Killer Game Programming in Java

Server Activities

The processing done by the server is illustrated in Figures Figure 32-6, 32-7, and 32-8, and is of two types:

• A message arrives and is broadcast to all the other clients.

• A detailsFor message arrives for a specified client and is routed to that client. This is a client-to-client message.

Broadcasting

The most complex broadcasting is triggered by the arrival of a create message at the server.

Figure 32-6 shows how create fits into the overall activity of creating a new sprite. Figure 32-9 expands the "broadcast create and request for details" box in the server swimlane in Figure 32-6.

Figure 32-9. Server activities for a create message

TourServerHandler is principally concerned with differentiating between the messages it receives. TourGroup handles the two modes of client communication: broadcasting or client-to-client. TourGroup maintains an ArrayList of TouristInfo objects, which contain the output streams going to the clients.

When a create n x z message arrives at the TourServerHandler, it's passed to doRequest(), which decides how to process it (by calling sendCreate()):

    private void doRequest(String line, PrintWriter out)
    {
      if (line.startsWith("create"))
        sendCreate(line);
      else if (line.startsWith("detailsFor"))
        sendDetails(line);
      else  // use TourGroup object to broadcast the message
        tg.broadcast(cliAddr, port, userName + " " + line);
    }

sendCreate() extracts the ...