Force Garbage Collection in AS3?

Question

Is it possible to programmatically force a full garbage collection run in ActionScript 3.0?

Let\'s say I\'ve created a bunch of Display objects with eventListeners a

Answer 1

I have a comment on those saying you should never do GC manually. I'm used to manual memory management in C++ and I prefer sharedptr a lot over GC, but anyway.

There is a specific case where I can't find another solution than do a GC. Please consider: I have a DataCache class, the way it work is it keeps result objects for certain method calls that send out updated events when refreshing/receiving data. The way the cache is refreshed is I just clean all results from it and send the event which causes any remaining listeners to re-request their data and listeners that went out of scope should not rerequest which cleans out not needed results. But apparently, if I can't force all listeners that still dangle waiting for GC to be cleaned up immediatly before sending out the "ask you data again" event, those dangling listeners will request data again unnecessarily. So since I can't removeEventListener because AS3 doesn't have destructors I can't see another easy solution than forcing a GC to make sure there's no dangling listeners anymore.

(Edit) On top of that I cannot use removeEventListener anyway for binding which were setup in mxml, for example (using my custom DataCacher class which handles remoteobj)

<mx:DataGrid id="mygrid" dataProvider="{DataCacher.instance().result('method').data}" ... />

When the popup window containing this datagrid is closed, you would expect the bindings to be destroyed. Apparently they live on and on. Hmm, shouldn't flex destroy all bindings (meaning eventlisteners) from an object when it's being marked for GC because the last reference is deleted. That would kinda solve the problem for me.

At least that's why I think, I'm still a beginner in Flex so any thoughts would be appreciated.

Answer 2

Yes, it's possible, but it is generally a bad idea. The GC should have a better idea of when is a good time to run than you should, and except for a very specific case, like you just used 500MB of memory and you need to get it back ASAP, you shouldn't call the GC yourself.

In Flash 10, there is a System.gc() method you can call (but please don't, see above) - keep in mind System.gc() only works in the debugging version of Flash player 10+.

In Flash 9, there is an unsupported way to force it via an odd LocalConnection command, but it may not work in all versions. See this post by Grant Skinner.