Hello,
Thank you very much for your input it is very much appreciated, being a
newbie to Web Services it helps me a great deal to have input from
other sources other than text books and web sites. So if you don't
mind I have made a few comments next to your reply so feel free to
comment or correct me wherever you feel is necessary!
I'll try
Background:
I am undertaking a final year project and I have chosen the topic of
Web Services being used to expose some scientific data. This is not the
normal way of going about this, choosing how to implement before any
analysis etc, but I am implementing the service using Java, apache
axis. I am at the stage now where I need to research and select the
appropriate methodology to implement the solution.
First of all, best of luck for your final year project !
My understanding of implementing a Web Service from scratch where there
is no existing data source or application would include the following
steps:
• Initiate the idea for web service
• Analyse and develop a model of the services implementation
• Design each aspect of the Service, from the data source, the
service app, WSDL and so on.
• Develop the data source, service app etc
• Test and Deploy
My points would have been the following :
Analyse data and fonctionnality of the application
Develop the application, taking care of doing good business classes,
that will then be easily ported to Web Services: By that, I mean that
if you want to have let's say, one web service to access the data,
it'll be good to have one class, that will access the data; Later on,
you'll be able to create a Web Service based on the interface of that
class, with the automatic generation tools. ( OR if you want, you can
always do it by hand )
When the application works (tested, deployed) : Design the interfaces
needed for the Web Services ( a package "services" is good to have for
that matter )
Design the Web Services mapping them on that Interface. The classes
generated by the Web Service must just call your business classes, and
nothing else.
Test the Web Services
I have been led to believe that there are various techniques that can
be used along the way to aid the above stages such as SOAD, correct me
if I'm wrong….please! So my original question was a starting point
to aid me with my research.
You probably mean SOA, Service Oriented Architecture ( don't confuse it
with MDA, Model Driven Architecture )
When you say that…..
"Life cycle concerns the
software producing, and when talking about Web Services, you ain't
talking about a piece of software; You are talking about a way to
access your software. That's totally different.
Is the development of the web service as mentioned above a number of
different technologies resulting in a software solution? As there is
nothing in place at the moment and I will be developing a solution to a
problem, using the various technologies and not just accessing
software.
Usually, in Java/J2EE, you produce multi-layered application, to be
able to change the way of presentation and data access. I think it
would be interesting for your project to have this structure in mind,
because you can then argue about the fact that your architecture can be
used for both, a standard app ( webapp ) or even a heavyclient app (
SWING for example ) but you choosed to only interface it *for now* with
Web Services.
Your final comment…
"Besides, most of the time, writing a Web Service is useless, since
there is lot of tools dedicated to that task that will do it directly
from your existing code : you just need an interface to your existing
code, that will then be used to generate the Web Service."
Yes I agree…. I am doing things the hard way and have read about some
of the tools to generate services; maybe this should have been my topic
of research instead. ïŠ
The automatic generation tools, are just helpful; you shouldn't *rely*
on them. I believe that your topic is good, and talking about these
tools is a big plus, but I guess that the main interest in your project
is about how your Web Services can serve a need, and how your
architecture was Web Services ready from the start.
Thanks again for you input, apologies if some of my comments appear to
be poorly informed or seem a little confused it's been a long day and
too much coffee.
Cheers
Chris
I know the coffee and cigarette state pretty good myself, so you don't
need to apologize
Can you make sure to post this on the newsgroup, as I guess it'll be
helpful for some people to read, eventually, and also a good thing for
others to comment.
Cheers,
K
