How to process an asynchronous queue from within the main UI thread?

  

I am designing two components that asynchronously receive objects of a custom class (TMELogMessage) and store them in a thread-safe internal container. The first component is non visual (TMEFileLogger) and should write some info from these objects to a log file (non surprisingly). The second component (TMELogGrid) is a visual FMX.Grid descendant that should visualize some info from these objects in the UI. But what they do with these objects is, I think, irrelevant.

The problem I am facing is that these components do not actually know when these objects will be enqueued in their internal container, so they have to check the container themselves to see if there are any new objects that need processing, process them and remove them from the queue. Ideally I’d want this to be done when the application is not too busy, in a way similar to action updating, so as not to bog down the UI.

It is obviously wrong for a component to hook an event handler like Application.OnIdle… I could maybe subscribe to the TIdleMessage, but I’m not sure that is a good idea, as I’ve read that a some applications could never go idle. Using an internal timer seems a bit old-school. I could maybe use a low priority thread to poll the queue and then synchronize with the UI only when I find some object to process. I don’t have other ideas though.

What is the proper way to do this in Delphi + multiplatform FireMonkey?

Comments are closed.