Create a Global ABAP Class

Now you will create the an object with the type of a new global class, for retrieving backend data.

1. In the run method, create an instance of class zcl_invoice_retrieval using the new operator:

data(invoices) = new ZCL_INVOICE_RETRIEVAL( ).

1. Since this class does not yet exist, you will get a syntax error. To create the class, place the cursor on the class name and open the Quick Assist by choosing Ctrl+1. In the Quick Assist menu, double-click on Create global class zcl_invoice_retrieval:

   

2. A wizard will appear to create a new ABAP class. Enter:

   • a name ZCL_INVOICE_RETRIEVAL
   • a description invoice Retrieval

3. Choose Finish:

   

A new editor will be opened showing the class you have created, ZCL_INVOICE_RETRIEVAL.

Since release 7.40, ABAP permits inline declarations. For more information, see:
- Old and new ABAP syntax – overview sheet
- 7.4 Release News - Inline Declaration I

To read the records from the database, you need to call a method get_items_from_db.
This method does not yet exist so we will create it with a Quick Assist as follows:

1. Still in your program, enter an instance method call:

   data(invoice_items) = invoices->get_items_from_db( ).
   
   

2. Since the method does not exist, you will get an error. Position the cursor on the name of the missing method and choose Quick Assist, i.e. Ctrl+1. In the Quick Assist menu, choose Create method get_items_from_db

   

3. In the Create class wizard that appears, create a public method without parameters, simply by choosing Finish:

   

In the class ZCL_INVOICE_RETRIEVAL, the Quick Assist creates:

• a method definition
• an empty method implementation :

In a previous tutorial (Display database content and run SQL queries), you generated a SELECT statement using the SQL console. The advantage of using the SQL console is that you can reduce errors by defining clauses - like JOIN, WHERE, or ORDER BY - simply by using the Data Preview. The SQL Console automatically generates the correct SELECT statement for you.

You will now use this generated SELECT statement in your class to retrieve the data from the database.

Note: We strongly recommend that you gain an understanding of the SQL Console by working through this previous tutorial. However, if you no longer have the SQL console open, you can simply copy the following SELECT statement into the method implementation (see step 3. below).

1. Go back to the SQL console:

   

2. Resize the query section and copy the Open SQL statement using the shortcut Ctrl+C:

   

3. Now, in your class ZCL_INVOICE_RETRIEVAL, paste the statement into the method implementation of get_items_from_db (using Ctrl+V):

The code from the SQL console should look like this. Note that the SQL Console query section automatically adds the INTO clause INTO TABLE @DATA(LT_RESULT).

SELECT
   SNWD_BPA~COMPANY_NAME,
   SNWD_SO_INV_ITEM~GROSS_AMOUNT,
   SNWD_SO_INV_ITEM~CURRENCY_CODE,
   SNWD_SO_INV_HEAD~PAYMENT_STATUS
 FROM
  SNWD_SO_INV_ITEM JOIN SNWD_SO_INV_HEAD ON SNWD_SO_INV_ITEM~PARENT_KEY = SNWD_SO_INV_HEAD~NODE_KEY JOIN SNWD_BPA ON SNWD_SO_INV_HEAD~BUYER_GUID = SNWD_BPA~NODE_KEY
 WHERE
  SNWD_SO_INV_ITEM~CURRENCY_CODE = 'USD'
 ORDER BY  SNWD_BPA~COMPANY_NAME
 INTO TABLE @DATA(LT_RESULT).
 UP TO 100 ROWS.

The statement UP TO 100 ROWS will cause an error. Delete it.

In a previous tutorial (Create a structure), you created an ABAP Data Dictionary structure. Now, you will use this structure.

First, we will declare an internal table, lt_result explicitly. Then we will define the type of the returning parameter for your method get_items_from_db.

1. First position the cursor on the inline declared variable lt_result and open Quick Fix by choosing Ctrl+1:

   

2. Select Declare local variable lt_result explicitly by double clicking in the Quick Fix menu:

   

This creates an internal table referring to a local type and automatically generates the following code:

TYPES: BEGIN OF helper_type,
         company_name TYPE snwd_bpa-company_name,
         gross_amount TYPE snwd_so_inv_item-gross_amount,
         currency_code TYPE snwd_so_inv_item-currency_code,
         payment_status TYPE snwd_so_inv_head-payment_status,
       END OF helper_type.
DATA: lt_result TYPE STANDARD TABLE OF helper_type.`

It also replaces INTO TABLE @DATA(lt_result) with INTO TABLE @lt_result.
The @ character is simply an escape character to comply with the new Open SQL syntax. For more information, see:
- 7.4 Release News - Inline Declaration I

In the method call that you have generated:

1. Remove the commented exporting parameters list_display, r_container, and container_name using the shortcut Ctrl+D
2. Uncomment the importing parameter r_salv_table using the shortcut Ctrl+7 and manually assign an inline variable alv_table to it
3. Assign the variable invoice_items to the changing parameter t_table
4. Then call the display method of ALV_TABLE : alv_table->display( ) :

Your method should look like this:

cl_salv_table=>factory(

         IMPORTING
           r_salv_table   =     data(alv_table)

          CHANGING
            t_table        = invoice_items ).

       alv_table->display(  ).

Your program code should now look like this:

*&---------------------------------------------------------------------*
*& Report zjp_invoice_items_euro
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT zjp_invoice_items_euro.



class lcl_main definition create private.

  public section.
    CLASS-METHODS create
      RETURNING
        value(r_result) TYPE REF TO lcl_main.

    methods run.

  protected section.
  private section.

endclass.

class lcl_main implementation.
  method create.
    create object r_result.
  endmethod.

  method run.
    data(invoices) = new ZCL_INVOICE_RETRIEVAL( ).
    data(invoice_items) = invoices->get_items_from_db( ).

       cl_salv_table=>factory(
         IMPORTING
           r_salv_table   =     data(alv_table)
          CHANGING
            t_table        = invoice_items ).

       alv_table->display(  ).

 endmethod.
endclass.

start-of-selection.
lcl_main=>create( )->run( ).

Your class code should now look like this:

CLASS zcl_invoice_retrieval DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC .

  PUBLIC SECTION.
    TYPES: ty_table_of_zso_invoice_item TYPE STANDARD TABLE OF zso_invoice_item WITH DEFAULT KEY.
    METHODS get_items_from_db
    RETURNING
    VALUE(lt_result) type ty_table_of_zso_invoice_item.
  PROTECTED SECTION.
  PRIVATE SECTION.
ENDCLASS.

CLASS zcl_invoice_retrieval IMPLEMENTATION.

  METHOD get_items_from_db.

  SELECT
    snwd_bpa~company_name,
    snwd_so_inv_item~gross_amount,
    snwd_so_inv_item~currency_code,
    snwd_so_inv_head~payment_status

  FROM
   snwd_so_inv_item
   JOIN snwd_so_inv_head ON snwd_so_inv_item~parent_key = snwd_so_inv_head~node_key
   JOIN snwd_bpa ON snwd_so_inv_head~buyer_guid = snwd_bpa~node_key

   INTO TABLE @lt_result

  WHERE
   snwd_so_inv_item~currency_code = 'USD'

  ORDER BY
   snwd_bpa~company_name.

    ENDMETHOD.
ENDCLASS.