Hello,

Short version : How can I make the code snippet at the bottom of this message
compile and run without a VerificationError ?

Long version

For some Flash 10 project of mine I'm trying to develop a "lockable" ByteArray
class, because I need to pass sensitive binary data to third-party libraries
implementaing my interfaces, and I don't want them to be able to change it.

For that purpose I made a class that extends ByteArray and overrides all
methods that could change the array contents (write*, clear, compress,
decompress, inflate, deflate). I attached a shortened version of it to this
message.

So the code compiles all fine, but the problem comes at run time :
[Q]VerifyError: Error #1053: Illegal override of clear in
org.sprods.security.LockableByteArray.[/Q]

For the sake of testing I commented my override, and I get this at run time
when I try to call clear() :
[Q]ReferenceError: Error #1069: Property clear not found on
org.sprods.security.LockableByteArray and there is no default value.[/Q]

So I thought maybe the compiler sees that i'm extending ByteArray, but the
player doesn't ? And at this point I couldn't come up with any improvement or
workaround to make the class work. I tried to use the AS3 namespace as for when
overriding arrays, removing the override keyword... nothing that both the
compiler and player accepts.

I'm using Flex Builder 3 with the 3.2 framework, with the FP10 swc attached as
an external library.

So of anyone has a solution or a clue, I'd greatly appreciate it.

public class LockableByteArray extends ByteArray
{
private var _locked: Boolean;

public override function clear():void
{
if(_locked)
throw new IllegalOperationError("This byte array is read only");
super.clear();
}
}

I looked at this real quick... and the only thing I can tell you is that Flash
Player 9 ByteArray did not have a clear() method. Flash Player 10 ByteArray
does have a clear() method. I made a simple two code file test, where I'm
extending like you are from a ByteArray and I override the clear() method. When
I publish to fp9/as3 I get the error you have, because fp9 didn't have a
clear() in ByteArray and hence you can't override it. When I change it to fp10,
it compiles and runs just fine. So I would suggest to check that you're really
building a fp10 file. Other than that you have everything right... so somehow I
think your app is publishing to fp9. Hope this helps.

Thanks for having a look. However I should have pointed out some other details :
- I make a heavy use of the Vector<> generic class, which is not included in
fp9 and works fine in my app, where overriding clear doesn't. (which proves I'm
correctly targetting FP10)
- The clear method was just an example here but I have the same problems with
inflate or deflate, which were available in FP9 too.

Well the use of the Vector<> class does prove you're in FP10, but Vector<>
doesn't have a clear() method to override either. It doesn't have a inflate or
deflate either. Not sure what class you were referring to, but Vector<> doesn't
have those methods hence you can't override them. You should check what methods
the core classes have that you can override at
http://help.adobe.com/en_US/AS3LCR/Flash_10.0/
Good luck.

I'm not saying I tried to override Vector. I just use it successfully, which
means I target the FP10 compiler and player as I should (because Vector has
been introduced with FP10). So the problem is not a wrong version problem.
Also, the ByteArray exposes inflate, deflate, that existed in FP9, and displays
the same error messages when I try to override them.

I'm not sure where you're getting that ByteArray has or had a inflate or
deflate... in FP9, because it didn't. It does in FP10, and I can override them
just fine. clear() also overrides just fine for me. When running this is will
print two traces: "byte array created" and "byte array cleared".


package
{
import flash.display.MovieClip;
import MyByteArray;

public class DocClass extends MovieClip
{
public var clip:MovieClip;

public function DocClass()
{
var b:MyByteArray = new MyByteArray();
}
}
};

package
{
import flash.utils.ByteArray;

public class MyByteArray extends ByteArray
{
public function MyByteArray()
{
super();

trace( "byte array created" );

clear();
}

override public function clear():void
{
trace( "byte array cleared" );
}
}
};