Chapter 1

For protocols such as Bluetooth, which are fast and free, this is too heavyweight. It produces
the oddity that, when playing Battleships over Bluetooth, you don't see a response to your
move until the other player has decided what move to take. That's OK over SMS, but over
Bluetooth it feels odd.
It would be possible to add either another layer, or a fairly compatible modification, to RGCP:
� This could allow responses to be sent immediately, without waiting for a piggyback
packet.
� Given the possibility of an immediate response, requires an immediate response in
some situations and, if one does not arrive, resend automatically.
I have provisionally called this protocol QRGCP (Q = quick), but haven't implemented it.
CRgcpSession could use better construction encapsulation. Rather than providing a C++
constructor to be followed by either ConstructL()or RestoreL(), it would be better to
provide two public NewL()s, one with construct semantics and the other with restore
semantics.
The Battleships Protocol
BSP, the Battleships Protocol, builds on RGCP to allow players to play the two-player game.
Within the span of a single conversation (or 'session'), multiple Battleships games may be
played. Outside a session, you cannot play a game.
A session is set up by one partner initiating and the other listening. Partners specify whether
they want to move first, or move second, or don't care. The decision is arbitrated in favor of
the initiating partner (who will go first if they so requested, or if neither party cares, or if the
other partner asked to go second).
Normal play consists of a sequence of move requests. The game may be finished by being
won by one partner (and therefore lost by the other) or by being abandoned by the player
whose turn it is to move. If the game is finished in either of these ways, the session remains
active and another game can be started. This time, the player who lost or abandoned gets
preference for the first move.
The RGCP session may be terminated, at any time, which of course terminates any game
currently in progress.
Protocol Overview
Here's a brief look at the details of BSP.
States
The possible states of a Battleships application are
State Meaning
Blank No conversation is established. The game is in an arbitrary state (either a
neutral state if the program has just started, or the state at the end of the
last game if a conversation has been terminated).
Initiating You have chosen whom to play against and initiated a conversation with
them. You have also specified your first-move preferences. The game is
initialized to a neutral position.