Enhance the Business Object Behavior With Instance Action

You will now define, implement, and expose the action deductDiscount, a non-factory instance-bound action returning itself. The action offers the possibility to deduct a certain percentage from the booking fee ( BookingFee ) of a travel instance.

The discount percentage can either be fix (30% in the present exercise) in the action implementation or be freely specified by the end-user or the calling APIs by offering an action with input parameters.

You will get familiar with both action implementations, i.e. action without and action with input parameters in the present exercise.

Hint: First, define the non-factory, instance action deductDiscount in the behavior definition of the Travel entity. This action has no input parameter.

1. Go to your behavior definition

   

   ZRAP100_R_TRAVELTP_### define the instance action without input parameter. For that, insert the following code snippet after the defined validations as shown on the screenshot below.

```ABAP
action deductDiscount result [1] $self; 
```      

 ![Travel BO Behavior Definition](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-rap100-instance-action/pp.png)      

 **Short explanation**:  
 - The name of the instance action is specified after the keyword **action**

 - The keyword **result** defines the output parameter of the action.

    - Its cardinality is specified between the square brackets (`[cardinality]`). It is a mandatory addition.  

    - **`$self`** specifies that the type of the result parameter is the same type as the entity for which the action or function is defined - i.e. the **Travel** entity type in the present exercise. The return type of the result parameter can be an entity or a structure.     

  - **Note**: The output parameter **result** can be used to store the result of an action or function in an internal table. However, it does not affect the result of an action or function that is committed to the database.   

  **Further reading**: [Action Definition](https://help.sap.com/viewer/923180ddb98240829d935862025004d6/Cloud/en-US/14ddc6b2442b4b97842af9158a1c9c44.html)

2. Save

   

   and activate

   

   the changes.

3. Now, declare the required method in behavior implementation class with the ADT Quick Fix. Set the cursor on the deductDiscount, and press Ctrl+1 to open the Quick Assist view.

   Select the entry Add method for action deductDiscount of entity zrap100_r_traveltp_### … in the view to add the required method to the local handler class.

   The result should look like this:

   

4. Save

   

   the changes.

5. Set the cursor on the method name, deductDiscount, press F3 to navigate to the declaration part of the local handler class of the behavior pool ZRAP100_BP_TRAVELTP_###.

   

6. In the declaration part set the cursor on the method name deductDiscount, press F2, and examine the full method interface.

   

   Short explanation:

   The addition FOR MODIFY after the method name, together with the addition FOR ACTION after the importing parameter, indicates that this method provides the implementation of an action. Method signature for the non-factory instance action deductDiscount:

   • IMPORTING parameter keys - a table containing the keys of the instances on which the action must be executed
   • Implicit CHANGING parameters (aka implicit response parameters):
   • result - used to store the result of the performed action.
   • mapped - table providing the consumer with ID mapping information.
   • failed - table with information for identifying the data set where an error occurred.
   • reported - table with data for instance-specific messages.

   Please note: An action is implemented in a FOR MODIFY method with the addition FOR ACTION. The signature of an action method always depends on the type of action: factory or non-factory, and instance or static. The rules for implementing an action operation in a RAP business object are explained in the respective Implementation Contract.

   Hint: Further reading: Action Implementation| Implementation Contract: Action

   Go ahead with the implementation of the action method.

Now implement the required action methods in the behavior pool of the Travel entity.

1. Implement the action method deductDiscount.

   

   The main steps of the implemented business logic:

   • Implement the custom logic to determine the new values: The discounted booking fee must be calculated for each instance.
   • The discount percentage is fix at the current stage: 30%.
   • Modify the relevant fields of the instances with the EML statement MODIFY: Here only the field BookingFee must be updated.
   • Read the data from the buffer with the EML statement READ to fill the action result parameter result.
   • The implicit response parameters are filled where necessary:
     • failed - with information for identifying the data set where an error occurred.
     • mapped - table providing the consumer with ID mapping information.
     • reported - with data for instance-specific messages in case of failure.

