Alex, smslib is distributed under ALv2, which is great. I didn't check
yet if it's OSGi ready, we're looking for that too. All our components
are now OSGi ready. If smslib isn't we'll try to work with them to make
it OSGi ready or find another solution.
The question I have for you is how to you envision the unit testing for
this component? Is there a way to have a mock service provider? We
obviously cannot afford using a real service for the unit tests.
Cheers,
Hadrian
On 01/26/2012 09:21 AM, Alex Anderson wrote:
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?
--
Hadrian Zbarcea
Principal Software Architect
Talend, Inc
http://coders.talend.com/
http://camelbot.blogspot.com/
