Using java.nio SocketChannel design for games

[vydias]

I've changed all of my network communications over to the new java.nio API greatly improving network speed, memory usaged and performance by using ByteBuffer and SocketChannels and ServerSocketChannels, and the new Non-blocking i/o.  

My problem is that while ServerSocketChannel connection requests allow me to process all reads and writes without using multiple threading (big improvement), I would like to get the same improvements for those players in our game that actually start the connection with a SocketChannel.  

Say we have 20 players already logged in and they all need to communicate then the last player that logged in. I will need to create SocketChannel connections to each of those 20 players.  If this is done I don't see a way to handle the reading from these channels without implementing a threaded listener on each channel. Is there a way to pool these SocketChannels like you can the ServerSocketChannel and have one thread listening for data coming from any/all of them?

None of the examples out there seem to address this issue. Without this ability I'm only able to cut my thread usage down by half rather then simply having 1 or at most 2 threads handling TCP communications for our game. Anyone have code that accomplishes all network i/o with one thread?

[vydias]

btw this is a p2p networking paradigm so we can't have a central server for this part of our game communications. Thus I need to handle multiple SocketChannel connections when logging into the game for communications that is non-UDP capable. Meaning if I'm In TCP mode (firewalled, router non-portforwarding) or another peer is in TCP mode, direct connections must be established from the TCP mode player to the non-TCP mode player. If both parties are in TCP mode then we use a single RELAY server (all TCP players must connect to it) because direct connections can not be made between the two TCP players.

Just a little info on our networking so that people understand why we need to scale back our thread usage and why we have to use TCP connections.