[news.eclipse.platform.swt] Re: Dropping Java objects as text

[duongn@xxxxxxxxxx (Duong Nguyen)]

David Huebel wrote:
> Is this true?  I haven't created a new TransferData subclass.  As far as I
> know, MyInternalTransfer could be chosen whenever the drop target requests
> a transfer type that uses a byte array as its "native" form.  The way I
> understand it is that the drag source's MyInternalTransfer instance dragT
> offers up a TransferData instance td, and if the drop target mentions a
> Transfer instance dropT for which dropT.isSupportedType(td) returns true,
> then the drag-and-drop framework will use dragT.javaToNative and
> dropT.nativeToJava.  This can happen even when dragT and dropT are
> instances of different classes, or when dropT is native code in a
> different, non-Eclipse application.  That's why I'm worried about the
> circumstances under which isSupportedType might return true for different

I believe most of your concerns here have been answered in my other reply 
so there's no need to repeat myself.

> types.  It makes sense that byte arrays and strings might be considered
> compatible for DND purposes under some platforms.

Bytes and strings are not compatible for DND -- first they have different 
type ids so they will not be accepted -- isSupportedType will be false. 
Secondly, when bytes are converted to strings we must know the encoding 
(unicode, UTF-16, ASCII) and with the wrong decoding the string can become 
garbage.

Duong