Friendly Error Messages and Workflow Control

[tcordova]

I have and advanced workflow I'm working on, and at one point I am moving the document to a child folder. I'd like to check for the existence of the folder before attempting to move the doc and do the following if the folder doesn't exist:

1.  Inform the user with a friendly error message
2.  Stop the task without transitioning to another task.

Help?

[nikhil]

Can you please share your code.

[davidc]

Within the process definition you can use either a decision node or an exception-handler.  You can't display a friendly message, however you can move to a new part of the workflow e.g. assign new task, send e-mail etc

[tcordova]

Can you please share your code.

Here's the action in question:

            <action class="org.alfresco.repo.workflow.jbpm.AlfrescoJavaScript">
               <script>
                  <variable name="dsa_debugMessage" access="write"/>
                  <expression>
                     if (logger.isLoggingEnabled()) logger.log("========== Entering action to set Move Doc to Pending Approval folder in Start State");

                     var dest = bpm_context.childByNamePath("_Pending Approval");
                     if (dest == undefined) {
                        // I want to handle the exception here
                     } else {
                        bpm_package.children[0].move(dest);
                     }
                     dsa_debugMessage = dest;

                     if (logger.isLoggingEnabled()) logger.log("========== Exiting action to set Move Doc to Pending Approval folder in Start State");
                  </expression>
               </script>
            </action>
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How do I code an "exception-handler"?

[tcordova]

Everytime an exception is gnerated, no matter what kind of exception it is, the only message that is displayed back to the user is:

  Please correct the errors below then click Finish.
A system error happened during the operation: Failed to signal transition 'null' from workflow task 'jbpm$230'


Is there no way to at least display the real error, like access denied?

[davidc]

The root cause exception is probably 'access denied' although it's not displayed in the UI.  We need to find a better way to report workflow errors.

However, if you want to control the flow of the process I would use a decision node to test for required state before entering the node that performs the action.  That way, you can explicitly control how to handle issues (e.g. by sending an e-mail, moving to a another task etc).