Cliser: The C++ ServiceThread Class

The Cliser POSIX-threaded Server contains a PoolManager. The PoolManager keeps track of a pool of ServiceThread objects, which are subclassed from PosixThread (see below) and CommunicatorUser.

The ServiceThread class provides the start() function to execute the run() function in a seperate thread. The run() function defaults to calling interactWithClient(), which is implemented in a subclass.

The run() method thus leaves definition of the interactWithClient() up to each subclass. The code generator generates a stub for this method, so that completing the definition of interactWithClient() is about all that must be done to complete a Cliser-generated C++ concurrent (POSIX threaded) server.

The PosixThread (and thus ServiceThread) class provides these operations:

• void isBusy(). Returns true if the thread is busy doing work.
• void run(). This is the code which is to be run in a seperate thread. Defaults to calling interactWithClient()
• void start(). This tells the thread to start running the code in run()

• void interactWithClient(). This pure virtual function is defined by subclasses, and is to perform a service for the client.

When a POSIX Threaded server accepts a new connection, it gets a non-busy thread from the PoolManager. If all the threads are busy, the PoolManager creats a new thread. Next, the thread is assigned a (copy of) the communicator, and is given the start() message. This starts the run() function, which in turn, calls the interactWithClient() function.