User Hook Registration

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saudapk
Posts: 13
Joined: Tue Feb 28, 2012 3:51 pm
Location: Qatar

User Hook Registration

Post by saudapk »

Hi All,
I have an issue with my User hook registration. I created the package , procedure and all and also registered the user hook with p_validate parameter = False and run the preprocessor also. The user Hook is type BP and to the Person Extra info table (HR_PERSON_EXTRA_INFO_BK1 pkg ). Its all working fine and firing whenever needed.
But the same user hook I wanted to change the P_validate Parameter to TRUE. I tried by updating the existing userhook using hr_api_hook_call_api.update_api_hook_call and also tried by deleting the existing user hook and re creating with parameter as TRUE. But the user hook is not got registered when that parameter is set to TRUE. But i can delete and recreate it using that paramater False and working fine.
Actually I want to register it with the p_Validate paramete as TRUE.
If anybody any idea please share.

Thanks
numan.alselmi
Posts: 3
Joined: Fri May 18, 2012 5:26 am
Location: Saudi Arabia

Post by numan.alselmi »

try this
----------------------------


PURPOSE
-------

To explain how to add extra logic to the Business APIs using User Hooks.

SCOPE & APPLICATION
-------------------

This document explains the advantages and disadvantages of User Hooks, and how
to implement them.


CONTENTS
---------

1. General Introduction
2. Advantages
3. Disadvantages
4. Implementing User Hooks
5. Available User Hooks
5.1. Business Process Hooks
5.2. Row Handler Hooks
5.3. Available Data Values
6. Using User Hooks
6.1. Writing Custom PL/SQL procedure
6.2. Registering User Hook
6.3. Running the Preprocessor
6.4. Running the Custom Procedure

1. General Introduction
-----------------------

API User Hooks allow users to extend the business logic of the standard
business rules that are executed by APIs. This is done by allowing custom
procedures to be called at specific points in the standard APIs. For instance,
a user may want to implement User Hooks for one of the following reasons:

. To extend the validation of data beyond what the standard system
provides.

. To maintain data held in extra customer specific tables (not part
of Oracle Applications) as it is entered.

. To send alerts when particular events happen within Oracle Human
Resources Management System(HRMS.)

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

The table HR_API_HOOKS contains all the hooks available for each API module
listed in the HR_API_MODULES table.

2. Advantages
-------------

User Hooks allow extra business logic to be inserted in exactly the right
place in the application without needing to bespoke any of the standard
APIs. Upgrades are no problem as the hooks will be regenerated during the
upgrade process. However, Oracle reserves the right to change the HR schema at
any time, which may necessitate modifications to customized PL/SQL procedures.

The main advantages of hooks over custom library are that they only need to be
implemented in one place whereas custom libary modifications could conceivably
have to be made on several clients. They are also immediately available to
any interface that calls the API. For example, Forms, Self Service, Data Pump,
etc.

3. Disadvantages
----------------

A customized procedure called by a User Hook will only work if the API that the
call has been added to is executed. It sounds obvious. However, at the time of
writing there are still a large number of forms that don't call APIs. The Enter
Person Information form is one of them. Therefore, any hook added to the
Create_Employee API will not be executed from this form. It is policy to
eventually convert all existing forms to call APIs but this will not be a short
term process. Unfortunately,there is no list available which indicates which
forms call APIs and which do not. The only certainty is that all new forms will
call APIs. A sensible approach to any implementation of configuration logic,
therefore, if required to be executed by a standard form, is for the user to
use a hook if the form calls a supported API, and custom library if not.

4. Implementing User Hooks
--------------------------

There are basically 4 steps to implementing API User Hooks.

1. Choose the API you wish to hook some extra logic to.

2. Write the PL/SQL procedure that you wish to be called by the hook.

3. Register or associate the procedure you have written with one or
more specific user hooks.

4. Run the pre-processor program which builds the logic to execute your
PL/SQL procedure from the hook specified in 3.

Step 1 will be dealt with in more detail in Section 5 , and 2 to 4. in
Section 6.

