This document is part 5 of what builds on my other example: "Part 4: basic HCM Process and Forms scenario (Include a DropDown List for Country Selection)" which can be accessed at: http://scn.sap.com/docs/DOC-35588
Backend Services are important components of HCM Processes and Forms. Let’s create one to validate that the form user only selects country code “USA”. This example uses the configuration and form development we was completed in the prior example: "Part 4".
Note: You normally want to call a Backend Service when a user presses the “Check and Send” button on your form. This is a common scenario to validate what was entered. However, there are instances when you want to call a Backend Service to be called when the form is loading. For example, you might have a position ID being sent to the form. For this position, you wish to also display the position holder name and employee number, you can also use a BE service for that too. However, there is a slight difference. When you want to call a Backend Service on form load, you use the Initialize Method of the Backend Service. For a normal “Check and Send” Scenario, you use the Do Operations method of the Backend Service.
Follow this path:
Go into this node and you will see something similar to the following:
Select "New Entries" at the top and put in your Backend Service Key and Backend Service Name, like:
I used “ZGS_COUNTRY_VALIDATION” for the Backend Service Key Name. Save your entries. At this point you have defined a generic service. Now we need to “implement” code for the service.
Follow this path:
When you execute this node, you will get a pop-up window showing all existing "generic services".
Click the "Create Implementation" icon and you will be prompted with the following:
Select the green check and complete the implementation properties information like the following:
You will then be prompted to supply the properties information for the Badi Implementation and Implementing Class:
Use the following naming format:
• BAdI Implementation: ZHRASR_(service key without prefix for ZGS or ZAS)
• Implementation class: ZCL_HRASR_(service key without prefix for ZGS or ZAS)
So for our service key of “ZGS_COUNTRY_VALIDATION ", the entries would be:
ZHRASR_COUNTRY_VALIDATION
ZCL_HRASR_COUNTRY_VALIDATION
Results:
Continue and Save your implementation – you will see the following screen:
Now we need to give this implementation a unique Service ID by which HCM Process & Forms can call it.
Double Click on the “Filter Val.” as shown in the screen shot below:
Click the "Create Filter Combination" button. Your screen now looks like:
Double-click the "????" under "Value 1" and complete the filter for your service ID:
Select Continue and save and activate your work.
You have now created a definition and implementation for your backend service. You have not put any logic into theservice. That comes next. Click on the “Technical Details” tab and find the class name for your implementation:
The class name in this example is: ZCL_HRASR_COUNTRY_VALIDATION and you can edit the class in transaction SE24 directly.
The first item to take care of is defining attributes of the class. Every BE Service should have an attribute which stores the name of the BE Service. There should also be an attribute which stores the name of the operation being performed. There could be more than one operation defined in a single backend service. Lastly, for each form field being passed to the BE Service both the field name and field data type need to be defined in the attributes. Define the following attributes:
C_GENERIC_SERVICE_NAME Type: ASR_FORM_SCENARIO_SERVICE Value: 'ZGS_COUNTRY_VALIDATION'
C_OPER_CHECK_STATE Type: ASR_BACKEND_OPERATION Value: 'CHECK_COUNTRY'
C_FLD_COUNTRY Type: FIELDNAME Value: 'LAND1'
C_DTEL_ COUNTRY Type: ASR_FIELD_DATA_ELEMENT_NAME Value: 'LAND1'
Results:
So basically, you have defined the unique name of you BE service in your attributes. You have also defined one operation: “CHECK_COUNTRY”. Remember, you can have more than one operation. Also, you defined the field name and field data type. These are definitions of all the fields that you expect to pass between the form and the BE Service.
Now you can go to the methods tab and start implementing them. There are some method definitions already defined:
*Note: if you ever want to see how SAP defines some of their own BE Services, you can do a search in SE24 for “CL_HRASR00_GS*”.
First: create a new method in your class as follows:
Name: GET_FIELDS_OF_OPERATION
Level: Instance Method
Visibility: Private
Description: Determine Fields/Parameters of Operation
Define the following parameters for this method:
OPERATION Importing Type ASR_BACKEND_OPERATION
FIELDNAMES Returning Type HRBAS_FIELDLIST_TAB
Add the following code to the method:
clear fieldnames.
case operation.
when c_oper_check_state.
append c_fld_country to fieldnames.
when others.
assert 1 = 0. "called for an operation that is not supported
endcase.
