method _diff
  by kernel module abversdiff_Diff.
endmethod.

The method _diff in the class cl_abap_diff_internal is implemented using a kernel module abversdiff_Diff. Here’s an explanation of what this signifies:

Understanding the _diff Method:

This is evident in contexts where its invocation returns a table indicating the diffs, which can then be utilized for further processing or analysis in the ABAP program logic.

Kernel Module:

By implementing the method with a kernel module, the method _diff delegates its functionality to a lower-level module that is part of the ABAP runtime kernel. This often results in performance enhancements, since kernel modules are optimized for speed and efficiency.

Purpose:

The _diff method is designed to compute the differences (or “diffs”) between two input tables, likely enabling versioning or synchronization features. This is common in systems requiring constant reconciliation of different data states or changes.

Implementation:

Since the actual logic is handled by the kernel module abversdiff_Diff, you will not see the method’s detailed implementation within the class. Instead, the SAP system relies on its internal, pre-built function.

Integration:

It is typically used in a scenario where there’s a need to compare source and target data structures, where the primary focus might be on performance due to potentially large data sets.

Usage:

CLASS zcl_table_diff_example DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC .

  PUBLIC SECTION.
    TYPES: BEGIN OF ty_diff_line,
             line_number TYPE i,
             operation TYPE c LENGTH 10,
             line_content TYPE string,
           END OF ty_diff_line.
    TYPES tt_diff_result TYPE STANDARD TABLE OF ty_diff_line WITH EMPTY KEY.

    " Method to perform the diff
    METHODS diff_tables
      IMPORTING
        it_target TYPE STANDARD TABLE
        it_source TYPE STANDARD TABLE
      EXPORTING
        et_diff TYPE tt_diff_result
      RAISING
        cx_no_memory
        cx_sy_open_sql .

  PRIVATE SECTION.
    " Private method to simulate diff operation
    METHODS _diff_simulation
      IMPORTING
        it_target TYPE STANDARD TABLE
        it_source TYPE STANDARD TABLE
      EXPORTING
        et_diff TYPE tt_diff_result.

ENDCLASS.

CLASS zcl_table_diff_example IMPLEMENTATION.

  METHOD diff_tables.
    " Simulate a call to perform diff using a private method
    _diff_simulation(
      EXPORTING
        it_target = it_target
        it_source = it_source
      IMPORTING
        et_diff = et_diff
    ).
  ENDMETHOD.

  METHOD _diff_simulation.
    " This is a dummy implementation and should be replaced with actual diff calculation logic
    LOOP AT it_target INTO DATA(target_line).
      READ TABLE it_source WITH KEY table_line = target_line TRANSPORTING NO FIELDS.
      IF sy-subrc <> 0.
        " Line exists in target but not in source
        APPEND VALUE #( line_number = sy-tabix
                        operation = 'DELETE'
                        line_content = target_line ) TO et_diff.
      ENDIF.
    ENDLOOP.

    LOOP AT it_source INTO DATA(source_line).
      READ TABLE it_target WITH KEY table_line = source_line TRANSPORTING NO FIELDS.
      IF sy-subrc <> 0.
        " Line exists in source but not in target
        APPEND VALUE #( line_number = sy-tabix
                        operation = 'INSERT'
                        line_content = source_line ) TO et_diff.
      ENDIF.
    ENDLOOP.
  ENDMETHOD.

ENDCLASS.