5. Available User Hooks
-----------------------

Hooks are not available to alternative interface APIs,such as
CREATE_GB_EMPLOYEE. Any extra logic should be associated with the main API. In
this case, CREATE_EMPLOYEE. A list of alternative APIs,current at the time of
writing follows:

select module_name from hr_api_modules
where api_module_type = 'AI'

MODULE_NAME
------------------------------
CREATE_GB_APPLICANT
CREATE_GB_EMPLOYEE
CREATE_GB_PERSONAL_PAY_METHOD
CREATE_GB_PERSON_ADDRESS
CREATE_GB_SECONDARY_EMP_ASG
CREATE_US_APPLICANT
CREATE_US_EMPLOYEE
CREATE_US_PERSONAL_PAY_METHOD
CREATE_US_PERSON_ADDRESS
CREATE_US_SECONDARY_EMP_ASG
UPDATE_GB_EMP_ASG
UPDATE_GB_PERSON
UPDATE_GB_PERSONAL_PAY_METHOD
UPDATE_GB_PERSON_ADDRESS
UPDATE_US_EMP_ASG
UPDATE_US_PERSON
UPDATE_US_PERSONAL_PAY_METHOD
UPDATE_US_PERSON_ADDRESS

User Hooks are also not provided for utility type APIs such as
CREATE_MESSAGE_LINE.

A list of each API,it's hooks, and the parameters available to a procedure
called by that hook, can be obtained by running the script
$PER_TOP/admin/sql/hrahkpar.sql.

There are 5 different types of User Hook. Two for Business Process APIs
(Before Process and After Process), and 3 more for Row Handler APIs (After
Insert,After Update and After Delete).

5.1 Business Process Hooks
--------------------------

The Business Process hooks should be used if extra logic is required on top of
the standard business process logic. For instance, CREATE_EMPLOYEE,
UPDATE_ELEMENT_ENTRY,etc. A full list can be obtained by running the following
script:

select module_name from hr_api_modules
where api_module_type='BP'

The two types of Business Process hook available are:

Before Process - These hooks execute logic before the main API logic. The
majority of validation will not have taken place. No database
changes will have been made.

After Process - These hooks will execute after the main API validation has
completed and database changes made. If the main validation
failed then the user hook will not be called.

The following sql retrieves the hook details of the After Process
hook for the CREATE_EMPLOYEE business process.

SQL> select ahk.api_hook_id,
2 ahk.hook_package,
3 ahk.hook_procedure
4 from hr_api_hooks ahk,
5 hr_api_modules ahm
6 where ahm.module_name='CREATE_EMPLOYEE'
7 and ahm.api_module_type = 'BP'
8 and ahk.api_hook_type = 'AP'
9 and ahk.api_module_id=ahm.api_module_id
10
SQL> /

API_HOOK_ID HOOK_PACKAGE HOOK_PROCEDURE
----------- ------------------------------ ------------------------------
63 HR_EMPLOYEE_BK1 CREATE_EMPLOYEE_A


5.2 Row Handler Hooks
---------------------

The Row Handler hooks should be used if extra logic is required prior to
performing an Insert,Update or Delete on a specific table. As all the main APIs
call the row handlers, these hooks would be executed by any API that updates
the specific table. A full list of the Row Handler APIs can be obtained by
running the following sql:

select module_name from hr_api_modules
where api_module_type='RH'

The 3 types of Row Handler hook available are:

After Insert
After Update
After Delete

The following sql retrieves hook details for the After Insert hook for
the PER_ALL_PEOPLE_F table.

