Prefer Composition over Inheritance

WarningClean ABAP & Modern Syntax#EC PREF_COMPOSITIONRemote Enabled

Overview

Prefer composition over inheritance.

ATC Finding Message: Prefer composition over inheritance; only CX_* classes should inherit

Rationale

Inheritance creates tight coupling between subclasses and parent implementations, exposes internal state, and complicates refactoring. With the exception of exception hierarchies (CX_* classes) which require inheritance to participate in ABAP error handling, business objects should favor composition by holding references to collaborating classes and delegating tasks.

Non-Compliant

CLASS lcl_order_processor DEFINITION INHERITING FROM lcl_order_validator.
ENDCLASS.

Compliant

CLASS lcl_order_processor DEFINITION.
  PUBLIC SECTION.
    METHODS constructor IMPORTING io_validator TYPE REF TO lif_order_validator.
ENDCLASS.

Configuration & Thresholds

This check can be fine-tuned directly in the ATC Check Variant Editor (CHKV) in Eclipse ADT:

Parameter Name	Data Type	Default Value	Description & Guidance
ALLOW_TEST_CLASSES	Boolean	false	Allow class inheritance inside ABAP Unit test includes

Suppression

To suppress findings for this rule, append the pseudo-comment to the statement:

" Standard pseudo-comment:
... "#EC PREF_COMPOSITION

" SAP CI_ prefix format:
... "#EC CI_PREF_COMPOSITION

Related Rules

• Limit Class Inheritance Depth (Favor Composition over Inheritance) — #EC MAX_INHERIT
• Design for Inheritance or Prohibit It (FINAL) — #EC PREF_FINAL_CLASS
• Prefer NEW #( ) over CREATE OBJECT — #EC PREF_NEW_OPERATOR

Technical Details

• Native ATC Class: ZCL_SKYLINT_PREF_COMPOSITION
• Implementation File: zcl_skylint_pref_composition.clas.abap