to fault/result handlers; reuse of the same service
object; and, if i create a separate class (implemementing IResponder
and containing it's own fault and result handlers, rather than passing
it in as you've done) for each type of service call, i think i get to
live another day by the OO mantra "closed to modification, open to
extension".
Weird though how Flex requires one to add the responder after the call
is already made, don't you think? One would think the responder
should be in place before the call to service.send().
Thanks again!
LT
--- In [email protected]<mailto:flexcoders%40yahoogroups.com>, shaun
<[EMAIL PROTECTED]> wrote:
>
>
> How about something like this:
>
> (note: I've not tried it, just slapped it straight into the email)
>
> public class MyClassThatInvokesHTTPServices {
>
> //inner helper class.
> class MyIResponder implements IResponder{
> public var f:Function;
> public var r:Function;
>
> public MyIResponder(r:Function, f:Function){
> this.r = r;
> this.f = f;
> }
>
> public function fault(info:Object):void {
> f.call(info);
> }
>
> public function result(result:Object):void {
> r.call(result);
> }
> }
>
> //Your handlers for service calls.
> protected function resultA(result:Object){ ... }
> protected function faultA(info:Object){...}
> protected function resultB(result:Object){ ... }
> protected function faultB(info:Object){...}
>
> var service:HTTPService ...//assume exists, reused for various
calls.
>
> //send for service A.
> funciton sendA(args:Object){
> service.url = "../A.html";
> service.send(args).addResponder(new MyIResponder(resultA,
faultA));
> }
>
> //send for service B.
> function sendB(){
> service.url = "../B.html";
> service.send().addResponder(new MyIResponder(resultB, faultB));
> }
>
>
> }
>
> [snip]
>
> >>>> --- In [email protected]<mailto:flexcoders%40yahoogroups.com>,
> >>>> "lagos_tout" <lagos.tout@>
> >> wrote:
> >>>>> Hi,
> >>>>>
> >>>>> I'm re-using an instance of HTTPService, changing the request
> >>>>> arguments to get different responses from the server. But I
> >> found
> >>>>> that if, for instance, I made 3 calls this way with the
> >>> HTTPService,
> >>>>> each of the 3 result handlers registered for each call is
> >> executed
> >>>>> every time a result returned.
> >>>>>
> >>>>> I solved this by storing a reference to the unique AsyncToken
> >>> returned
> >>>>> by each service call and matching it to the AsyncToken
> > contained
> >>> in
> >>>>> each ResultEvent's "token" property in order to determine
> > which
> >>> result
> >>>>> handler to execute.
> >>>>>
> >>>>> I'm not terribly happy with this setup. It seems messy. I'd
> >>>>> appreciate any suggestions on how I can reuse an HTTPService
> >>> instance
> >>>>> without ending up with long switch statements with countless
> > "if
> >>>>> thisAsyncToken then do thisHandler, else if thatAsyncToken
> > then
> >> do
> >>>>> thatHandler... and so on".
> >>>>>
> >>>>> Thanks much.
> >>>>>
> >>>>> LT
> >>>>>
> >
> >
> >
> >
>
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