1 select ahk.api_hook_id,
2 ahk.hook_package,
3 ahk.hook_procedure
4 from hr_api_hooks ahk,
5 hr_api_modules ahm
6 where (ahm.module_name='PER_ALL_PEOPLE_F'
7 or ahm.module_name='PER_PEOPLE_F')
8 and ahm.api_module_type = 'RH'
9 and ahk.api_hook_type = 'AI'
10* and ahk.api_module_id=ahm.api_module_id
SQL> /

API_HOOK_ID HOOK_PACKAGE HOOK_PROCEDURE
----------- ------------------------------ ------------------------------
66 PER_PER_RKI AFTER_INSERT

*** Note:
The module_name should be PER_ALL_PEOPLE_F, but on early versions of R11
PER_PEOPLE_F was erroneously used.

5.3 Available Data Values
-------------------------

In general any value known inside the calling API can be passed as a read_only
parameter to the custom user hook code. Row who columns and the p_validate
column are exceptions. The standard API naming convention is used. Example:
p_ followed by the database column name. The hooks available for the Row
Handlers are slightly different in terms of the data values available:

After Insert - only column values that can be populated or derived during an
insert are available.

After Update - Two sets of values are available. The new values and the old
values. The values on the updated record can be referenced by
adding p_ prefix to the database column. The values that existed
prior to the update statement can also be referenced by adding
p_ prefix and a _o suffix to the database column name.

After Delete - Only old values with p_ prefix and _o suffix are available.

Old values are not available on Before Process,After Process and After Insert
hooks.

A complete list of parameters available for each hook can be obtained by
running the script $PER_TOP/admin/sql/hrahkpar.sql.

6. Using User Hooks
-------------------

After choosing the type of hook required and the location for it, the hook code
has to be written. It then needs to be registered, and finally the hook package
has to be modified to call it. The example used in this section describes the
implementation of an After Process hook in the CREATE_EMPLOYEE Business Process
API.

6.1 Writing the custom PL/SQL procedure
---------------------------------------

The hook code must be written in a PL/SQL server-side package procedure. The
procedure is always called if registered (unless the main validation logic
errors first), and, any conditional logic must be implemented in the code
and an application error raised if required.

No commits or rollbacks are allowed in the hook procedure. These are always
performed after the API has been called whether it be in a PL/SQL wrapper or
form.

When the PL/SQL package has been created, it must be compiled successfully
on the database.

Fig 1 below illustrates how a user hook can be used to implement some
extra validation on name and nationality. An error is raised if the
validation fails.

Fig 1.
------

create or replace Package scoop_nationality_check as
procedure polish_name_check
(p_last_name in varchar2
,p_nationality in varchar2);
end scoop_nationality_check;
/
Create or Replace Package Body scoop_nationality_check as
procedure polish_name_check
(p_last_name in varchar2
,p_nationality in varchar2)
is
begin
-- When the first name entered is a polish name then check that the
-- nationality entered is Polish
if p_last_name = 'Chrosicka' then
if p_nationality != 'POL' then
dbms_standard.raise_application_error
(num => -20999
,msg => 'Nationality must be Polish');
end if;
end if;
end polish_name_check;
end scoop_nationality_check;
/
exit;

6.2 Registering the User Hook
-----------------------------

The next step is to link the custom package procedure referred to in
section 6.1 to the hook package.

The table that holds this information is HR_API_HOOK_CALLS.

SQL> DESC HR_API_HOOK_CALLS
Name Null? Type
------------------------------- -------- ----
API_HOOK_CALL_ID NOT NULL NUMBER(15)
API_HOOK_ID NOT NULL NUMBER(15)
API_HOOK_CALL_TYPE NOT NULL VARCHAR2(30)
LEGISLATION_CODE VARCHAR2(30)
SEQUENCE NOT NULL NUMBER(15)
ENABLED_FLAG NOT NULL VARCHAR2(30)
CALL_PACKAGE VARCHAR2(30)
CALL_PROCEDURE VARCHAR2(30)
PRE_PROCESSOR_DATE DATE
ENCODED_ERROR VARCHAR2(2000)
STATUS NOT NULL VARCHAR2(30)
OBJECT_VERSION_NUMBER NUMBER(15)
LAST_UPDATE_DATE DATE
LAST_UPDATED_BY NUMBER(15)
LAST_UPDATE_LOGIN NUMBER(15)
CREATED_BY NUMBER(15)
CREATION_DATE DATE

There are 3 special procedures that maintain data in this table. These are

. hr_api_hook_call_api.create_api_hook_call
. hr_api_hook_call_api.update_api_hook_call
. hr_api_hook_call_api.delete_api_hook_call

Fig 2 shows how to register the user hook.

