Types of Package Interfaces for Structure Packages (SAP Library

Types of Package Interfaces for Structure Packages

Structure package interfaces define the use relationships at the highest level of the package hierarchy. For example, in order to use the repository objects from the structure package BASIS within the structure package APPL, APPL needs to declare a use access to the filter package interface _BASIS_FILTER. This package interface allows repository objects from BASIS to be used externally.

In general, there are three types of package interfaces available in structure packages:

Virtual Standard Package Interface

The package interface (implicitly) contains the repository objects of all non-encapsulated packages belonging to the structure package.

Filter Package Interface

A filter (filter package interface) is a special package interface that can only be defined at the structure package level. It is necessary to add such a filter in the following use cases:

● A client (consumer) package hierarchy wants to use the virtual standard package interface of a server (provider) package hierarchy.

● A client package hierarchy wants to use the package interfaces at the first non-structure package level.

The declaration of the use access to the filter package interface takes place at the top-level client package only. With this use access, a contract between the provider and the client package hierarchy is established. In other words: it is the prerequisite that both, the virtual standard package interfaces and the package interfaces of the first non-structure level become visible for the client package hierarchy.

However, a use access declaration in a regular development package on the client-side is not necessary.

Standard Package Interface

This type of package interfaces contains a set of repository objects from the provider package hierarchy that are chosen for external usage. A structure package can have multiple standard package interfaces. These package interfaces do not require a declaration of use access to the filter package interface on the client-side.