By default, the generation classes for long text inherit from /SCT/QP_CL_GEN_STD_TEXT.

The type definition for the parameter transfer is standardized:

The CHANGING parameter should be called CS_TEXT_STRUC and be of type /SCT/QP_S_ITHEAD.

The method name is free, but in contrast to the generation of values, only one generation method is allowed for object type TEXT, and it must be entered in Customizing. 

The possible languages for which the generation is to determine a long text should also be maintained in Customizing.

See: /SCT/ZQP_CL_GEN_TEXT