Fig 2.
------

declare

l_api_hook_call_id number;
l_object_version_number number;

begin

hr_api_hook_call_api.create_api_hook_call
(p_validate => false,
p_effective_date => to_date('01-JUL-1999','DD-MON-YYYY'),
p_api_hook_id => 63,
p_api_hook_call_type => 'PP',
p_sequence => 3000,
p_enabled_flag => 'Y',
p_call_package => 'SCOOP_NATIONALITY_CHECK',
p_call_procedure => 'POLISH_NAME_CHECK',
p_api_hook_call_id => l_api_hook_call_id,
p_object_version_number => l_object_version_number);
end;

a. See section 5.1 to get api_hook_id.

b. The hook mechanism only supports calls to package procedures currently
so api_hook_call_type must be PP.

c. Sequence numbers > 2000 are recommended, as sequences < than 2000 are
reserved for Oracle seeded logic which needs to be processed first.
Please note that you can add any number of hooks to the same API, and
order them using the sequence.

Fig 3 shows a call to delete a link.

Fig 3.
------

declare

l_api_hook_call_id number := 2;
l_object_version_number number := 3;

begin

hr_api_hook_call_api.delete_api_hook_call
(p_validate => false,
p_api_hook_call_id => l_api_hook_call_id,
p_object_version_number => l_object_version_number);
end;

The above call is deleting a specific user hook. Please note any changes made to the HR_API_HOOK_CALLS table, be they via the supplied procedures or not,
will only be effective once the pre-processor has been run.


6.3 Running the Pre-Processor
-----------------------------

Adding rows to the HR_API_HOOK_CALLS table by itself is not sufficient to
enable this extra logic to be called. The pre-processor program must be called
first. This will look at the definitions in the table and build another package
body in the database which is known as the hook package body. If successful, the
pre-processor will hard code the calls to the custom package procedures into the
hook package body. If no extra logic is implemented the hook package body is
still created but without any calls to custom procedures.

During upgrades the pre-processor program will be automatically called to create
the hook package bodies.

To run the pre-processor run one of the following commands:

cd $PER_TOP/admin/sql
Log into SQLPLUS as the APPS user
SQL> @hrahkall.sql

or

SQL> @hrahkone.sql

The first script will create all hook package bodies, whilst the second will
create hook package bodies for one API module only, and prompt for that
api_module_id. In the example we have been using this will be 63.

Fig 4 shows the section of code that does the call to the custom procedure
in the package HR_EMPLOYEE_BK1 after the Pre-Processor has been run.

Fig 4.
------

package body HR_EMPLOYEE_BK1 as
/* $Header: peempapi.pkb 110.4 97/08/29 08:40:21 generated ship $ */

