Packet Processing

interface PacketHandler
{
    // ...
}

PacketHandler handlers[] = new PacketHandler[ 128 ];
handlers[ 0 ] = new LoginHandler();
handlers[ 1 ] = new RegisterHandler();
// Etc.

byte id = buffer.readByte(); // Packet ID
if ( id < 0 || handlers[ id ] == null )
{
    // Bad packet ID!
}

handlers[ id ].Process( buffer );