Chapter 4. Creating guided rule templates

Procedure

1. In the guided rule templates designer, click the plus icon ( ) on the right side of the WHEN section.

   The Add a condition to the rule window with the available condition elements opens.

   Figure 4.2. Add a condition to the rule

   

   The list includes the data objects from the Data Objects tab of the guided rule templates designer, any DSL objects defined for the package, and the following standard options:

   • The following does not exist: Use this to specify facts and constraints that must not exist.
   • The following exists: Use this to specify facts and constraints that must exist. This option is triggered on only the first match, not subsequent matches.
   • Any of the following are true: Use this to list any facts or constraints that must be true.
   • From: Use this to define a From conditional element for the rule.
   • From Accumulate: Use this to define an Accumulate conditional element for the rule.
   • From Collect: Use this to define a Collect conditional element for the rule.
   • From Entry Point: Use this to define an Entry Point for the pattern.
   • Free form DRL: Use this to insert a free-form DRL field where you can define condition elements freely, without the guided rules designer. For template keys in free form DRL, use the format @{key}.
2. Choose a condition element (for example, Customer) and click Ok.

3. Click the condition element in the guided rule templates designer and use the Modify constraints for Customer window to add a restriction on a field, apply multiple field constraints, add a new formula style expression, apply an expression editor, or set a variable name.

   Figure 4.3. Modify a condition

   
   Note

   A variable name enables you to identify a fact or field in other constructs within the guided rule. For example, you could set the variable of Customer to c and then reference c in a separate Applicant constraint that specifies that the Customer is the Applicant.

   c : Customer()
   Applicant( this == c )

   After you select a constraint, the window closes automatically.

4. Choose an operator for the restriction (for example, equal to) from the drop-down menu next to the added restriction.
5. Click the edit icon ( ) to define the field value.
6. Select Template key and add a template key in the format $key if this value varies among the rules that are based on this template. This allows the field value to be interchanged with actual values that you define in the corresponding data table to generate different rules from the same template. For field values that do not vary among the rules and are part of the rule template, you can use any other value type.

7. To apply multiple field constraints, click the condition and in the Modify constraints for Customer window, select All of(And) or Any of(Or) from the Multiple field constraint drop-down menu.

   Figure 4.4. Add multiple field constraints

   
8. Click the constraint in the guided rule templates designer and further define the field values.
9. After you define all condition elements, click Save in the guided rule templates designer to save your work.

Procedure

1. In the guided rule templates designer, click the plus icon ( ) on the right side of the THEN section.

   The Add a new action window with the available action elements opens.

   Figure 4.5. Add a new action to the rule

   

   The list includes insertion and modification options based on the data objects in the Data Objects tab of the guided rule templates designer, and on any DSL objects defined for the package:

   • Insert fact: Use this to insert a fact and define resulting fields and values for the fact.
   • Logically Insert fact: Use this to insert a fact logically into the process engine and define resulting fields and values for the fact. The Red Hat Process Automation Manager process engine is responsible for logical decisions on insertions and retractions of facts. After regular or stated insertions, facts have to be retracted explicitly. After logical insertions, facts are automatically retracted when the conditions that originally asserted the facts are no longer true.
   • Add free form DRL: Use this to insert a free-form DRL field where you can define condition elements freely, without the guided rules designer. For template keys in free form DRL, use the format @{key}.
2. Choose an action element (for example, Logically Insert fact RecurringPayment) and click Ok.

3. Click the action element in the guided rule templates designer and use the Add a field window to select a field.

   Figure 4.6. Add a field

   

   After you select a field, the window closes automatically.

4. Click the edit icon ( ) to define the field value.
5. Select Template key and add a template key in the format $key if this value varies among the rules that are based on this template. This allows the field value to be interchanged with actual values that you define in the corresponding data table to generate different rules from the same template. For field values that do not vary among the rules and are part of the rule template, you can use any other value type.
6. After you define all action elements, click Save in the guided rule templates designer to save your work.

Procedure

1. In the rule designer, click (show options…​) under the THEN section.
2. Click the plus icon ( ) on the right side of the window to add options.

3. Select an option to be added to the rule:

   • Metadata: Enter a metadata label and click the plus icon ( ). Then enter any needed data in the field provided in the rule designer.
   • Attribute: Select from the list of rule attributes. Then further define the value in the field or option displayed in the rule designer.

   • Freeze areas for editing: Select Conditions or Actions to restrict the area from being modified in the rule designer.

     Figure 4.7. Rule options

     
4. Click Save in the rule designer to save your work.