-- Code generated by the Oracle HRMS API Hook Pre-processor
-- Created on 99/07/14 12:01:28 (YY/MM/DD HH:MM:SS)
procedure CREATE_EMPLOYEE_A
(P_HIRE_DATE in DATE
,P_BUSINESS_GROUP_ID in NUMBER
,P_LAST_NAME in VARCHAR2
,P_*** in VARCHAR2
,P_PERSON_TYPE_ID in NUMBER
,P_PER_COMMENTS in VARCHAR2
,P_DATE_EMPLOYEE_DATA_VERIFIED in DATE
,P_DATE_OF_BIRTH in DATE
,P_EMAIL_ADDRESS in VARCHAR2
,P_EMPLOYEE_NUMBER in VARCHAR2
,P_EXPENSE_CHECK_SEND_TO_ADDRES in VARCHAR2
,P_FIRST_NAME in VARCHAR2
,P_KNOWN_AS in VARCHAR2
,P_MARITAL_STATUS in VARCHAR2
,P_MIDDLE_NAMES in VARCHAR2
,P_NATIONALITY in VARCHAR2
,P_NATIONAL_IDENTIFIER in VARCHAR2
,P_PREVIOUS_LAST_NAME in VARCHAR2
,P_REGISTERED_DISABLED_FLAG in VARCHAR2
,P_TITLE in VARCHAR2
,P_VENDOR_ID in NUMBER
,P_WORK_TELEPHONE in VARCHAR2
,P_ATTRIBUTE_CATEGORY in VARCHAR2
,P_ATTRIBUTE1 in VARCHAR2
,P_ATTRIBUTE2 in VARCHAR2
...
...
,P_ATTRIBUTE29 in VARCHAR2
,P_ATTRIBUTE30 in VARCHAR2
,P_PER_INFORMATION_CATEGORY in VARCHAR2
,P_PER_INFORMATION1 in VARCHAR2
,P_PER_INFORMATION2 in VARCHAR2
...
...
,P_PER_INFORMATION29 in VARCHAR2
,P_PER_INFORMATION30 in VARCHAR2
,P_BACKGROUND_CHECK_STATUS in VARCHAR2
,P_BACKGROUND_DATE_CHECK in DATE
,P_BLOOD_TYPE in VARCHAR2
,P_CORRESPONDENCE_LANGUAGE in VARCHAR2
,P_FAST_PATH_EMPLOYEE in VARCHAR2
,P_FTE_CAPACITY in NUMBER
,P_HONORS in VARCHAR2
,P_INTERNAL_LOCATION in VARCHAR2
,P_LAST_MEDICAL_TEST_BY in VARCHAR2
,P_LAST_MEDICAL_TEST_DATE in DATE
,P_MAILSTOP in VARCHAR2
,P_OFFICE_NUMBER in VARCHAR2
,P_ON_MILITARY_SERVICE in VARCHAR2
,P_PRE_NAME_ADJUNCT in VARCHAR2
,P_PROJECTED_START_DATE in DATE
,P_RESUME_EXISTS in VARCHAR2
,P_RESUME_LAST_UPDATED in DATE
,P_SECOND_PASSPORT_EXISTS in VARCHAR2
,P_STUDENT_STATUS in VARCHAR2
,P_WORK_SCHEDULE in VARCHAR2
,P_SUFFIX in VARCHAR2
,P_PERSON_ID in NUMBER
,P_ASSIGNMENT_ID in NUMBER
,P_PER_OBJECT_VERSION_NUMBER in NUMBER
,P_ASG_OBJECT_VERSION_NUMBER in NUMBER
,P_PER_EFFECTIVE_START_DATE in DATE
,P_PER_EFFECTIVE_END_DATE in DATE
,P_FULL_NAME in VARCHAR2
,P_PER_COMMENT_ID in NUMBER
,P_ASSIGNMENT_SEQUENCE in NUMBER
,P_ASSIGNMENT_NUMBER in VARCHAR2
,P_NAME_COMBINATION_WARNING in BOOLEAN
,P_ASSIGN_PAYROLL_WARNING in BOOLEAN
)is
l_commit_unit_number number;
l_legislation_code varchar2(30);
begin
hr_utility.set_location('Entering: HR_EMPLOYEE_BK1.CREATE_EMPLOYEE_A', 10);
l_commit_unit_number := hr_api.return_commit_unit;
if hr_api.call_cus_hooks then
SCOOP_NATIONALITY_CHECK.POLISH_NAME_CHECK
(P_LAST_NAME => P_LAST_NAME
,P_NATIONALITY => P_NATIONALITY
);
end if;
hr_api.validate_commit_unit(l_commit_unit_number, 'CREATE_EMPLOYEE', 'AP');
hr_utility.set_location(' Leaving: HR_EMPLOYEE_BK1.CREATE_EMPLOYEE_A', 20);
end CREATE_EMPLOYEE_A;

If you want to disable a custom package procedure, then the API
hr_api_hook_call_api.update_api_hook_call must be executed to set the
p_enabled_flag to N. Afterwards the pre-processor must be run to recreate the
hook package body. To re-enable,set the p_enabled_flag back to Y and re-run
pre-processor.

