COBOL considerations specific to COBOL rule subprograms

You have extra things to consider when you choose to generate COBOL rule subprograms as an execution option.

Deprecated feature:

Deprecation icon The COBOL code generation feature is deprecated in V8.5. This feature will be removed in a future release of the product. Use the COBOL Generation Project Migration wizard to migrate your Rules for COBOL project to a zRule Execution Server for z/OS® compatible rule project. See Deprecated features for migration details.

Designing business object models

To define a business object model (BOM), you first generate a XOM from a COBOL copybook, you use the XOM to generate BOM, and then you define methods for the BOM. For COBOL code generation, you must also implement your methods in COBOL.

COBOL consideration	Description	Further information
COBOL methods for BOM classes	You must implement the BOM methods to COBOL.	Implementing BOM methods for COBOL code generation
Method parameter types	When you define methods, you can use only certain types as arguments and return values.	Method parameter types

Orchestrating

You can use ruleflows in your rule project when you choose COBOL code generation, but the ruleflow structures must be compatible with COBOL code execution. The following table lists the limitations that apply to the ruleflow functions you can use.

COBOL consideration	Description	Further information
Rule task ordering	Whichever execution mode you choose, the generated COBOL rule is executed as sequential mode.	Ruleflows and COBOL code generation
Ruleflow elements	You can use most, but not all ruleflow elements.	Ruleflows and COBOL code generation

Authoring

If you intend to generate COBOL code and execute your rules in Enterprise COBOL, you must make sure that the rule authoring features you use are compatible with COBOL code execution.

COBOL consideration	Description	Further information
BAL keywords and features	When you write rules, you must make sure that the BAL keywords and features you use are compatible with COBOL code execution.	BAL keywords and features
Rule and ruleset variables	You can use only certain types for rule variables and ruleset variables. You can change the default mapping for primitive and String types.	Variable mapping for COBOL
Number rounding	You can use the ROUNDED clause to avoid truncation.	Number rounding

Optimizing

You can use the Exit on First Match property to improve decision table performance during rule execution.

COBOL consideration	Description	Further information
`Exit on First Match` property	To improve decision table performance during rule execution, you can set the `Exit on First Match` property. The first matched rule on the decision table executes and the rule execution program exits the decision table without searching the remaining rows.	Improving the performance of the COBOL program decision table