Modify variants of a report program using ABAP

class ZCL_CONSTANT definition
  public
  final
  create public .

public section.

  class-data MS_RECORD type TVARVC .    " Constant record of the last search
  class-data MT_RECORD type TVARVC_T .  " Constant records of the last search
  class-data MV_VALUE type TVARV_VAL .  " Constant value of the last search
  class-data MT_BUFFER type TVARVC_T .  " Constant records found in the previous searches
  constants MC_SIGN_INCLUDE type DDSIGN value 'I'. "#EC NOTEXT
  constants MC_OPTION_EQUAL type DDOPTION value 'EQ'. "#EC NOTEXT
  constants MC_OPTION_CONTAIN type DDOPTION value 'CP'. "#EC NOTEXT

  class-methods CLEAR .
  type-pools ABAP .
  class-methods GET
    importing
      !IV_NAME type RVARI_VNAM
      !IB_USE_BUFFER type ABAP_BOOL default ABAP_TRUE
    exporting
      !EV_VALUE type ANY
      !ES_RECORD type TVARVC
      !ET_RECORD type TVARVC_T
      !ER_RANGE type STANDARD TABLE
    exceptions
      ER_RANGE_TYPE_NOT_VALID .
  class-methods GET_VALUE
    importing
      !IV_NAME type RVARI_VNAM
      !IB_USE_BUFFER type ABAP_BOOL default ABAP_TRUE
    returning
      value(RV_VALUE) type TVARV_VAL .
  class-methods GET_SEVERAL
    importing
      !IV_NAME_PATTERN type RVARI_VNAM
      !IB_USE_BUFFER type ABAP_BOOL default ABAP_TRUE
    returning
      value(RT_RECORD) type TVARVC_T .
  class-methods SEARCH
    importing
      !IV_NAME type RVARI_VNAM optional
      !IV_NAME_PATTERN type RVARI_VNAM optional
      !IR_RANGE_NAME type EFG_TAB_RANGES optional
      !IB_USE_BUFFER type ABAP_BOOL default ABAP_TRUE
    returning
      value(RB_FOUND) type ABAP_BOOL .
  PROTECTED SECTION.
private section.
ENDCLASS.

CLASS ZCL_CONSTANT IMPLEMENTATION.

* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_CONSTANT=>CLEAR
* +-------------------------------------------------------------------------------------------------+
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method CLEAR.

*******************************************************************************
* Clear the previous search results
*******************************************************************************

    CLEAR: mt_buffer, ms_record, mt_record, mv_value.

  endmethod.

* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_CONSTANT=>GET
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_NAME                        TYPE        RVARI_VNAM
* | [--->] IB_USE_BUFFER                  TYPE        ABAP_BOOL (default =ABAP_TRUE)
* | [<---] EV_VALUE                       TYPE        ANY
* | [<---] ES_RECORD                      TYPE        TVARVC
* | [<---] ET_RECORD                      TYPE        TVARVC_T
* | [<---] ER_RANGE                       TYPE        STANDARD TABLE
* | [EXC!] ER_RANGE_TYPE_NOT_VALID
* +--------------------------------------------------------------------------------------</SIGNATURE>
  METHOD get.

*******************************************************************************
* Get records of a single Constant
*******************************************************************************

    DATA:
         lb_found_in_buffer            TYPE abap_bool      VALUE abap_false,
         ls_range                      TYPE REF TO data.

    FIELD-SYMBOLS:
         <lv_range_field>              TYPE any,
         <ls_range>                    TYPE any,
         <ls_record>                   TYPE tvarvc.

* 1. If the buffer use is requested, look for the Constant records in the buffer
    CLEAR: es_record, et_record, ev_value, er_range,
           ms_record, mt_record, mv_value.

    IF ib_use_buffer = abap_true.
      LOOP AT mt_buffer ASSIGNING <ls_record> WHERE name = iv_name.
        APPEND <ls_record> TO mt_record.
      ENDLOOP.

      IF mt_record IS NOT INITIAL.
        lb_found_in_buffer = abap_true.
        READ TABLE mt_record INTO ms_record INDEX 1.
        mv_value = ms_record-low.
      ENDIF.
    ENDIF.

* 2. If the Constant records have not been found in the buffer, look for the Constant records in the DB table TVARVC
    IF lb_found_in_buffer = abap_false.
      search( iv_name       = iv_name
              ib_use_buffer = ib_use_buffer ).
    ENDIF.

* 3. Set the requested exporting parameters
    " Structure of TVARVC
    IF es_record IS REQUESTED.
      es_record = ms_record.
    ENDIF.

    " Table of TVARVC
    IF et_record IS REQUESTED.
      et_record = mt_record.
    ENDIF.

    " Value of TVARVC-LOW
    IF ev_value IS REQUESTED.
      ev_value = mv_value.
    ENDIF.

