Hi All, I am exposing my process model as a service.I am able to call

You can do this by adding WEB API that exposes the required data based on the process ID. So the way it would work is that your first call to async web service will return the process ID. Once you get the process ID, you can invoke webAPI with the process ID to get the required data.

If you're on 7.9 Web API is an option, if not you could create a web service for the process model to call, passing out relevant data

@ Sathya I am using 7.8 , how to achieve the same here??

Here is an option. Create a callback parameter in the process model that you have exposed as a web service. When the web service / process model is called, the process model can then report back status along the way, using the callback url parameter. This assumes the process model will make http calls using the out-of-the-box functionality. Also note that if the callback requires authentication (e.g. basic auth), you will have to collect the username and password as PVs. Hope this helps.

One more thing. If the client application cannot expose a service to receive status updates, then you can consider a servlet plugin. The servlet plugin would take the process id (returned from the web service call) and maybe a few other http parameters and then respond. And obviously a username/password to authenticate against appian. See the documentation on servle plugins if you decide to consider this.

@sayedh I would like to know what do you mean by call back parameter in process model

Callback URL is another way to say "a mechanism to communicate back to the calling application".

1. So what kind of an application is going to call your process model (which you have exposed as a web service)?
2. Does the calling application have capability to receive an HTTP call?

In other words, you are building them a web service to start an appian process. If they need updates back to them, you need to establish a mechanism of communication. The easiest is for them to create an http service and give you the endpoint. From there, you would use the http smart node to communicate back to them. If they can't build an http call but insist on having updates on the web service call they made, then there are a number of things you can do.

Tell me more about what you are doing and the capability of the calling application and then I can help you to come up with a solution.