Re: Experiences using event bus

WeakMap and WeakSet aren't iterable, you cannot discover what they contain, you have to know and can only check if it's in the map/set and for a map get its associated value. This is of no use for an event bus wanting to keep weak references to its handlers.

A WeakRef would be the only way, other than implementing explicit reference-counting.

On Saturday, August 29, 2020 at 11:21:03 AM UTC+2, Gordan Krešić wrote:

I would like to ask for any advice/idea on how to use event buses in GWT. So
far I'm using GWT's own com.google.gwt.event.shared.EventBus, but wouldn't
have issues migrating to other implementations.

My concern goes to very cumbersome and error prone handling when to
unregister subscribers to allow them to be garbage collected. I'm aware of
ResettableEventBus, but it doesn't solve problems when I don't have clear
events to unregister whole classes of subscribers (if I'm not mistaken, it
was designed to be used inside single Activity and unregister all
subscribers when activity stops, but that flow doesn't work for me, because
I need subscribers active even when they are not in current activity).

When possible, I'm subscribing to events in "onLoad" event and unsubscribing
in "onUnload", but that also doesn't work in not-that-uncommon corner cases
when I need subscribers active even when detached from DOM.

Only "solution" that works is manually unregistering when I'm sure
subscriber is going away, but as I said, that is very error prone (and beats
the purpose of having a garbage collected language).

WeakReference(s) are not supported. Is there any implementation trying to
utilize JS's WeakMap?

Any other ideas?

        -gkresic.

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