    " Range table generated based on the found TVARVC records
    IF er_range IS REQUESTED.
      TRY.
          LOOP AT mt_record ASSIGNING <ls_record>.
            UNASSIGN <ls_range>.
            CREATE DATA ls_range LIKE LINE OF er_range.
            ASSIGN ls_range->* TO <ls_range>.
            IF <ls_range> IS ASSIGNED.
              UNASSIGN <lv_range_field>.
              ASSIGN COMPONENT 'SIGN' OF STRUCTURE <ls_range> TO <lv_range_field>.
              IF <lv_range_field> IS ASSIGNED.
                <lv_range_field> = <ls_record>-sign.
              ENDIF.
              UNASSIGN <lv_range_field>.
              ASSIGN COMPONENT 'OPTION' OF STRUCTURE <ls_range> TO <lv_range_field>.
              IF <lv_range_field> IS ASSIGNED.
                <lv_range_field> = <ls_record>-opti.
              ENDIF.
              UNASSIGN <lv_range_field>.
              ASSIGN COMPONENT 'LOW' OF STRUCTURE <ls_range> TO <lv_range_field>.
              IF <lv_range_field> IS ASSIGNED.
                <lv_range_field> = <ls_record>-low.
              ENDIF.
              UNASSIGN <lv_range_field>.
              ASSIGN COMPONENT 'HIGH' OF STRUCTURE <ls_range> TO <lv_range_field>.
              IF <lv_range_field> IS ASSIGNED.
                <lv_range_field> = <ls_record>-high.
              ENDIF.
              APPEND <ls_range> TO er_range.
            ENDIF.
          ENDLOOP.
        CATCH cx_root.
          " Raise an exception if the range table could not be generated
          RAISE er_range_type_not_valid. " The range type of ER_RANGE is not adapted to the found value
      ENDTRY.

    ENDIF.

  ENDMETHOD.

* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_CONSTANT=>GET_SEVERAL
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_NAME_PATTERN                TYPE        RVARI_VNAM
* | [--->] IB_USE_BUFFER                  TYPE        ABAP_BOOL (default =ABAP_TRUE)
* | [<-()] RT_RECORD                      TYPE        TVARVC_T
* +--------------------------------------------------------------------------------------</SIGNATURE>
  METHOD get_several.

*******************************************************************************
* Get records of several Constants
*******************************************************************************

* Look for the requested Constants in the DB table TVARVC
    search( iv_name_pattern = iv_name_pattern
            ib_use_buffer   = ib_use_buffer   ).

* Set the exporting parameter if requested
    IF rt_record IS REQUESTED.
      APPEND LINES OF mt_record TO rt_record.
    ENDIF.

  ENDMETHOD.

* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_CONSTANT=>GET_VALUE
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_NAME                        TYPE        RVARI_VNAM
* | [--->] IB_USE_BUFFER                  TYPE        ABAP_BOOL (default =ABAP_TRUE)
* | [<-()] RV_VALUE                       TYPE        TVARV_VAL
* +--------------------------------------------------------------------------------------</SIGNATURE>
  METHOD get_value.

*******************************************************************************
* Get value of a single Constant
*******************************************************************************

* Look for a single Constant value from the DB table TVARVC
    get( iv_name       = iv_name
         ib_use_buffer = ib_use_buffer ).

* Set the exporting parameter if requested
    IF rv_value IS REQUESTED.
      rv_value = mv_value.
    ENDIF.

  ENDMETHOD.

* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_CONSTANT=>SEARCH
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_NAME                        TYPE        RVARI_VNAM(optional)
* | [--->] IV_NAME_PATTERN                TYPE        RVARI_VNAM(optional)
* | [--->] IR_RANGE_NAME                  TYPE        EFG_TAB_RANGES(optional)
* | [--->] IB_USE_BUFFER                  TYPE        ABAP_BOOL (default =ABAP_TRUE)
* | [<-()] RB_FOUND                       TYPE        ABAP_BOOL
* +--------------------------------------------------------------------------------------</SIGNATURE>
  METHOD search.

*******************************************************************************
* Search Constants in the DB table TVARVC
* (also useful for buffer pre-load to avoid several accesses to the database)
*******************************************************************************

    DATA:
         lr_name             TYPE RANGE OF rvari_vnam,
         ls_name             LIKE LINE OF lr_name,
         ls_range_name       LIKE LINE OF ir_range_name.

* Look for the requested Constant records
    CLEAR: ms_record, mt_record, mv_value.

    " Prepare the search criteria
    IF iv_name IS NOT INITIAL.
      ls_name-sign = mc_sign_include.
      ls_name-option = mc_option_equal.
      ls_name-low = iv_name.
      APPEND ls_name TO lr_name.
    ENDIF.
    IF iv_name_pattern IS NOT INITIAL.
      ls_name-sign = mc_sign_include.
      ls_name-option = mc_option_contain.
      ls_name-low = iv_name_pattern.
      APPEND ls_name TO lr_name.
    ENDIF.
    IF ir_range_name IS NOT INITIAL.
      LOOP AT ir_range_name INTO ls_range_name.
        MOVE-CORRESPONDING ls_range_name TO ls_name.
        APPEND ls_name TO lr_name.
      ENDLOOP.
    ENDIF.

    " Look for the Constants in the DB table TVARVC
    IF lr_name IS NOT INITIAL.
      SELECT * FROM tvarvc
               INTO TABLE mt_record
               WHERE name IN lr_name.

      IF sy-subrc = 0.
        " Set the found results in the static class attributes
        READ TABLE mt_record INTO ms_record INDEX 1.
        mv_value = ms_record-low.

        " Add the found Constants to the buffer
        IF ib_use_buffer = abap_true.
          APPEND LINES OF mt_record TO mt_buffer.
          SORT mt_buffer.
          DELETE ADJACENT DUPLICATES FROM mt_buffer.
        ENDIF.
      ENDIF.
    ENDIF.

    IF rb_found IS REQUESTED.
      IF mt_record IS NOT INITIAL.
        rb_found = abap_true.
      ELSE.
        rb_found = abap_false.
      ENDIF.
    ENDIF.

  ENDMETHOD.
ENDCLASS.