Now create a new method as follows:
Name: EXTRACT_RELEVANT_DATASETS
Level: Instance Method
Visibility: Private
Description: Extract Data Records Relevant for Field Group
Define the following parameters for this method:
FIELDGROUP Importing Type ASR_FIELD_GROUP
OPERATION Importing Type ASR_BACKEND_OPERATION
SERVICE_DATASETS Importing Type HRASR00GENSRV_DATASET_TAB
HELP_DATASETS Importing Type HRASR00GS_HELP_DATASET_TAB
RELEVANT_SERVICE_DATASETS Exporting Type HRASR00GENSRV_DATASET_TAB
RELEVANT_HELP_DATASETS Exporting Type HRASR00GS_HELP_DATASET_TAB
Add the following code to this method:
data relevant_help_dataset_wa type hrasr00gs_help_dataset.
data current_index type i.
clear relevant_service_datasets.
clear relevant_help_datasets.
data operation_fieldnames type hrbas_fieldlist_tab.
operation_fieldnames = get_fields_of_operation( operation ).
relevant_service_datasets = service_datasets.
delete relevant_service_datasets where fieldgroup <> fieldgroup.
relevant_help_datasets = help_datasets.
loop at relevant_help_datasets into relevant_help_dataset_wa.
current_index = sy-tabix.
read table operation_fieldnames transporting no fields
with key table_line = relevant_help_dataset_wa-fieldname.
if sy-subrc <> 0. "field is not relevant
delete relevant_help_datasets index current_index.
endif.
endloop.
Now create a new method as follows:
Name: RESTORE_RELEVANT_DATASETS
Level: Instance Method
Visibility: Private
Description: Return Data Records Relevant for Field Group
Define the following parameters for this method:
FIELDGROUP Importing Type ASR_FIELD_GROUP
OPERATION Importing Type ASR_BACKEND_OPERATION
RELEVANT_SERVICE_DATASETS Importing Type HRASR00GENSRV_DATASET_TAB
RELEVANT_HELP_DATASETS Importing Type HRASR00GS_HELP_DATASET_TAB
SERVICE_DATASETS Changing Type HRASR00GENSRV_DATASET_TAB
HELP_DATASETS Changing Type HRASR00GS_HELP_DATASET_TAB
Add the following code to this method:
data relevant_service_dataset_wa type hrasr00gensrv_dataset.
data service_dataset_wa type hrasr00gensrv_dataset.
data relevant_help_dataset_wa type hrasr00gs_help_dataset.
field-symbols <service_dataset_wa> type hrasr00gensrv_dataset.
field-symbols <relevant_service_dataset_wa> type hrasr00gensrv_dataset.
field-symbols <help_dataset_wa> type hrasr00gs_help_dataset.
data operation_fieldnames type hrbas_fieldlist_tab.
operation_fieldnames = get_fields_of_operation( operation ).
loop at relevant_service_datasets assigning <relevant_service_dataset_wa> where fieldgroup = fieldgroup.
read table service_datasets into service_dataset_wa
with key fieldgroup = <relevant_service_dataset_wa>-fieldgroup
fieldname = <relevant_service_dataset_wa>-fieldname
fieldindex = <relevant_service_dataset_wa>-fieldindex.
if sy-subrc = 0.
service_dataset_wa = <relevant_service_dataset_wa>.
modify service_datasets index sy-tabix from service_dataset_wa.
else.
service_dataset_wa = <relevant_service_dataset_wa>.
append service_dataset_wa to service_datasets.
endif.
endloop.
loop at service_datasets into service_dataset_wa where fieldgroup = fieldgroup and fieldindex > 1.
read table relevant_service_datasets into relevant_service_dataset_wa
with key fieldgroup = service_dataset_wa-fieldgroup
fieldname = service_dataset_wa-fieldname
fieldindex = service_dataset_wa-fieldindex.
if sy-subrc <> 0.
delete service_datasets.
endif.
endloop.
loop at help_datasets assigning <help_dataset_wa>.
read table operation_fieldnames transporting no fields
with key table_line = <help_dataset_wa>-fieldname.
if sy-subrc <> 0.
continue.
endif.
read table relevant_help_datasets into relevant_help_dataset_wa
with key fieldname = <help_dataset_wa>-fieldname
fieldindex = <help_dataset_wa>-fieldindex.
if sy-subrc = 0.
<help_dataset_wa> = relevant_help_dataset_wa.
endif.
endloop.