   Replace the current method implementation with the code snippet provided below and replace all occurrences of the placeholder ### with your group ID.

   You can use the ABAP Pretty Printer (Ctrl+F1) to format your source code.

   ABAP Copy

   **************************************************************************
   * Instance-bound non-factory action:
   * Deduct the specified discount from the booking fee (BookingFee)
   **************************************************************************
   METHOD deductDiscount.
     DATA travels_for_update TYPE TABLE FOR UPDATE ZRAP100_R_TravelTP_###.
     DATA(keys_with_valid_discount) = keys.   
   
     " read relevant travel instance data (only booking fee)
     READ ENTITIES OF ZRAP100_R_TravelTP_### IN LOCAL MODE
         ENTITY Travel
         FIELDS ( BookingFee )
         WITH CORRESPONDING #( keys_with_valid_discount )
         RESULT DATA(travels).
   
     LOOP AT travels ASSIGNING FIELD-SYMBOL(<travel>).  
         DATA(reduced_fee) = <travel>-BookingFee * ( 1 - 3 / 10 ) .  
   
         APPEND VALUE #( %tky       = <travel>-%tky
                       BookingFee = reduced_fee
                     ) TO travels_for_update.
     ENDLOOP.
   
     " update data with reduced fee
     MODIFY ENTITIES OF ZRAP100_R_TravelTP_### IN LOCAL MODE
         ENTITY Travel
         UPDATE FIELDS ( BookingFee )
         WITH travels_for_update.
   
     " read changed data for action result
     READ ENTITIES OF ZRAP100_R_TravelTP_### IN LOCAL MODE
         ENTITY Travel
         ALL FIELDS WITH
         CORRESPONDING #( travels )
         RESULT DATA(travels_with_discount).
   
     " set action result
     result = VALUE #( FOR travel IN travels_with_discount ( %tky   = travel-%tky
                                                               %param = travel ) ).
   ENDMETHOD.

   Show all 40 lines Show less

   The result should look like this:

   

   Short explanation:

   • The provided implementation is mass-enabled. This is recommended.
   • The EML statement MODIFY ENTITIES … UPDATE FIELDS is used to update specific fields of the instances.
   • The internal tables are filled inline using the constructor operator VALUE which made the need for explicit declaration obsolete.
   • The EML statement READ ENTITIES … ALL FIELDS WITH CORRESPONDING is used to read all fields of the updated instances from the buffer to fill the input paramter result.

2. Save

   

   and activate

   

   the changes.

In contrary to determinations and validations which are automatically called by the RAP runtime at the specified trigger time, actions must be explicitly exposed on the BO projection layer and called by a consumer, e.g. on the UI or directly via EML statements.

Now, you will expose the actions in the BO behavior projection and enrich the UI semantics in the CDS metadata extension to add appropriate button to the travel App.

1. Expose the actions in the BO behavior projection.

   Go to your behavior projection

   

   ZRAP100_C_TRAVELTP_### and insert the following code snippet as shown on the screenshot below. The keyword use action indicates that a behavior of the base BO is used on the projection layer.

2. Replace your code:

```ABAP  
use action deductDiscount;
```

Your source code should look like this:

![Travel BO Behavior Projection](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-rap100-instance-action/nn7.png)

2. Save

   

   and activate

   

   the changes.

   The actions are yet ready to be consumed on the UI, but they also need to be explicitly placed on the UI.

3. Enhance UI semantics of the UI service to make the action deductDiscount only visible on the object page with the label Deduct Discount. with the labels Accept Travel and Reject Travel specified.

   For that, go to your CDS metadata extension

   

   ZRAP100_C_TRAVELTP_### and replace the existing all @UI annotations placed before the element OverallStatus with the code snippet provided below as shown on the screenshot below. The semantic of the annotation @UI.identification will be enhanced for the purpose.

   Please note: Some lines in the provided code snippet are commented out using //. DO NOT remove them. You will uncomment these lines in the following exercise steps.

