Rule events can be added to a process model in one of two ways. They can either be added to the process flow as a process node, or they can be used within an activity to trigger an exception flow.
At any time in a process model when there are certain conditions that need to be met before the process flow proceeds, an intermediate rule event should be used. Once an intermediate rule event is activated, it remains active until the rule evaluates to true.
Configuring a Rule Event
To configure a Rule Event:
- In the Process Modeler, select and drag the Rule Event node from the palette to the canvas.
- Connect it to your process model.
- Double-click the Rule Event node. The Rule Event dialog box displays.
- Type a name for your event.
- Select the Setup tab.
- Select New Condition or New Expression.
With an expression, you can use a Rule Event to monitor global constants and process variables. Each time a global constant or process variable is changed, the rule is reevaluated.
Best Practice: As a best practice, we recommend using conditions rather than expressions whenever possible because conditions consume fewer processing resources and less memory than expressions.
Building a Rule Event condition
To build a Rule Event condition:
- Click New Condition on the toolbar. A row is added to the Rules to Continue Flow list.
- Click the first list box.
- A list of process variables is displayed.
- Select the process variable you want to use as a comparison value.
In the second list box, select the operator you wish to use for the condition. The following options are available:
|To perform this operation…
|not equal to
|less than or equal to
|greater than or equal to
- In the text-entry field, type the value you want to compare against the process variable selected in step two.
Creating an expression
To create an expression:
- Click New Expression from the toolbar. A row is added to the Rules to Continue Flow list, containing a text-entry field and the Expression Editor button.
- Click to display the Expression Editor.
- Select the Rules & Constants tab.
- Select a rule to use from the displayed list - OR - Create a new expression using the process variables and properties listed on the Data tab and the logical functions listed on the Functions tab.
Expressions that are created as a rule must evaluate to true or false. Creating an expression that does not evaluate to true or false causes the expression to be automatically set to false.
- Save the expression for reuse by clicking Save as new expression rule.
- You cannot use the map type in this event. This means you cannot reference a process variable of type map, or construct a map using the a!map() function; otherwise, an error will occur.
- You cannot use a record data type in this event. This means you cannot reference a process variable of type record data type, use a record field reference, or use a record type constructor; otherwise, an error will occur.