Return a list of all atributes of a persistent class in abap

Question

I got a persistent class on a custom table. Now with GET_PERSISTENT_BY_QUERY I can get a list of objects. How can I now get those Objects with all of their atributes printed to the user (e.g as ALV)?

Can I call an instance function if i click on it somehow?

Answer 1

Based on the answer of gert beukema I have written a helper class (with major improvements like accepting more than public simple atributes without failing).

class ZCL_PS_OBJECT_TO_STRUCTURE_HLP definition
  public
  create private .

public section.

  class-methods REFTAB_TO_STRUCTURE_LIST
    importing
      !IT_REFRENCE_TABLE type OSREFTAB
    returning
      value(RR_OBJECT_ATTRIBUTES_TABLE) type ref to DATA .
  class-methods CREATE_FIELDCAT
    importing
      !IR_OBJ_DESC type ref to CL_ABAP_CLASSDESCR
    returning
      value(RO_FIELD_CAT) type LVC_T_FCAT .
protected section.
private section.
ENDCLASS.



CLASS ZCL_PS_OBJECT_TO_STRUCTURE_HLP IMPLEMENTATION.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_PS_OBJECT_TO_STRUCTURE_HLP=>CREATE_FIELDCAT
* +-------------------------------------------------------------------------------------------------+
* | [--->] IR_OBJ_DESC                    TYPE REF TO CL_ABAP_CLASSDESCR
* | [<-()] RO_FIELD_CAT                   TYPE        LVC_T_FCAT
* +--------------------------------------------------------------------------------------</SIGNATURE>
  METHOD CREATE_FIELDCAT.

    LOOP AT IR_obj_desc->attributes ASSIGNING FIELD-SYMBOL(<fs_attr_desc>).
      APPEND INITIAL LINE TO ro_field_cat ASSIGNING FIELD-SYMBOL(<fs_field_cat>).
      <fs_field_cat>-fieldname = <fs_attr_desc>-name.
      <fs_field_cat>-intlen    = <fs_attr_desc>-length.
      <fs_field_cat>-datatype  = <fs_attr_desc>-type_kind.
      <fs_field_cat>-outputlen  = calculate a good outputlength (double when hex)
    ENDLOOP.


  ENDMETHOD.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_PS_OBJECT_TO_STRUCTURE_HLP=>REFTAB_TO_STRUCTURE_LIST
* +-------------------------------------------------------------------------------------------------+
* | [--->] IT_REFRENCE_TABLE              TYPE        OSREFTAB
* | [<-()] RR_OBJECT_ATTRIBUTES_TABLE     TYPE REF TO DATA
* +--------------------------------------------------------------------------------------</SIGNATURE>
  METHOD reftab_to_structure_list.

    DATA: lr_obj_desc   TYPE REF TO cl_abap_classdescr,
          lr_query_data TYPE REF TO data,
          lt_fieldcat  TYPE lvc_t_fcat.

    FIELD-SYMBOLS: <fs_table> TYPE STANDARD TABLE.

    LOOP AT it_refrence_table ASSIGNING FIELD-SYMBOL(<fs_object>).

      AT FIRST.
        lr_obj_desc ?= cl_abap_typedescr=>describe_by_object_ref( p_object_ref = <fs_object> ).

        lt_fieldcat = create_fieldcat( ir_obj_desc = lr_obj_desc ).

        CALL METHOD cl_alv_table_create=>create_dynamic_table
          EXPORTING
*           i_style_table             =
            it_fieldcatalog           = lt_fieldcat
*           i_length_in_byte          =
          IMPORTING
            ep_table                  = rr_object_attributes_table
*            ep_table                  = lr_query_data
*           e_style_fname             =
          EXCEPTIONS
            generate_subpool_dir_full = 1
            OTHERS                    = 2.
*        IF sy-subrc <> 0.
*          do some errorhandling here
*        ENDIF.

        ASSIGN rr_object_attributes_table->* TO <fs_table>.
*        ASSIGN lr_query_data->* TO <fs_table>.

      ENDAT. "first

      APPEND INITIAL LINE TO <fs_table> ASSIGNING FIELD-SYMBOL(<fs_line>).

      LOOP AT lr_obj_desc->attributes ASSIGNING FIELD-SYMBOL(<fs_attr_desc>).
        ASSIGN COMPONENT <fs_attr_desc>-name OF STRUCTURE <fs_line> TO FIELD-SYMBOL(<fs_attr_value>).
        DATA(getter) = 'GET_' && <fs_attr_desc>-name.
        TRY .
            CALL METHOD <fs_object>->(getter) RECEIVING result = <fs_attr_value>.
          CATCH cx_sy_dyn_call_illegal_method. "get_method is protected or private
            CLEAR <fs_attr_value>.
          CATCH cx_sy_dyn_call_illegal_type.
            "what to do with a list?
        ENDTRY.

      ENDLOOP.

    ENDLOOP.

  ENDMETHOD.
ENDCLASS.

Now with that helperclass I do not have to recode it always I want a list out of a Object.

In a programm the call is e.G like this:

DATA: lt_query_data  TYPE osreftab,
      lt_query_table TYPE REF TO data.

FIELD-SYMBOLS <fs_table>.


lt_query_data = zca_ps_user=>agent->if_os_ca_persistency~get_persistent_by_query(
  i_query = cl_os_system=>get_query_manager( )->create_query( )
  ).

  CALL METHOD zcl_ps_object_to_structure_hlp=>reftab_to_structure_list
    EXPORTING
      it_refrence_table          = lt_query_data
    RECEIVING
      rr_object_attributes_table = lt_query_table.

  IF lt_query_table IS INITIAL.
    LEAVE.
  ENDIF.

  ASSIGN lt_query_table->* TO <fs_table>.

*Create a ALV

  DATA: lr_alv TYPE REF TO cl_salv_table .

  cl_salv_table=>factory( IMPORTING r_salv_table = lr_alv
    CHANGING t_table = <fs_table> )
      .

  lr_alv->display( ).

Ps: I wanted to edit the answer, but it was not accepted.