how to wait for event to finish - apache-flex

Question

I have a child component that dispatches an event in Parent. The event in parent makes a call to our database. Right now, the event gets fired off & the child continues without the results. How do I make it so that the child waits for the results from the database b/f the child continues?
in child:
<fx:Script>
<![CDATA[
dispatchEvent(new Event("getDBcontents")); // dispatch the event in the parent
// do some more stuff here but we need pause until we get the result from the parent
]]>
</fx:Script>
in parent:
public function getDBcontents(event:Event):void {
otherChild.getResult.token = otherChild.childRet.getContents( 'userID.text' );
}

Answer 1

Move the "// do some more stuff here but we need pause until we get the result from the parent" section to a different part. I assume that you are doing a remote call to your database that that has a callback. I'm not sure which mechanism you're using, but let's assume a RemoteObject.
You can pass a function on a custom event that you dispatch. The database section of your code can attach that function pointer to the AsyncToken or just add it to the class instance. Then when it comes back with results you can then call the function that you had passed in as part of the event. The joys of async programming.
I'd recommend looking at the patterns used in Cairngorm and Swiz (Swiz being my preferred framework) as the way they do database calls in those frameworks is exactly what you're trying to do here.
As an example, you could do something like this:
dispatchEvent(new MyCustomEvent("getDBcontents", callBackFunction));
private function callBackFunction(stuffToProcess:Object):void {
//do more stuff here after the stuff is returned
}
//first create MyCustomEvent class extending Event
//Then you need something to handle the event, you can build the event listener yourself, or use something like Swiz to make your life easier
//here is your event handler that you can call yourself, or assign through Swiz Cairngorm
var st:Function;
public myEventHandler(event:MyCustomEvent):void {
st = event.callBackFunction; //your param on your custom function
var token:AsyncToken=this.service.doSomething();
var responder:mx.rpc.Responder=new mx.rpc.Responder(genericResultsHandler, faultHandler);
token.addResponder(responder);
}
genericResultsHandler(result:ResultEvent):void{
if (st != null)
st(result.data);
}