A server derived class application

The previous example set-up the necessary server infrastructure. All that remains to create a real server application is to inherit from ServerBaseClass and override the run(Socket) method.

The Socket parameter is the "pipeline" to the client that has just established a connection. Input (read) and output (write) streams are retrieved from the Socket object. The "protocol" for exchanging data between the server and the client is:

The client writes four integers to the socket
The server reads four integers from the socket
The server "processes" the input to produce an answer
The server returns the answer by writing two integers to the socket
The client reads two integers from the socket
The server waits for the next batch of input from the client

main() gets everything started by creating an instance of the server derived class, and then calling the startServer() method defined in the server base class.

The client application requests a connection on a pre-arranged port number. It then proceeds to play the role reserved for it in the protocol described above.