I have a problem.
I am coding using VS2008.
I am calling webservices from my JavaScript Page.
An example
Services.ChangeDropDownLists.GetNowPlayingMoviesByLocationSVC(
blah,
OnSuccessMoviesByRegion,
OnError,
OnTimeOut
);
after execution, it goes to the function OnSuccessMoviesByRegion.
But if I put the Services in a loop (a simple for loop)
Services.ChangeDropDownLists.GetNowPlayingMoviesByLocationSVC(
blah[i],
OnSuccessMoviesByRegion,
OnError,
OnTimeOut
);
OnSucessMoviesByRegion function won't execute (but the service call executes n times successfully
But I must have the function cos I am returning value through it.
What am I missing?
Is that the typical behaviour?
Any alternatives?
Naveen, I'm answering your follow-up question here. I can think of two options:
Try to make a single call packaging your data (sending the whole blah array and handle it on the server).
Use a counter variable which you decrement in the "OnSucces" client handler each time and stop if this counter variable reaches 0.
I guess there is some kind of concurrency problem. Probably you fire the next request before the last one finished.
I think you'll have to rewrite the loop. Try to move that code, calling only the first request and then using the "OnSuccess" function to call the next one each time.
Related
As this thread, we can stop iteration loop by setting function (f:trainer -> bool) as Trainer's stop_triger.
But in this way, I think we can't use other extension such as LogReport which use stop_trigger=((args.epoch, '10')).
So, my question is how to implement early stopping as the Extension and how to send a signal to stop trainer's iteration from Extension.
thanks.
I implemented the example code on gist,
and updated the answer on the original thread.
I noticed that stop_trigger originally uses tuple notation like (args.epoch, '10'), instead we need to change to pass a callable object (EarlyStoppingTrigger in above example).
I am looking for a way to insert a call to my function or a slot with every looping of the Qt's event loop. I know there exists a solution using QTimers which is prescribed by Qt but they also say it is possible by calling processEvents(). Does that mean that I don't call exec at all and do the following?
while(true)
{
// My processing code
// blah blah
qApp.processEvents();
}
I believe this is not what they meant. Does anyone have more idea on how to do this using the processEvents() approach?
This question is similar to
Executing slot on every application's event loop iteration
but I am looking for something completely without timers.
Any references or links are very much appreciated.
Best,
CV
while trying to solve my problems in serializing the execution of cairngorm commands, I tried to bypass completely the event dispatching and simply instantiated the command I wanted to execute, then called it's execute method. In this method there's a call to a delegate that calls ServiceUtils that performs the HTTPService.send thing...
Now, those commands should be run in the exact order I call them.
And, since the server (RAILS) is only one, all requests should return in the same order.
This isn't so.. the order varies upon different executions.. why?!?
Just because you send requests in a certain order doesn't mean the responses will return in that order. HTTPService calls are asynchronous. For example, assume the following three requests are sent at the same time:
Request 1 (takes 4 seconds on the server to process)
Request 2 (takes 0.5 seconds to process)
Request 3 (takes 2 seconds to process)
Assuming network speed is constant (and a lot of other environment issues being constant), you will get the response for Request 2 back first, then Request 3, then Request 1.
If you need to call them in serial, you should do something like this:
protected function doWork():void {
request1.send();
}
protected function onRequest1Complete(e:ResultEvent):void {
request2.send();
}
protected function onRequest2Complete(e:ResultEvent):void {
request3.send();
}
protected function onRequest3Complete(e:ResultEvent):void {
// you are done at this point
}
...
<mx:HTTPService id="request1" url="http://example.com/service1" result="onRequest1Complete(event)" />
<mx:HTTPService id="request2" url="http://example.com/service2" result="onRequest2Complete(event)" />
<mx:HTTPService id="request3" url="http://example.com/service3" result="onRequest3Complete(event)" />
Hope that helps.
RJ's answer covers it very well. Just to add to it:
Your commands will create asynchronous requests via the services you use. If you want to "simulate" synchronous execution of commands, the subsequent command will have to be executed in the resultHandler of the previous commands request.
Although this may not always be the cleanest way of doing things, it may be suitable for your scenario. I'll need more information about the nature of service calls and the app in general to make a call whether this is the best method for you or not.
