Re: HowTo use GWT EvenBus to schedule OpenEvent -> CloseEvent sequence

Another example from GWTP https://github.com/ArcBees/GWTP/blob/master/gwtp-core/gwtp-mvp-client/src/main/java/com/gwtplatform/mvp/client/proxy/PlaceManagerImpl.java, as Jens said, having a manager controlling the ordering of the events seems a good idea. And PlaceManager control the ordering of various event fired in the eventBus like FireRequestInternalEvent, LockInteractionEvent and NavigationEvent. LockInteractionEvent is a dual event, one for lock start, and the second for the lock ends, which looks similar to your case.

On Thu, Oct 27, 2016 at 2:22 AM vitrums <vitrums@gmail.com> wrote:

Thank you for quick responses. It seems that we all resorted to Scheduler and control our custom events by tweaking the intrinsic logic of browser's event loop. I thought I could completely miss some obvious solution.

On Wednesday, October 26, 2016 at 7:51:19 PM UTC+3, vitrums wrote:

[ Original post on StackOverflow http://stackoverflow.com/questions/40130383/howto-use-gwt-evenbus-to-schedule-openevent-closeevent-sequence ]

Say we have few handlers for both events. The goal is to make sure, that all OpenEvent handlersfinish before any of CloseEvent handlers start their job. The old EventBus had a reverse order flag, which sometimes helped greatly in these particular cases. I.e. a handler, responsible for launching some process which leads to CloseEvent being fired (i.e. event emitter), usually registers itself to a bus first.

Now, due to a synchronous nature of javascript each handler of OpenEvent ends his job before the next handler starts. In my app the first OpenHandler added to a bus is a CloseEvent emitter. Therefore I get an undesirable sequence of calls: 1st handler of OpenEvent -> all CloseEvent handlers -> the rest of OpenEvent handlers.

My question is: what's the best practice to establish the desirable behavior? So far as a workaround I use Scheduler.scheduleDeferred(Scheduler.ScheduledCommand cmd) to enqueueEventBus.fireEventFromSource(Event event, Object source) of CloseEvent call to the next browser's event loop tick.

p.s. My current thoughts are as follows. I don't want to rely of Timer or Scheduler (though it might be the only option, which I'm not sure about). Also I have no interest in introducing any flag variables, responsible for tracking which event occurred first. Instead, if one looks closer into theSimpleEventBus code, there's a firingDepth counter variable, which only works to delayaddHandler(...) and removeHandler(...) calls. It would be great, if same logic could be applied to order call sequences of handlers for different events.

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