Wsld file for service description ?

Question

We are planning for web service to provide our information to third parties , to describe to third parties what our web services will provide do I need wsdl file ? We will start development on web services some time mid next year ,
and now I must tell the tell parties what all information our services will provide , just to tell what my services can provide , should I create a wsdl file ? I know little about web services , but I know wsdl file contains service name parameters etc which I cannot have till I start the developnment , please suggest me what options I have to inform third parties about my service ?

Answer 1

You will have to have at least a design for the service that you intend to provide. It doesn't have to do anything yet but you need to know now what it will do.
In some respects, this is a software development process question. Is the design already solid? Do you have a well defined interface to your service in the documentation? Or is this like every company I've ever worked for - you have a basic idea what the service will do but you don't know the details? The fact that you know that you're not going to implement for 6+ months tends to imply that you do have some software development processes in place. If so, you should know the design already.
So, after you've figured out what your design is I would write some skeleton code and let JAX-WS generate the WSDL based on that. This forms the basis for your implementation.
However, if you only have a general idea of what the service will do then you're in a very tough situation. Your only hope is to provide a versioning capability in your service so that you can accept messages in multiple formats. This allows you to move forward with development while the third parties catch up to the current version. This makes your QA process a real beast as you must test for any supported format. Additionally, you will end up frustrating the third party consumers of your web service as they will get a new WSDL every time you realize that you need to make a change.
Do not fall for the feel good alternative - passing a list of key/value pairs. While easily upgraded with new parameters you'll forever be documenting the keys and values and that is what WSDL should remove.