Question

I ve just found a strange error when deserializing from a ByteArray, where Vectors cannot contain types that extend Array: there is a TypeError when they are deserialized.

TypeError: Error #1034: Type Coercion failed: cannot convert []@4b8c42e1 to com.myapp.ArraySubclass.
    at flash.utils::ByteArray/readObject()
    at com.myapp::MyApplication()[/Users/aaaidan/MyApp/com/myapp/MyApplication.as:99]

Here s how:

public class Application extends Sprite {
    public function Application() {
        // register the custom class
        registerClassAlias("MyArraySubclass", MyArraySubclass);        

        // write a vector containing an array subclass to a byte array
        var vec:Vector.<MyArraySubclass> = new Vector.<MyArraySubclass>();
        var arraySubclass:MyArraySubclass = new MyArraySubclass();
        arraySubclass.customProperty = "foo";
        vec.push(arraySubclass);

        var ba:ByteArray = new ByteArray();
        ba.writeObject(arraySubclass);
        ba.position = 0;

        // read it back
        var arraySubclass2:MyArraySubclass = ba.readObject() as MyArraySubclass; // throws TypeError
    }
}

public class MyArraySubclass extends Array {
    public var customProperty:String = "default";
}

It s a pretty specific case, but it seems very odd to me. Anyone have any ideas what s causing it, or how it could be fixed?

Answer 1

well, it seems array serialization is hardcoded. you should definitely post a bug report.

actually the code you posted doesn t throw an error since ba.readObject() as MyArraySubclass is simply null. MyArraySubclass(ba.readObject()) however would.

what you could try to fix it, would be to implement IExternalizable, altough I m not sure it ll work any better.

I guess the problem is that Array is a very very special class in ActionScript (in the sense that in some way it is nothing more than any other dynamic class, but in other ways it s not at all) which leads to a lot of Array-specific code in the VM. Also, a question is, why do you need to subclass Array?

友情链接