ABAP Objects supports nested or compound interfaces. A compound interface contains one or more interfaces as component interfaces. These component interfaces may contain further interfaces as components. Several levels of nesting are possible.
All of the component interfaces must already exist in the class library.
If you select the Only modeled option, the system does not create a corresponding entry in the class pool.
The system adds the entry in the class library.
All of the component interfaces that you entered belong to the same nesting level. When a class uses a compound interface, it must implement all methods of all component interfaces.
All the interfaces involved are implemented at the same level irrespective of their nesting hierarchy. You can access their components using their original names in the form:
<Interface name>~<component>
You can assign all the components of the interfaces alias names serving as abbreviations for their full names. To do so, choose Aliases and enter the alias name. In addition to the name, you can also define the visibility (PUBLIC, PROTECTED, PRIVATE) and thus restrict the use of alias names.