ABAP Keyword Documentation → ABAP Programming Guidelines → Structure and Style → Source Code Organization
Multiple Use of Include Programs
Other versions: 7.31 | 7.40 | 7.54
Background
From a technical point of view, it is possible to use an include program multiple times by integrating it more than once into a master program or different master programs.
Rule
Do not use include programs more than once
Use an include program for the modularization of exactly one master program. It must not be integrated into multiple different master programs. Also, an include program should only be integrated once within a master program.
Details
The multiple use of include programs is highly problematic conceptually. This particularly concerns the use of include programs for the reuse of:
- Type definitions
- Data declarations
- Local classes
- Procedure implementations
We strongly recommended using only suitable means for reuse, such as global classes or interfaces, for the reasons specified in the following sections.
Restricted maintainability
Increased resource consumption
The memory consumption also increases if an include program is used multiple times within one master program (for example, through integration into the source code of multiple function modules of a function group or into the source code of multiple methods of a class) because this expands the master program unnecessarily. When using centrally defined, standalone types and storing required constants in suitable classes or interfaces, there remains no conceivable scenario where it would be useful to use include programs multiple times within a master program.
Missing semantic context
Bad Example
The following source code shows an include program that contains declarations of constants intended for use in multiple programs. According to the above rule, procedures of this type are no longer permitted.
*& Include Z_ORDERS_OF_MAGNITUDE
*&---------------------------------------------*
CONSTANTS:
mega TYPE p DECIMALS 6 VALUE '1000000.0',
kilo TYPE p DECIMALS 6 VALUE '1000.0',
milli TYPE p DECIMALS 6 VALUE '0.001',
micro TYPE p DECIMALS 6 VALUE '0.000001'.
Good Example
The following source code shows the same declarations of constants as in the above example, but this time in a global class suitable for reuse. Here, a corresponding ABAP Unit test method would even be possible that checks the consistency of the constants.
PUBLIC SECTION.
CONSTANTS:
mega TYPE p DECIMALS 6 VALUE '1000000.0',
kilo TYPE p DECIMALS 6 VALUE '1000.0',
milli TYPE p DECIMALS 6 VALUE '0.001',
micro TYPE p DECIMALS 6 VALUE '0.000001'.
ENDCLASS.