Now insert the following code into method GET_FIELD_INFO:
data field_info type hrasr00gs_field_info.
data service_field type fieldname.
clear field_infos.
loop at service_fields into service_field.
case service_field.
when c_fld_country.
clear field_info.
field_info-fieldname = c_fld_country.
field_info-field_data_element_name = c_dtel_country.
field_info-supports_value_help = space.
field_info-supports_default_value = space.
append field_info to field_infos.
endcase.
endloop.
Now insert the following code into method GET_OPERATIONS:
data operation type hrasr00gs_operation.
clear operations.
clear operation.
operation-operation = c_oper_check_state.
operation-fieldnames = get_fields_of_operation( operation-operation ).
append operation to operations.
Now create a new method as follows:
Name: DO_OPERA_CHECK_COUNTRY
Level: Instance Method
Visibility: Private
Description: Check Valid Country
Define the following parameters for this method:
SPECIAL_FIELDS Importing Type HRASR00VALUE_OF_FIELD_TAB
NO_AUTH_CHECK Importing Type BOOLE_D
MESSAGE_HANDLER Importing Type Ref To IF_HRBAS_MESSAGE_HANDLER
HELP_DATASETS Changing Type HRASR00GS_HELP_DATASET_TAB
SERVICE_DATASETS Changing Type HRASR00GENSRV_DATASET_TAB
Add the following code to the method:
data message type symsg.
data message_dummy type string.
field-symbols <service_dataset_fs> type hrasr00gensrv_dataset.
data: address_country type land1.
read table service_datasets assigning <service_dataset_fs>
with key fieldname = c_fld_country.
if sy-subrc = 0.
address_country = <service_dataset_fs>-fieldvalue.
endif.
if ( address_country ne 'US' ).
message-msgty = 'E'.
message-msgno = '009'.
message-msgv1 = 'Please Enter a US Address'.
message_handler->add_message( exporting message = message ).
exit.
endif.
Now insert the following code into method DO_OPERATIONS:
data service_operation_wa type hrasr00genserv_operation.
data help_dataset type hrasr00gs_help_dataset.
data relevant_help_datasets type hrasr00gs_help_dataset_tab.
data relevant_service_datasets type hrasr00gensrv_dataset_tab.
data message_dummy type string.
data message type symsg.
loop at service_operations into service_operation_wa.
call method me->extract_relevant_datasets
exporting
fieldgroup = service_operation_wa-fieldgroup
operation = service_operation_wa-operation
service_datasets = service_datasets
help_datasets = help_datasets
importing
relevant_service_datasets = relevant_service_datasets
relevant_help_datasets = relevant_help_datasets.
case service_operation_wa-operation.
when c_oper_check_state.
call method me->do_opera_check_country
exporting
special_fields = special_fields
no_auth_check = no_auth_check
message_handler = message_handler
changing
help_datasets = relevant_help_datasets
service_datasets = relevant_service_datasets.
when others.
message e102(hrasr00_genserv) with service_operation_wa-operation c_generic_service_name
into message_dummy.
move-corresponding sy to message.
message_handler->add_message( exporting message = message ).
return.
endcase.
call method me->restore_relevant_datasets
exporting
fieldgroup = service_operation_wa-fieldgroup
operation = service_operation_wa-operation
relevant_service_datasets = relevant_service_datasets
relevant_help_datasets = relevant_help_datasets
changing
service_datasets = service_datasets
help_datasets = help_datasets.
endloop.
Now your method for the Backend Service is complete. Yes, there is a lot of code added to methods in your class. The good news is that once you have done this once, any other Backend Services you create, will model the same code. So, you might want to create a template that you can always use. The only thing left is to map the Backend Service to the fields in your process configuration.
Call Up Transaction: HRASR_DT and select your process from the drop down. Under Form Scenarios, double click Back-End Services:
Insert an entry for your newly created Backend Service:
Expand “Field Groups and Operations”:
Create the Field Group: FG1 and Choose Your Operation: CHECK_COUNTRY
Expand “Fields”:
Define the following field:
Now is a good time to test. You can either logon to the portal and select your process or launch directly using:
http://yourserver.com/sap/bc/webdynpro/sap/asr_process_execute?sap-client=<yourclient #>&sap-language=EN
Result (choosing country other than US):
As you can see, the logic in the Backend Service was executed and threw an error when a country other than "US" was selected..
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