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

[David Huebel <davidhuebel@xxxxxxxxxxx>]

My application uses a TreeViewer to let users edit "bookmarks" and organize
them in folders.  When users drag bookmarks and folders within the viewer,
they are transferred as serialized objects using a subclass of
ByteArrayTransfer.  This has been implemented and is working fine.  I want
to be able to drag these same items *out* of the application so an external
text representation can be dropped into other applications.

I'm a bit stuck at this point.  The drop data can't be the external text
representation because it wouldn't be appropriate for internal drops. 
Currently the drop data is a reference to the object itself, which works
fine for internal drops and seems like the right thing to do.  However,
since the drop data isn't the external text representation, I can't use
TextTransfer directly.  

The natural thing to do seems to be to subclass TextTransfer and override
javaToNative, but TextTransfer is designed to prevent subclassing -- it has
no public or protected constructors. 

I think I need to subclass ByteArrayTransfer (or Transfer) and implement
getTypeNames() and getTypeIds() to return the same values as
TextTransfer.getTypeNames() and TextTransfer.getTypeIds().  Where do I get
these values?  I would like to delegate to the TextTransfer
implementations, but they're protected.  I don't see any API in the dnd
package that lets me retrieve the platform-specific names and IDs for
dropping text.

Am I going about this the right way?  What am I missing?  Any tips would be
much appreciated.

Thanks,
David