I was recently working on a simple process in PCS for a license approval flow. Given the purists that I am, I began by defining definitions for the various message based activities used in the process flow. The process was an asynchronous process with a few intermediate events. A simplified snippet is shown here for visualization.
In order to implement the above process, I created a service definition (WSDL) with the following schematic. As you can notice, there is a portType for accepting requests into the process (fc.myst.bp.TestDrive) and a callback portType for sending messages out of the process (fc.myst.bp.TestDrive.CallBack). Each of the portTypes have operations for catch and throw messages respectively.
Creating a service definition is considered a best practice as it will not lead to multiple definitions created by the process when generating interfaces from message based implementations. So instead of using “Define Interface” we tend to use “Use Interface“.
If we navigate through the configuration wizard for creating a reference based on an existing service previous uploaded into PCS, we will hit a dead end. Both the portTypes configured in the WSDL will appear under the Callback Port Type drop-down whereas the drop-down under the Port Type combo box will be empty. This will also inhibit creation of the service reference based on the service definition. This is shown in the chain of images below.
In order to resolve this problem, I had a closer look at the interface definition WSDL. Turned out that i had created an abstract WSDL which is perfectly fine given that the composite assembly would just use it to implement an interface and generate a service endpoint from the deployed composite. Tried to re-import the WSDL a few times to see if the issue could be addressed but it persisted.
At last, I changed the WSDL to a concrete definition by adding arbitrary service endpoints to the bindings and re-imported into PCS.
Voila! I was able to create a new reference this time by selecting Use Interface from the start message event with the reimported WSDL.
The source code for the PCS project discussed in this blog can be downloaded from here.