File transfer with push notification

Hello,

We are using Openfire 3.10.0 and*** Smack API 4.1.1*** to do file transfer on Android.

Are file transfer works fine using the FileTransfer, OutgoingFileTransfer, and InComingFileTransfer classes. Which I think is just peer-to-peer file transfer (correct me if I am wrong).

However, we have a few questions.

  1. Does the smack API using the above classes use peer-to-peer file transfer?

  2. We are wondering is it possible for the sender to send the file to our openfire and then the recipient will download it from our openfire. The recipient will get a notification that there is a file waiting. Instead of peer-to-peer file transfer?

  3. Is it possible that if the receiver is offline, they will receive a notification that there is a file waiting for them to transfer when they go online again?

  4. With the Line application the receiver will receive a thumbnail then they click the thumbnail to download the file?

Many thanks for any suggestions,