In my last article I showed you how to expose a PowerBuilder component on an EAServer as a Web Service that could then be orchestrated into a Business Process Service in Unwired Orchestrator with Sybase WorkSpace. In this article I want to attack the big picture from another angle, the angle of calling a Business Process Service in Unwired Orchestrator from a PowerBuilder Client.

Business Process Service
What I'll leave out is the area in the middle, the technology for how to use Sybase WorkSpace to orchestrate other services into a Business Process Service. Such a process can contain many things, such as a Database Service, Java Service, and a SOAP Service (see Figure 1). If you want to see how this can be done, see my blog at http://ianthain.pbdjmagazine.com and find the posting for "TechWave 2006 Boot Camp Workbook and Videos." Here you can download everything you need to create the BP in Figure 1.

This Business Process Service uses a Database Service that calls a database Stored Procedure, returning the first and last name of a particular customer id. It then uses the first and last name as input parameters to a Java Service that concatenates the two together but in reverse order as a result. Then the orchestration calls a SOAP Service, which is, in fact, a PowerBuilder component in EAServer exposed as a Web Service, and this returns the current date and time in EAServer. Finally, everything is returned from the Business Process Service as a string (see figure 7).

Once this Business Process Service is created and deployed from Sybase WorkSpace to Unwired Orchestrator on EAServer, its WSDL can be viewed and saved (see Code Listing 1). Short for Web Services Description Language, WSDL is an XML-formatted language used to describe a Web Service's capabilities as collections of communication endpoints capable of exchanging messages.

PowerBuilder Client Application
For the application we'll use the .NET Web Service Engine so make sure that you have.NET 2.0 SDK installed on the client machine before proceeding any farther. This can be downloaded from www.microsoft.com/downloads/details.aspx?
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PowerBuilder 10.5 can help us use SOAP in a 4GL way. Let's face it, we're 4GL PB developers and want to concentrate on solving the bigger business problem at hand quickly rather than getting lost in lower-level technologies. We do this by importing the PB Extension, pbwsclient105.pbx (see Figure 2)

Once imported into the PBL, you'll have two SOAP NVOs that will aid you in calling your Web Service; these are soapconnect and soapexception (see Figure 3). But, this is only part of the way that PowerBuilder helps us. So, next we have to create a Web Service Proxy for us to call the operation (Web Service method) in the Web Service, and we have a wizard available from the New|Project Tab to help us.

In the Web Service Proxy Wizard (see Figure 4) we select the.NET Engine and point the wizard at the previously saved WSDL from our Business Process Service. The wizard can then parse the WSDL and display the available services. Along with this, PowerBuilder automatically generates all the necessary DLLs for the Web Service interaction (see Figure 5) and the necessary PowerBuilder object for you, the developer, to use in your application (see Figure 6). Operation1 was defined when initially creating the Business Process in Sybase WorkSpace, along with the input parameter cust_id, now defined in the structure bpoperation1 and the return parameter result now defined in the structure bpoperation1response.

Now all that's left is to develop the PowerBuilder client application, and for this I've created a very simple SDI (see Figure 7). In the button-clicked event (OK...let's not get drawn into the correctness of putting the code here....It's a test application), we can code the PowerScript to...

1. Create a SOAP Connection
2. Create an instance of the Proxy Object in memory
3. Populate the input parameter
4. Call the Operation in the Business Process Service
5. Display the result