Use sub-classes to enable callers to distinguish error situations

CLASS cx_bad_generation_variable DEFINITION INHERITING FROM cx_generation_error.
CLASS cx_bad_code_composer_template DEFINITION INHERITING FROM cx_generation_error.

METHODS generate RAISING cx_generation_error.

TRY.
    generator->generate( ).
  CATCH cx_bad_generation_variable.
    log_failure( ).
  CATCH cx_bad_code_composer_template INTO DATA(bad_template_exception).
    show_error_to_user( bad_template_exception ).
  CATCH cx_generation_error INTO DATA(other_exception).
    RAISE EXCEPTION NEW cx_application_error( previous =  other_exception ).
ENDTRY.

CLASS cx_generation_error DEFINITION ...
  PUBLIC SECTION.
    TYPES error_code_type TYPE i.
    CONSTANTS:
      BEGIN OF error_code_enum,
        bad_generation_variable    TYPE error_code_type VALUE 1,
        bad_code_composer_template TYPE error_code_type VALUE 2,
        ...
      END OF error_code_enum.
    DATA error_code TYPE error_code_type.

TRY.
    generator->generate( ).
  CATCH cx_generation_error INTO DATA(exception).
    CASE exception->error_code.
      WHEN cx_generation_error=>error_code_enum-bad_generation_variable.
      WHEN cx_generation_error=>error_code_enum-bad_code_composer_variable.
      ...
    ENDCASE.
ENDTRY.