I'm working on a Camel component for SMSLib (http://www.smslib.org). This is a Java library for communicating with mobile phones and modems via a serial connection to send and receive SMS messages using the Hayes (AT) command set.
I have a working prototype - you can see the source at https://github.com/frontlinesms/camel-smslib I have some general worries regards best-practice for designing the Endpoint, Consumer and Producer for this component. I've not come across comprehensive documentation for implementing Endpoints etc., and it's hard to know which other components would have a similar model to mine and therefore would be worth delving into the source of. Notes on serial devices ----------------------- * before starting to send or receive messages through a device it must be initialised * initialisation can fail Endpoint -------- Each Endpoint will refer to a serial port, with corresponding URIs, e.g.: * Windows: smslib:COM1 * Linux: smslib:/dev/tty01 When Endpoints are initially created, settings for the port (e.g. baud rate) are passed to it. Later we may want to create endpoints for the same port with different settings, but only if the original endpoint is no longer in use. Consumer -------- There should be a maximum of 1 consumer per endpoint. The serial port must be polled to check for incoming SMS. Rather than storing the SMS within the Smslib service, I would like to pass them immediately upstream to the Consumer's Processor. Producer -------- For my usage, I would like a single Producer per endpoint. This is primarily because when there are no active producers or consumers for an endpoint, the serial connection can be closed to allow its use by other programs. It may be reasonable for other uses to have multiple Producers for the same endpoint. Current status -------------- The endpoint has a Thread (implemented in a class SmslibService) which controls the receiving from the serial connection - every 30 seconds the thread wakes and checks the modem for new incoming messages. This SmslibService keeps a reference to a Producer and a Consumer, and should shut down the serial connection when both Consumer and Producer are stopped. Trying to create more than one Producer or Consumer for an Endpoint will cause an Exception to be thrown. This causes problems when the settings used to create an endpoint initially are bad - there will be an Exception thrown in SmslibProducer.doStart() My Questions ------------ * are there any good resources for writing Endpoints that I should be reading? * does anyone know of any similarly-modelled components whose source might provide guidance? * are there any patterns or base classes that I should obviously be using for my Component, Endpoint, Consumer or Producer implementations? * is there anyone else interested in this component who could cast an eye over the code?
