How to Create RAP Business Events in an On-Premise system

To produce and raise an event you need first to define your RAP Business Object which produce the event. For this, you will create a booking application. The event will be sent whenever a booking flight is cancelled.

1. Open ADT and open your system.

2. If you do not have an ABAP Package create a new one. Please be sure if your package name is started with Z like

- Name: `ZEVENT_BOOKING_####`
- Description: `define a RAP event`

![new](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/1-1.png)

3. Right-click on your package and create a new database table

- Name: `ZBOOKING_####`
- Description: `DB for booking`

![database](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/1-2.png)

![database](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/1-3.png)

4. Replace the default code with the code snippet provided below and replace all placeholder #### with your group ID using the Replace All function Ctrl+F.

```ZBOOKING_####
@EndUserText.label : 'DB for booking'
@AbapCatalog.enhancement.category : #NOT_EXTENSIBLE
@AbapCatalog.tableCategory : #TRANSPARENT
@AbapCatalog.deliveryClass : #A
@AbapCatalog.dataMaintenance : #RESTRICTED
define table zbooking_#### {
key client            : abap.clnt not null;
key travel_id         : /dmo/travel_id not null;
agency_id             : /dmo/agency_id;
customer_id           : /dmo/customer_id;
begin_date            : /dmo/begin_date;
end_date              : /dmo/end_date;
@Semantics.amount.currencyCode : 'zbooking_####.currency_code'
booking_fee           : /dmo/booking_fee;
@Semantics.amount.currencyCode : 'zbooking_####.currency_code'
total_price           : /dmo/total_price;
currency_code         : /dmo/currency_code;
description           : /dmo/description;
overall_status        : /dmo/overall_status;
attachment            : /dmo/attachment;
mime_type             : /dmo/mime_type;
file_name             : /dmo/filename;
created_by            : abp_creation_user;
created_at            : abp_creation_tstmpl;
last_changed_by       : abp_locinst_lastchange_user;
last_changed_at       : abp_locinst_lastchange_tstmpl;
local_last_changed_at : abp_lastchange_tstmpl;
}  

```

5. Save and activate your table.

![database](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/1-4.png)

1. Right-click your package and select New > ABAP Class from the context menu.

   

2. Maintain the required information and click Next

   • Name: ZCL_BOOKING_GEN_DATA_####
   • Description: Generate demo data

   

3. Select a transport request and click Finish to create the class.

4. Copy the code below to your CDS data model and replace #### with your number

    ```ZCL_BOOKING_GEN_DATA_####
   
    CLASS zcl_booking_gen_data_#### DEFINITION
    PUBLIC
    FINAL
    CREATE PUBLIC .
   
    PUBLIC SECTION.
   
        INTERFACES if_oo_adt_classrun.
    PROTECTED SECTION.
    PRIVATE SECTION.
    ENDCLASS.
   
    CLASS zcl_booking_gen_data_#### IMPLEMENTATION.
   
    METHOD if_oo_adt_classrun~main.
        DATA:
        group_id   TYPE string VALUE '####',
        attachment TYPE /dmo/attachment,
        file_name  TYPE /dmo/filename,
        mime_type  TYPE /dmo/mime_type.
   
    *   clear data
        DELETE FROM zbooking_####.
   
        "insert travel demo data
        INSERT zbooking_0000  FROM (
            SELECT
            FROM /dmo/travel AS travel
            FIELDS
                travel~travel_id        AS travel_id,
                travel~agency_id        AS agency_id,
                travel~customer_id      AS customer_id,
                travel~begin_date       AS begin_date,
                travel~end_date         AS end_date,
                travel~booking_fee      AS booking_fee,
                travel~total_price      AS total_price,
                travel~currency_code    AS currency_code,
                travel~description      AS description,
                CASE travel~status    "[N(New) | P(Planned) | B(Booked) | X(Cancelled)]
                WHEN 'N' THEN 'O'
                WHEN 'P' THEN 'O'
                WHEN 'B' THEN 'A'
                ELSE 'X'
                END                     AS overall_status,
                @attachment             AS attachment,
                @mime_type              AS mime_type,
                @file_name              AS file_name,
                travel~createdby        AS created_by,
                travel~createdat        AS created_at,
                travel~lastchangedby    AS last_changed_by,
                travel~lastchangedat    AS last_changed_at,
                travel~lastchangedat    AS local_last_changed_at
                ORDER BY travel_id UP TO 10 ROWS
        ).
        COMMIT WORK.
        out->write( |Demo data generated for table zbooking_{ group_id }. | ).
    ENDMETHOD.
    ENDCLASS.
   