4. Add following annotation:

   ABAP Copy

     @UI: {
     lineItem:       [ { position: 100, importance: #HIGH }                          
                       //,{ type: #FOR_ACTION, dataAction: 'copyTravel', label: 'Copy Travel' } 
                       //,{ type: #FOR_ACTION, dataAction: 'acceptTravel', label: 'Accept Travel' }
                       //,{ type: #FOR_ACTION, dataAction: 'rejectTravel', label: 'Reject Travel' }
          ],
     identification: [ { position: 100 }                          
                      ,{ type: #FOR_ACTION, dataAction: 'deductDiscount', label: 'Deduct Discount' } 
                      //,{ type: #FOR_ACTION, dataAction: 'acceptTravel', label: 'Accept Travel' }
                      //,{ type: #FOR_ACTION, dataAction: 'rejectTravel', label: 'Reject Travel' }
          ],
       textArrangement: #TEXT_ONLY
     }

   Your source code should look like this:

   

5. Save

   

   and activate

   

   the changes.

6. Preview and test the enhanced SAP Fiori elements App.

   For example, select a travel entry, navigate to the object page, and click on the new action button Deduct Discount. Check the action result: the booking fee must have been reduced by the percentage specified in the action method.

   

   If you wish, you can also define the button on the list report page in the CDS metadata extension, activate the changes, and re-test the app.

You will enhance the action deductDiscount with an input parameter ( discount_percent ) to allow end-users or calling APIs to freely specify the percentage to be deducted from the booking fee ( BookingFee ) of a travel instance at runtime.

Action input parameters are modelled with abstract CDS entities (abstract entities). In the present example, we will use the abstract entity /dmo/a_travel_discount which defines a structure containing only one field, discount_percent, for the purpose. It is located in the package /DMO/FLIGHT_DRAFT of the flight reference scenario.

An abstract CDS entity defines the type properties of a CDS entity. Consequently, it provides metadata on element level or parameter level using CDS annotations and does not have a corresponding implementation nor an underlying persistency.

1. Let’s have a look at the abstract entity defined in the data definition /DMO/A_Travel_Discount. You can use the shortcut Ctrl+Shift+A to open the data definition.

   

   Short explanation:

   • An abstract entity is defined by the statement define abstract entity followed by the CDS entity name.
   • The current abstract entity defines a structure with only one field or element; The element name ( discount_percent ) and the element type ( /DMO/BT_DiscountPercentage ) are specified.
   • It is not here the case, but if required, it is possible to…
     • specify a label using the element annotation @EndUserText.label.
     • specify a value help using the element annotation @Consumption.valueHelpDefinition.
     • hide an element using the element annotation @UI.hidden.

2. Go to the behavior definition ZRAP100_R_TRAVELTP_### and add the addition parameter /dmo/a_travel_discount to the action definition.

   The source code should now look as follows:

   ABAP Copy

   action deductDiscount parameter /dmo/a_travel_discount result [1] $self;

   The abstract entity /dmo/a_travel_discount is used after the keyword parameter to specify the parameter structure. The present action will only have one parameter ( discount_percent ) as defined in the abstract entity.

3. Save

   

   and activate

   

   the changes.

You will now adjust the implementation of the business logic for the instance non-factory action deductDiscount with the input parameter deduct_discount in the behavior pool ZRAP100_BP_TRAVELTP_###.

Only entered values greater than 0 and lower than 100 will be allowed.

Depending on the type of action, the importing parameter keys has different components. The parameter structure %param for parameter input is imported by action with parameters. The parameter structure is used to access the passed values of the input parameters: deduct_discount in the present scenario - i.e. %param-deduct_discount.

1. Go to your behavior pool ZRAP100_BP_TRAVELTP_### and adjust the action method deductDiscount.

   The required adjustments of the current business logic:

   For all passed Travel instances: Read and check the validity of the specified discount values from the parameter structure %param, and remove invalid ones: 0 < %param-deduct_discount <= 100
   Implement the custom logic to determine the new values: The discounted booking must be calculated for each instance according to the respective %param-deduct_discount value - instead of the fix discount (30%).