HTH,
Sri
Is there any way to make multiple requests to the callback function in asp.net when using the ICallbackEventHandler? I need the results for each result, however, when I iterate through and call the function, I get the result only for the last call. Any way to make it return a result for each call?
This is what I am passing in via javascript:
function NoPostback() {
$(".spans").each(function(index, item) {
CallServer($(item).attr("myattr"));
});
}
In this, myattr is a custom attribute that holds a value (1..10). What I want returned is something like ('you said: ' + id) to be returned for each of the calls, so that I can go ahead and place them in the appropriate holders.
However, only one item is returned which is the final call made. For instance if there are 4 items, it returns only ('you said: 4').
Any idea on how to have all of them returned?
Thanks in advance.
Most Javascript AJAX frameworks either abort any subsequent requests if one is in progress, or they ignore previous requests and only handle the latest. The AJAX request itself will pass through the browser's XmlHttpRequest object, but the rest of the javascript code is running within the pages thread. Currently, there is no concurrent programming with javascript (however this is slated to change.)
Is there a way to make synchronous calls using RemoteObject in Flex?
All IO in Flex is asynchronous. The typical pattern to deal with this is to use an AsyncResponder. For instance:
var t:AsyncToken = remoteObject.methodCall();
t.addResponder(new AsyncResponder(resultEvent, faultEvent));
think twice when u want it to be synchronous.
Do u know what synchronous mean? it will FREEZE your application until it receive data. Unless u are pretty sure that your remote calling can receive return value immediately (super fast network connection).
if your function call depends on each other, i would suggest you implement a state machine. e.g.
after 1st async call, your state becomes STATE_1, and your next function call will check on this state variable, to decide next move (ignore the current call or carry on).
my 2 cents.
If you want synchronous behavior, just add a wait after you make the call.
EDIT: I've added code for the chaining behavior I was talking about. Just replace the result handler each subsequent time you call the remoteObject.
...
remoteObject.function1(...);
...
private var resultHandler1(event:ResultEvent):void
{
...
remoteObject.removeEventListener(resultHandler1);
remoteObject.addEventListener(ResultEvent.RESULT, resultHandler2);
remoteObject.function2(...);
}
private var resultHandler2(event:ResultEvent):void
{
...
}
I achieved the same in two ways: First, as said above the use of state machines. It may get tricky at times. Second, the use of command queues - I think this is the best way to do it... but the downside is that the UI may not be very reflective in this time.
you should perhaps try and make one request with with all the data u want to be recieved synchronous and then make the different classes that need data listen to the correct data for that class.
ex:
// request
remoteobject.GetData();
// on received request
private function receivedData(evt:ResultEvent):void
{
for each (var resultobject:ResultObjectVO in evt.result)
{
var eventModel:Object;
var event:DataEvents = new DataEvents(resultobject.ResultType);
event.data = eventModel;
eventdispatcher.dispatchEvent(event);
}
}
Something like this. Hopes this helps.
No, why would you wish to do that anyway.
Flex makes things asynchronous so that the user isn't forced to sit and wait while data is coming back.
It would be a very poor user expereince if each time an app requested data the user had to wait on it coming back before anything else could happen.
from comment
No you don't need synchronus behaivour. If you're making say 2 calls and call 2 comes in before call 1, but 2 relies on the data inside 1 then you're left with either don't fire off event 2 till 1 comes back (this will slow down your app - much like synchronus events) or implement a way to check that event 1 has come back in event 2's handler (there are many ways you could do this).
If you're firing off many events then why not have a wrapper class of some description that tracks your events and doesn't do anything on the responses until all events are back.
You can use the AsyncToken to keep track of individual requests, so if you are firing of loads at once then you can find out exaclty whats come back and whats not.
You all are somehow mistaken or not using flex from adobe, if you send 2 calls to the server, no matter if each has an individual resquestObject the second one will ONLY be returned after the first one finish, even if the second one takes 1 milisecond to process. Just try the fibonnaci 1/40 example.
Maybe if you call a synchronous XMLHttpRequest calling JavaScript on Flex, you can do this.