asynchronous UI design with calling webservice

Question

Hello, i am writing web application in Flex (SDK 3.5).
my program sends web service calls asynchronically to the server that gives me data.
I want to handle a case when the user sends a few requests before the answers to the previous requests
were answered. In such a case i want to give the UI only the last request answer.
It is similar to web page where the user clicks many times on a button. how to show only the final
answer?
I have an idea for saving the last request id in my proxy/BusinessDelegate class. and then, check the token id to see if it is identical to the last request id. And then i send the data to the UI to display.
What Do you think about this idea? Does anyone have a better idea?
thanks,

Answer 1

Here's how I handle this kind of situation

private var lastToken:AsyncToken;
public var service:RemoteObject;

public function makeRequest():void
{
    lastToken = service.doSomething();
    lastToken.addResponder(
        new AsyncResponder(handleResult, handleFault, lastToken)
    );
}

public function handleResult(result:Object, requestToken:Object):void
{
    if(requestToken !== lastToken) return;
    else
    {
        // handle result
    }
}

public function handleFault(fault:Object, requestToken:Object):void
{
    if(requestToken !== lastToken) return;
    else
    {
        // handle fault
    }
}

Answer 2

I think your idea is the right approach, because that's the way it is! :-)

I do it similarly like in Ryan's in answer and I think you idea has the same direction. The Flex RPC classes use the same approach with the lastResult property.