BLE communication refactoring

[monday8am]

Hint for reviewer:

This code works right now. The next topic is to decide where to include it (as part of our lib or as a demo implementation)

• APDU fragmenter: https://github.com/fidesmo/apdu-over-ble-android/blob/descriptor-fix/app/src/main/java/com/fidesmo/ble/client/apdu/SimpleApduFragmenter.java . Just to fragment and defragment packets at APDU level ( a packet could contains more than one apdu)

• Custom defragmenter: https://github.com/fidesmo/apdu-over-ble-android/tree/descriptor-fix/app/src/main/java/com/fidesmo/ble/client/apdu (directory, check files starting with Custom)

• In Android, BLE reads or writes data in small chunks and sometimes this chunk size doesn't fit the MTU defined. That's why an extra logic is needed to start to read a real packet and to completely read it: https://github.com/fidesmo/apdu-over-ble-android/blob/descriptor-fix/app/src/main/java/com/fidesmo/ble/client/BlePeripheralService.java#L251-L255
  or in case of read request:
  https://github.com/fidesmo/apdu-over-ble-android/blob/descriptor-fix/app/src/main/java/com/fidesmo/ble/client/BlePeripheralService.java#L223-L231

[sergkh]

Maybe we can think on how to merge this CustomPacketDefragmenter with original Packet fragmenter/defragmenter interfaces? Some of those methods can be handy there too.

But I have some notes about the interface:

• Method add is not informative, looking at the interface you can't say what it is doing and how it is different from the append. Maybe we can rename both to something like addPacket and addBuffer (or nay other variant)?
• Interface is not consistent: you have Java Bean style getBuffer and simplified complete (which in turn has to be completed maybe?) and empty. IHMO it would be good to choose one naming scheme or append isCompleted or remove get what is better to you.
• Original intent was to not use clear and simply recreate the builder, why do you want to reuse it?
• Github complains about not having newline at the end