Creating an external implementation (deprecated)

Create an external implementation when you want to reuse an existing external application or create an external application to handle one or more steps in your process.

1. Open the desktop Process Designer (deprecated).
2. Open a process application in the Designer view.
3. Click the plus sign next to Implementation and select External Implementation from the list of components.
4. Supply a descriptive name for the new external implementation.
5. Click Finish.
6. In the Common section of External Implementation, optionally provide a description in the Documentation text box.
7. In the Custom Properties section, specify the properties to identify and run the external application.
   • For example, for an external Eclipse RCP application, you might add custom properties to pass the Java class name of the form to use for an activity or an application-specific identifier to look up the implementation by another means. Alternatively, you might use the external application name or system ID to find the implementation.
   • You can create parameters with a special meaning. For example, suppose you need to pass a URL address as a custom property. In the Custom Properties section, you could use url as the name and then add a value that is the URL itself (http://mysite.com...).
   • You can also use this section to pass data to variables in a client that were instantiated with a constructor.

   Note: You can add custom properties to pass static metadata about the implementation to the external application. For dynamic data, which would be different for each process instance or environment, use the Parameter Details section as outlined in the following step.
8. Required for Process Portal: In the URL section, specify the URL template for the external implementation.
   When a user opens a task in Process Portal, the URL template is used to call the appropriate external implementation. To include runtime information, such as the task local and environment context, use replacement variables that are surrounded by curly brackets in the URL Template text. Process Portal automatically appends the REST URL to the restUrlPrefix parameter to indicate where task related operations can be performed.

   Tip: To ensure that the external implementation can identify the current task, it is a good idea to include the task ID in the URL template. For example,

   /MyExternalApp/ExternalImpl.jsp?taskId={tw.system.task_id}&lastName={tw.local.lastName}

9. In the Parameters section, add the parameters for the external implementation by clicking Add Input or Add Output.
   For example, if the external implementation provides an interface in which a manager can either approve or reject an expense report, it might include input parameters for the expense report data and output parameters for the decision that the manager makes and the justification for his decision. Be sure to account for all process data that the external implementation requires to complete successfully and also for any data required from the external activity by subsequent activities.
10. In the Ajax Services section, specify the Ajax services that your external implementation is authorized to call.
    Click Add and, from the list of available Ajax services, select the services that can be called from your external implementation. If no Ajax services are available for selection, you can click the plus sign (+) next to User Interface > Ajax Service to create one. See Building an Ajax service.
11. Use Authorize Ajax Services to authorize the Ajax services that can be called from this external implementation. You have the following options:
    • If there are services listed in the Ajax Services list, select Authorize Ajax Services to enable an authorization check be run on the listed services at run time. Only the listed Ajax services are authorized for the call.
    • If the Ajax Services list is empty and you select the check box, no Ajax service is authorized for the call.
    • If you clear the check box, you disable the runtime authorization check and allow this external implementation to call any Ajax service.
12. Click Save in the main toolbar.