Friday, March 27, 2015

User Hooks in Oracle HRMS

User Hooks in Oracle HRMS

API User Hooks refers to points in the API execution to which customers can
attach or extend business logic. User-defined code can be “hooked” into these
predefined locations, and executed in conjunction with the API call.

User code can: extend validation on Oracle HRMS tables, maintain data in
external customer-specific tables (not part of Oracle Applications)
simultaneously with the Oracle HRMS updates through the API, or send alerts at
particular Oracle HRMS events.

The explicit limitation for customer extensions remains—any and all HRMS
data manipulation must be performed by HRMS APIs.

User Hooks offer similar functionality to the Custom Library, but at the database
rather than in the Forms front end.

User Hooks allow logic extensions without changing delivered API code. Hooks
are regenerated at upgrade. However, since schema changes may occur at any
time, all custom procedures should be tested after upgrade. Additionally, API
Hooks are available to any interface that calls the API, such as: Forms, Self-
Service, and Data Pump.

Not all HRMS Forms use APIs; a trace can identify whether a Form uses APIs.
Only Forms that call APIs will execute a User Hooked code. If the Form does
not use APIs, the same code extension can be implemented in Custom Library.
The HR_API_HOOKS table holds all available API hooks for APIs in
HR_API_MODULES table.

Implementing User Hooks

Four steps are required to implement API User Hooks:

1. Determine the API to which you need to hook extra logic

2. Write the PL/SQL procedure that executes your logic.

3. Register your procedure with one or more specific user hooks.

4. Run the pre-processor program that hooks your PL/SQL procedure to the
hook(s). 

Oracle HRMS has several types of hooks. Only Business Process Hooks
correspond to Business Process APIs. They are used when logic must extend
beyond the standard business process. Only Business Process Hooks are
Supported for Customer use. A list can be obtained by running the following
query:

select module_name
from hr_api_modules
where api_module_type='BP';

The $PER_TOP/admin/sql/hrahkpar.sql script provides listing of each API, its
hooks, and corresponding procedure parameters.Sample Hook Implementation
Get Hook Information
SELECT      ahk.api_hook_id,
ahk.api_module_id,
ahk.hook_package,
                    ahk.hook_procedure
  FROM       hr_api_hooks ahk, hr_api_modules ahm
 WHERE      ahm.module_name = 'CREATE_PERSON_ABSENCE'   -- Module Name
                    AND ahm.api_module_type = 'BP'
AND ahk.api_hook_type = 'AP'
                    AND ahk.api_module_id = ahm.api_module_id


Hook Registration
DECLARE
l_api_hook_call_id      NUMBER;
l_object_version_number NUMBER;
l_sequence              NUMBER;
BEGIN
SELECT HR_API_HOOKS_S.NEXTVAL
  INTO   l_sequence
 FROM   dual;
 Hr_Api_Hook_Call_Api.create_api_hook_call
 (p_validate                 => FALSE,
  p_effective_date           => TO_DATE('01-JAN-1952','DD-MON-YYYY'),
  p_api_hook_id              =>
  p_api_hook_call_type       => 'PP',
  p_sequence                 => l_sequence,
  p_enabled_flag             => 'Y',
  p_call_package             => 'LMHR_HOOK_VALIDATIONS_PKG',    -- Custom Package
 p_call_procedure           => UPPER('Validate_Objectives_Weight'),  -- Custom procedure
 p_api_hook_call_id         => l_api_hook_call_id,
 p_object_version_number    => l_object_version_number);

  DBMS_OUTPUT.PUT_LINE('l_api_hook_call_id '|| l_api_hook_call_id);
END ;

Run the pre-processor script
        Run pre-processor script hrahkone.sql with module name as parameter (PER_TOP/admin/sql/hrahkone.sql).It compile API hook. After running this your APIhook Package should have custom procedure call.

Delete custom code from APIuser Hook

      Get Hook Call ID and Object Version_number
Select  api_hook_call_id,object_version_number from HR_API_HOOK_CALLS where call_package like ‘LMHR%’ and call_procedure = UPPER('Validate_Objectives_Weight')

Hook Deletion
BEGIN
 Hr_Api_Hook_Call_Api.delete_api_hook_call  (     p_validate         => FALSE,
                                                                                p_api_hook_call_id => ,
                                                                               p_object_version_number =>2
                                                                           );
  DBMS_OUTPUT.PUT_LINE('deleted Successfully');
END;


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