    ```
   

5. Save and activate your data model.

6. Run your console application. For that, select your ABAP class zcl_booking_gen_data_####, select the run button > Run As > ABAP Application (Console) F9 or press F9. A message will be displayed.

   

   

7. Open your database table ZBOOKING_#### and press F8 to start the data preview and display the filled database entries, i.e. travel data.

   

Create your OData v4 based UI services with the built-in ADT generator. The generated business service will be transactional, draft-enabled, and enriched with UI semantics for the generation of the Fiori elements app.

1. Right-click your database table ZBOOKING_#### and select Generate ABAP Repository Objects from the context menu.

   

2. Maintain the required information and click Next:

   • Description: Booking App ###
   • Generator: ABAP RESTful Application Programming Model: UI Service

   

3. Maintain the required information on the Configure Generator dialog to provide the name of your data model and generate them.

   RAP Layer	Artefacts	Artefact Name
   Business Object
   	Data Model	Data Definition Name: ZEVENT_R_BOOKINGTP_####
   		Alias Name: BOOKING
   	Behavior	Implementation Class: ZEVENT_BP_BOOKINGTP_####
   		Draft Table Name: ZEVENT_BOOK0000
   Service Projection (BO Projection)		Name: ZEVENT_C_BOOKINGTP_0000
   Business Services
   	Service Definition	Name: ZEVENT_UI_BOOKING_0000
   	Service Binding	Name: ZEVENT_UI_BOOKING_04_0000
   		Binding Type: OData V4 - UI

   

4. Verify the maintained entries and press Next to confirm. The needed artefacts will be generated.

   

5. Select a transport request and click Finish to confirm the dialog.

   

6. Go to the Project Explorer, select your package, refresh it by pressing F5, and check all generated ABAP repository objects.

   

1. Open your service binding ZEVENT_UI_BOOKING_04_#### and click Publish.

   

2. Double-click on the entity BOOKING in the Entity Set and Association section to open the Fiori elements App Preview.

   

3. Click the GO Button to load the data and check your result.

   

   

1. You need to create an event which is raised when a booking flight is cancelled. For this, open ZEVENT_BP_BOOKINGTP_#### and add a new event to the business object. The event name is BookingCancelled.

   Code Copy

     event BookingCancelled parameter ZEVENT_D_BOOKING_CANCEL_####;

   Your behavior definition will be looking like this:

   

2. In addition,provide a cancellation reason and description. This can be done via a parameter define as a data definition (abstract entity) called ZEVENT_D_BOOKING_CANCEL_####.

   

3. Copy the code below in this definition. Do not forget to save and activate.

```ZEVENT_D_BOOKING_CANCEL_####
 @EndUserText.label: 'booking cancelation reason'
 define abstract entity ZEVENT_D_BOOKING_CANCEL_####
 {
    REasonCode : abap.char(2);  
    Description : abap.char(64);
 }

```

![parameter](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/5-3.png)

Now create the event binding for your newly created business event. This event binding is needed to map an event to a RAP entity event.

