Lacking true native "Deferred" or "Promised" file drag from JAVA

Question

Hello all,
I have been playing around with the drag and drop APIs for quite some time (about 1.5+ years) and I am having a problem producing functionality similar to dragging network-based files in "Windows Explorer". I am not sure if I have overlooked something or if DnD with the native OS is lacking a huge piece of functionality. I would appreciate hearing people's feedback or experience with similar problems.
First, some background. My company's applications provide remote access to a central storage of digital assets (read "files"). Our client provides a view of the files on the server. We have C++-based applications running on both Windows and the Macintosh are able to drag from our application to the desktops and Explorer windows. However, in these drag operations, they each employ a mechanism to hold-off providing the native OS file data until the drop has successfully completed. The OS in each case provides a "callback" to notify our application that the drop succeeded and that we should go and transfer the files. In this way, we can pay the price of transferring the files locally ONLY when the drop occurs (same thing can be applied to the Clipboard).
However, from what I can tell, the AWT/SWING DnD APIs provide no mechanism to do this type of operation. In order to drag files to the native OS, you must explicitly provide the files BEFORE you initiate the drag operation (or place them on the clipboard). This places doing viable native drag and drop from our JAVA applications in serious jeopardy and is causing a great deal of displeasure from our management who are questioning the "readiness" of JAVA.
Since I can't seem to find a way to accomplish this, I have tried entering enhancement requests (about 8 to date), but I have failed to hear back about a single one. I think that either Sun does not monitor some of their enhancement lists or they do not want to address this heavily-desktop oriented issue (I am not sure if this scenario is even possible on a UNIX machine where most things must be "mounted" locally before they can be viewed -- SMB browsing may be the only exception that comes to mind but I do not know if anyone has done this).
In the meantime, we have attempted to change the workflow of our application. We have provided a JAVA window that mimics the filesystem so that we can get the drop event and provide the illusion of a "deferred" drag. In addition, we have provided and "export" feature that places the file locally afterwhich they may grad anywhere they desire. Both of these solutions are hacks and leave a very bad taste in our user's mouths. We can try to write JNI pieces, however, there are just too many UI locking issues to contend with to ensure a timely release of our software.
Has anyone else run into this before? Can anyone provide a more useful workaround? Is it possible to get this issue looked at from SUN? If SUN is looking at it already, what kind of timeframe are we looking at until a potential solution?
Thank you for your time.
Michael Macaluso

Answer 1

I am curious about the verdict for "deferred" file transfers. I have hit the same wall. I have a JAVA client window that allows the user to browse a network file repository. Most of our clients use a Windows platform, so that is my primary interest. I was hoping to: 1)capture the drop event, 2) request the data from the server, and 3) stream it to a temp file/ or to the destination directory, and 4)allow the file system to transfer the temp file. However, I cannot find any documentation regarding this issue.
So I wanted to swtich tracks and set my transferrable data to represent a file on the central server, but that would require a URL object, and I have failed to set the MIME types correctly for NTFS to recongize the transfer. Sorry I don't have any answers. Any suggestions?