Memory usage and garbage collection of Objects in AS3

Question

I want to know about the Object type specifically when it comes to garbage collection in Flash.

I know that items will be ready for garbage collection in situations like this:

// create
var ar:Array = [];

var mc:MovieClip = new MovieClip();
mc.addEventLisntener(blah, blah);

ar.push(mc);
addChild(mc);

// kill & gc
ar.splice(0, 1);
mc.removeEventListener(blah, blah);
removeChild(mc);

But how/will an Object get garbage collected in situations like below.

Say I have a function in my class MartysMC that I parse an Object through:

package
{
    import flash.display.MovieClip;

    public class MartysMC extends MovieClip
    {
        /**
         * Updates this
         * @param obj An object containing key/value pairs to represent new property values
         */
        public function update(obj:Object):void
        {
            var i:String;
            for(i in obj)
            {
                this[i] = obj[i];
            }
        }
    }
}

And now I make use of this function like so:

var mmc:MartysMC = new MartysMC();

var dataObject:Object =
{
    x: 10,
    y: 34,
    alpha: 0.6
};

mmc.update(dataObject);

What happens to dataObject? Will this get garbage collected from here? Even still, what about the object in this line:

mmc.update({x:15,y:18,name:"marty"});

Answer 1

To see what happen with the GC you can use a Dictionary with a weak reference set to true and using the object you want to cheeck as a key:

var d:Dictionary = new Dictionary(true)
d[myObject] = whatever

when the object will not be longer available it will be delete from the dictionary.

here a complete sample based on your example at wonderfl : http://wonderfl.net/c/e9W4

you see that very quickly both of your object have been garbage collected.