1. Right-click on your package and create an event binding

- Name: `ZEVENT_CANCEL_FLIGHT_####`
- Description: `cancel flight event`

![binding](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/6-1.png)

![binding](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/6-2.png)

3. Here fill all fields out, to get errors gone. You can freely choose these names to specify your event with some considerations explained below

- Namespace: `zevent####` (No camel case and no space)
- Business Object: `booking` (No Space)
- Business Object Operation: `Delete`

![error](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/6-5.png)

4. Click Add to add items.

- Root Entity Name: `ZEVENT_R_BOOKINGTP_####` (your behavior definition)
- Entity Event Name: `BOOKINGCANCELLED` (Event name in your behavior definition)


![item](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/6-7.png)

![item](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/6-3.png)

5. Save and activate your event binding.

6. As you can see at the screenshot, Type (aka topic) is a concatenation of the three attributes (name space, business object, business object operation) and ends with the version of the event. The wildcard * points to the corresponding event e.g. created. This is relevant for addressing the events to the Event Mesh. Copy this address for later use zevent####.booking.Delete.v*.

![type](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-environment-create-s4hana-rap-business-events/6-4.png)

1. Open your behavior definition ZEVENT_R_BOOKINGTP_#### and add with additional save like following:

   

2. Now open the implementation class ZEVENT_BP_BOOKINGTP_#### and navigate to Local Type.

   

3. Add the lcl_event_handler class and save modified method in there:

   Code Copy

       CLASS lcl_event_handler DEFINITION INHERITING FROM cl_abap_behavior_saver.
   
       PROTECTED SECTION.
           METHODS save_modified REDEFINITION.
   
       ENDCLASS.
   
       CLASS lcl_event_handler IMPLEMENTATION.
   
       METHOD save_modified.
           IF delete-booking IS NOT INITIAL.
          RAISE ENTITY EVENT zevent_r_bookingtp_####~BookingCancelled
        FROM VALUE #( FOR <s_travel> IN delete-booking  ( TravelID = <s_travel>-TravelID  %param = VALUE #( reasoncode ='02'  description = 'cancelled by customer' ) ) ).
           ENDIF.
       ENDMETHOD.
       ENDCLASS.

   

4. Save and activate your class.

After an event is raised, it must be delivered to the SAP Event Mesh to be consumed later. The connection between the system and the SAP Event Mesh is achieved through a so-called channel. In an on premise system you can directly create the channel in the system.

A channel represents a single connection to a service instance of the SAP Event Mesh. As a prerequisite, you need to prepare an SAP Event Mesh instance in your SAP business technology platform system and download the service key of this instance.

1. Open SAP Logon and login in your on premise system and run the transaction /n/IWXBE/CONFIG

   

2. Press via Service Key to create a new channel.

   

3. Enter a channel name and description and copy the service key of your SAP Event Mesh instance into the corresponding field and click Save.

   

4. Your newly created channel will now show up in the channel list. Activate the channel by pressing the Activate button. If the channel is active, it should appear with a green box under active channels.

   

   

After creating a channel, you can decide which events should be listed on this channel. This explicit step of maintaining an outbound binding is necessary to publish events by an SAP S/4HANA system.

1. Run /n/IWXBE/OUTBOUND_CFG and select your channel.

   

2. Click Create new topic binding icon and choose the topic which is generated during the event binding creation, zevent####.booking.Delete.v*.

   

   

   

3. Check your topic is listed.

   

In the SAP Event Mesh system, create a queue for the selected instance and subscribe it to your topic. For more information on how to create a queue, check [ this ] (https://blogs.sap.com/2022/08/19/an-introduction-to-enterprise-event-enablement-for-sap-btp-abap-environment/) blog post.

The structure of the topic should be like: your event mesh instance namespace/ce/the event type you are generated and are subscribed to: zevent####/booking/delete/*.

The Topic will look like: PmEvnt/PmEvnt.sap/Demo/ce/zevent####/booking/Delete/*

After you created a queue for the selected instance in the SAP Event Mesh system and subscribe it to your topic,

1. Back to ADT and open service binding ZEVENT_UI_BOOKING_04_####, choose BOOKING and click Preview.

   

2. Click Go to load all bookings. Select an entry with the chosen ID and delete it. An event will be raised then.

   

   

3. Back to your queue, here you can see that a message is in your queue.

   

4. Click Test and choose your queue. Click Consume message.

   

5. Check the Message Data

   

6. To monitor the generated event on SAP Logon, open SAP Logon and run the transaction /n/IWXBE/EVENT_MONITOR. Choose your channel and click Execute