   Replace the current method implementation with the code snippet provided below. Do not forget to replace all occurrences of the placeholder ### with your group ID.

   You can use the ABAP Pretty Printer (Ctrl+F1) to format your source code.

   ABAP Copy

   **************************************************************************
   * Instance-bound non-factory action with parameter `deductDiscount`:
   * Deduct the specified discount from the booking fee (BookingFee)
   **************************************************************************
   METHOD deductDiscount.
     DATA travels_for_update TYPE TABLE FOR UPDATE ZRAP100_R_TravelTP_###.
     DATA(keys_with_valid_discount) = keys.
   
     " check and handle invalid discount values
     LOOP AT keys_with_valid_discount ASSIGNING FIELD-SYMBOL(<key_with_valid_discount>)
       WHERE %param-discount_percent IS INITIAL OR %param-discount_percent > 100 OR %param-discount_percent <= 0.
   
       " report invalid discount value appropriately
       APPEND VALUE #( %tky                       = <key_with_valid_discount>-%tky ) TO failed-travel.
   
       APPEND VALUE #( %tky                       = <key_with_valid_discount>-%tky
                       %msg                       = NEW /dmo/cm_flight_messages(
                                                         textid = /dmo/cm_flight_messages=>discount_invalid
                                                         severity = if_abap_behv_message=>severity-error )
                       %element-TotalPrice        = if_abap_behv=>mk-on     
                       %op-%action-deductDiscount = if_abap_behv=>mk-on
                     ) TO reported-travel.
   
       " remove invalid discount value
       DELETE keys_with_valid_discount.
     ENDLOOP.
   
     " check and go ahead with valid discount values
     CHECK keys_with_valid_discount IS NOT INITIAL.
   
     " read relevant travel instance data (only booking fee)
     READ ENTITIES OF ZRAP100_R_TravelTP_### IN LOCAL MODE
       ENTITY Travel
         FIELDS ( BookingFee )
         WITH CORRESPONDING #( keys_with_valid_discount )
       RESULT DATA(travels).
   
     LOOP AT travels ASSIGNING FIELD-SYMBOL(<travel>).
       DATA percentage TYPE decfloat16.
       DATA(discount_percent) = keys_with_valid_discount[ key draft %tky = <travel>-%tky ]-%param-discount_percent.
       percentage =  discount_percent / 100 .
       DATA(reduced_fee) = <travel>-BookingFee * ( 1 - percentage ) .
   
       APPEND VALUE #( %tky       = <travel>-%tky
                       BookingFee = reduced_fee
                     ) TO travels_for_update.
     ENDLOOP.
   
     " update data with reduced fee
     MODIFY ENTITIES OF ZRAP100_R_TravelTP_### IN LOCAL MODE
       ENTITY Travel
         UPDATE FIELDS ( BookingFee )
         WITH travels_for_update.
   
     " read changed data for action result
     READ ENTITIES OF ZRAP100_R_TravelTP_### IN LOCAL MODE
       ENTITY Travel
         ALL FIELDS WITH
         CORRESPONDING #( travels )
       RESULT DATA(travels_with_discount).
   
     " set action result
     result = VALUE #( FOR travel IN travels_with_discount ( %tky   = travel-%tky
                                                             %param = travel ) ).
   ENDMETHOD.

   Show all 65 lines Show less

   The result should look like this:

   

2. Save

   

   and activate

   

   the changes.

You can now test the new behavior of the action button Deduct Discount on the enhanced travel app.

1. Preview and test the enhanced Fiori elements travel app. Go to the object page of a given entry, click on the new action button Deduct Discount. A dialog will now be prompted for you to enter a valid discount value, i.e. > 0 and <= 100, and confirm.

   Check the result.

   

   You can also repeat the test with an invalid value.