002_0004 - AvoidInheritanceFromNonSystem

Inherit from non System module is discouraged

Instead of inheritance, just use separate objects which are associated to the main object. As an alternative, you can add the child’s attributes to the super entity and add an ObjectType enumeration.

Metadata

authors:
- Xiwen Cheng <x@cinaq.com>
category: Performance
input: '*/DomainModels$DomainModel.yaml'
rulename: AvoidInheritanceFromNonSystem
rulenumber: '002_0004'
scope: package
severity: MEDIUM

Description

Inheritance, except from system module, is strongly discouraged because of the negative performance side effects.

Remediation

Instead of inheritance, just use separate objects which are associated to the main object. As an alternative, you can add the child’s attributes to the super entity and add an ObjectType enumeration.

Test cases

package app.mendix.domain_model.inherit_from_non_system
import rego.v1


# Test data
entity_negative = {
    "Name": "Entity1",
    "MaybeGeneralization": {
        "Type": "DomainModels$Generalization",
        "Generalization": "System.FileDocument"
    }
}

entity_positive = {
    "Name": "Entity2",
    "MaybeGeneralization": {
        "Type": "DomainModels$Generalization",
        "Generalization": "Administration.Account"
    }
}


entities_mixed = [entity_negative, entity_positive]


# Test cases
test_no_entities if {
    allow with input as {"Entities": null}
}

test_entity_negative if {
    allow with input as {"Entities": [entity_negative]}
}

test_entity_positive if {
    not allow with input as {"Entities": [entity_positive]}
}

test_entities_mixed if {
    not allow with input as {"Entities": entities_mixed}
}