Similarly if you permanently delete the definition using the delete API
described in section 6.2, you must run the pre-processor afterwards to remove
the hard coded call (see Fig 4) from the hook package body.

If the Pre-Processor errors, it will set the status on HR_API_HOOK_CALLS
to I for Invalid. Status will be V for Valid if successful. If it errors the
message is written to the ENCODED_ERROR column. This can be read using the
following SQL:

declare
l_encoded_error varchar2(2000);
l_user_read_text varchar2(2000);
begin
Substitute ??? with the value held in the
HR_API_HOOK_CALLS.ENCODED_ERROR column.
l_encoded_error := ???;
fnd_message.set_encoded(encoded_error);
l_user_read_text := fnd_message.get;
end;

6.4 Running the Custom Procedure
--------------------------------

Fig 5 shows a call to the create_employee API which inputs data to force the
custom procedure shown in section 6.1 to fail. Fig 6 shows the error message
raised as a result.

Fig 5.
------

declare

l_per_object_version_number number;
l_asg_object_version_number number;
l_person_id number;
l_assignment_id number;
l_per_effective_start_date date;
l_per_effective_end_date date;
l_full_name varchar2(60);
l_per_comment_id number;
l_assignment_sequence number;
l_assignment_number varchar2(30);
l_name_combination_warning boolean;
l_assign_payroll_warning boolean;
l_emp_number varchar2(30);

begin

l_emp_number := '15';

hr_employee_api.create_employee
(p_validate => false
,p_hire_date => to_date('15-jun-1999','dd-mon-yyyy')
,p_business_group_id => 147
,p_last_name => 'Chrosicka'
,p_*** => 'F'
,p_date_of_birth => to_date('15-dec-1975','dd-mon-yyyy')
,p_employee_number => l_emp_number
,p_first_name => 'Ania'
,p_nationality => 'BEL'
,p_person_id => l_person_id
,p_assignment_id => l_assignment_id
,p_per_object_version_number => l_per_object_version_number
,p_asg_object_version_number => l_asg_object_version_number
,p_per_effective_start_date => l_per_effective_start_date
,p_per_effective_end_date => l_per_effective_end_date
,p_full_name => l_full_name
,p_per_comment_id => l_per_comment_id
,p_assignment_sequence => l_assignment_sequence
,p_assignment_number => l_assignment_number
,p_name_combination_warning => l_name_combination_warning
,p_assign_payroll_warning => l_assign_payroll_warning
);
end;

Fig 6.
------

declare
*
ERROR at line 1:
ORA-20999: Nationality must be Polish
ORA-06512: at "APPS.SCOOP_NATIONALITY_CHECK", line 11
ORA-06512: at "APPS.HR_EMPLOYEE_BK1", line 131
ORA-06512: at "APPS.HR_EMPLOYEE_API", line 504
ORA-06512: at line 21

If the error is raised in a form then the following error displays. The detail
displays when clicking on History.

FRM-40735: <trigger name> trigger raised unhandled exception ORA-20999

Detecting whether a reported error is raised by a custom procedure or not may be
a challenging exercise for a support analyst. However, that is usually the case
with any bespoke code. The clues to look for are

a. Familiarity with standard error messages. Is this a standard HRMS
message?

b. The error code may give a clue. Example; if a particular range has been
used to raise application errors in the custom procedure. In this case
ORA-20999. Usually the range 20000 - 20999 are reserved for raising
errors from triggers and packaged procedures.

c. The package reporting the error is the real give away. HR_EMPLOYEE_BK1
is a hook procedure.
saudapk
Posts: 13
Joined: Tue Feb 28, 2012 3:51 pm
Location: Qatar

Post by saudapk »

Hi,
Thank you for your reply.
Actually, for me the issue was not to get how to use or when to use User hooks. I had already created some other userhooks before also.
But here for the specific user hook I referred, I could not register it with the parameter "P_validate" as "True" but can register with the same parameter as "False" and could not find anything in the documents about it also. Anyway, I did some work around for it. But if you know any information about this specific User hook, Please share with us..

Thanks
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