Program to the capability; let the object do its job

An interface reference can point to different objects that implement the same contract. The caller sends the same method call; ABAP dispatches it to the implementation belonging to the actual object. This is polymorphism.

Same call, variable implementation

DATA(notifier) TYPE REF TO lif_notifier.
notifier = NEW lcl_log_notifier( ).
DATA(result) = notifier->send( iv_message = 'Parcel ready' ).

The variable is typed to lif_notifier, not to lcl_log_notifier. Later, a different implementation can be assigned without changing the consumer, as long as it fulfills that interface.

What this buys you

• The workflow is not filled with IF channel = ... branches.
• Each implementation owns its delivery detail.
• Tests can provide a fake notifier and check the consumer’s behavior.

Polymorphism does not require an interface in every case; an eligible superclass reference can also refer to subclass objects. Interface-based polymorphism is often a clean fit for roles/capabilities.

Practice

Declare an interface reference, assign an implementing class instance, call send, and set result. Add WRITE result. in a classic report or the Cloud class-run output call. This exercise checks patterns and does not execute them.

Version note: Dynamic method dispatch is an ABAP Objects concept; the concrete APIs and language-version restrictions remain environment-dependent.

Sources

• SAP Samples, ABAP Object Orientation: polymorphism and interfaces
• SAP Help Portal, ABAP Objects overview

DATA(notifier) TYPE REF TO lif_notifier.
notifier = NEW lcl_log_notifier( ).
DATA(result) = notifier->send( iv_message = 'Parcel ready' ).

WRITE result.

out->write( result ).