New to ABAP Enhancements

Question

Hi Experts,
         As I am new to ABAP Enhancements can anyone guide with the navigations on how to proceed for creating an enhanced object.I will be helpful if u can provide it with some examples.
Thanks & Regards,
Naresh

Answer 1

Hi,
<i><b>Overview of Customer Exits</b></i>
The SAP application programmer plans possible application enhancements
in an application and defines the necessary components. These
components are combined in SAP enhancements.The programmers document their enhancements as best they can so that customers can implement the enhancements without having to analyze the program source code or the screen source code.
First, create an enhancement project and then choose the SAP
enhancements you want to use.
Next, edit your individual components using the project management
function and document the entire enhancement project.
Finally, activate the enhancement project. This activates all the component
parts of the project.
The transaction, CMOD, starts the project management function. You
must give your enhancement project a name. SAP recommends that you
think up a naming convention for all your projects. You caninclude the
transaction or module pool of the project in its name. All the enhancement
project names must be unique.
Next, go to the attributes of the project and enter a short text describing
the enhancenent project. The system inserts all the other attributes of the
project, such as created by, created on, and or status.
Use the project management function to assign SAP enhancements to
customer enhancement projects. Enter the names of the SAP enhancements
you want to use on the appropriate screen.
The search function gives you a catalog-like overview of existing SAP
enhancements. From there, you can select the enhancements that are of
interest to you.
Use the product management function to edit the components of your
enhancement project.
Depending on whether the component you are editing is a function
module, a menu entry, or a subscreen, you branch to either the Function
Builder, a dialog box for entering menu entries, or to the Screen Painter.
Activation of an enhancement project affects all its components. After it
has been activated successfully, the project has the status, active.
During activation, all programs, screens, and menus that contain the
components that belong to the project are regenerated (programs at the
time they are executed). After activation, you can see the effect of the
enhancements in your application functions.
The Deactivate function allows you to reset the status of an active
enhancement project to inactive.
When the enhancement project was created, you should have assigned
it to a change request. Each of the component pieces, such as include
programs, subscreens, and menu exits, should be assigned to the same
change request. Using the same change request allows you to transport
the entire enhancement at the same time.
<i><b>Function Module Exits</b></i>
Function module exits allow customers to implement additional logic
in application functions. SAP application programmers define where
function module exits are inserted and what type of data they transfer.
SAP programmers also create the corresponding function modules of an
exit complete with short text, interface, and documentation, as well as
describing the intended purpose of each function module in the SAP
documentation.
You write the source code for the function modules yourself. If need be,
you can also create your own screens, text elements, and includes for the
function group.
The system processes your ABAP code when the enhancement project of
which your function module is a component is activated. Function module
exits have no effect prior to enhancement project activation.
The exit function module is called in the PAI logic of a screen at a position
determined by the SAP application developer. Within the function module,
the user can add the functions in the customer namespace using an include.
To call function modules, use the ABAP statement: CALL
CUSTOMER-FUNCTION ’nnn’, where nnn is a three-digit number. The
programmer must also create the function module the developer wants to
call and its related function group.
These function modules always belong to function groups, the names of
which begin with X (X function group).
The following naming convention applies to function modules:
&#149; Prefix:EXIT
&#149; Name: Name of the program that calls the function module
&#149; Suffix: Three-digit number
The three parts of the name are separated by an underscore.
The CALL CUSTOMER-FUNCTION statement is only executed after
the enhancement project has been activated. Multiple calls of the same
function module are all activated at the same time.
The most frequently asked question concerning enhancements is how can
you see if an application program offers a function module exit? There are
a number of ways to find the answer to this question.
To see quickly if an application program offers a function module exit, you
can follow the path on the left side of the figure: The menu path System&#8594;
Status always displays the name of the current application program. In
this example, a suitable character string would be CALL CUSTOMER.
Click the Find icon and search globally in the program. If your search doesnot provide any results, you can define a larger search area. Determine
the environment for the corresponding program and look for the specific
character string in the program environment.
The right side of the figure shows you howto find the name of the required
enhancement using search tools. You can restrict the search in the SAP R/3
Repository Information System using different criteria. These are:
&#149; Development class (also try generic entries)
&#149; Technical name of the enhancement
Use the project management, transaction: CMOD function, to edit the
function modules for function module exits.
Use the button for editing components to go directly to the function
module editor (display mode).
Do not change the function module itself. It is especially important that
you do not alter the interface in any way. The function module, contains
an INCLUDE statement for an include program that you have to create
in the customer namespace.
Select the include name beginning with ZX. This automatically takes you
to the editor of the include program, where you can enter your code.
To understand how an X function group works, you need to understand
how a normal function group works:
&#149; A function group consists of includes. The system assigns unique the
names to the includes for different objects. Some of the include names
are simply proposals and some cannot be changed.
&#149; Global data is stored in the TOP include. This include is generated
automatically when a function group is created.
&#149; Function modules are stored in includes with sequential numbering
and they, in turn, are all stored in an include ending with UXX.
&#149; Although can freely choose the names of the includes for all other
objects such as subroutines, modules, and events, it is a good idea
to accept the proposed names.
Exit function groups created by SAP application programmers for
enhancement exits contain include programs that begin with either LX or
ZX. You can only edit includes beginning with a Z because they are stored
in the customer namespace.
No further function modules may be added to the function group.
The include program, ZxaaaUnn contains the source code for the function
modules of a function module exit.
SAP application programmers can declare global data in include program,
LXaaaTAP.
You can declare your global data in the include, ZXaaaTOP.
Include program, LXaaaTOP also contains the FUNCTION-POOL statement,
which may not be changed. For this reason, you must always include the
message class in parentheses when outputting messages. For example,
MESSAGE E500 (EU) .
The INCLUDE statement for program ZXaaaUnn is in a FUNCTION -
ENDFUNCTION block. Because of this, neither events, nor subroutines(
FORM ), nor modules ( MODULE ) are allowed here. They can be created in
separate includes, which is explained later. Data declarations made here
with DATA are valid locally in this function module.
The SAP application programmer can also make a proposal for the source
text. In this case, an INCLUDE LXaaFnn is created, where nn is the
internal number for the function module in the include, LXaaaUXX ).
Documentation is also provided within the SAP enhancement. You can
copy the source code fromthis include into your own customer include
program, ZxaaaUnn, using the project management transaction.
You can create your own text elements for the function group.
SAP application programmers can supply you with default subroutines
in the include, LXaaaF01.
There could be further includes containing specific subobjects:
&#149; LX...F01 contains the subroutines delivered by SAP
&#149; LX...E01 contains the events belonging to the X function group
&#149; LX...O01 contains the PBO modules for the screens to be delivered
&#149; LX...I01 contains the corresponding PAI modules
Subroutines, modules, and interactive events (AT) are created as include
programs and included enhancements using the include program,
ZXaaaZZZ.
Additional includes must adhere to the following naming convention:
&#149; ZXaaaFnn for subroutines
&#149; ZXaaaOnnforPBOmodules
&#149; ZXaaaInn for PAI modules
&#149; ZXaaaEnn for events
You can use CALL SCREEN to call your own screens. Create the related
include programs for the Process Before Output (PBO) and Process After
Input (PAI) modules in the include program, ZXaaaZZZ .
Use forward navigation (select an object and then double-click it) to create
your own screens and modules.
Screens created in this way are automatically given the name of the
function module&#146;s main program, SAPLXaaa . The PBO modules for these
screens can be found in the include, ZXaaaO01 , and the PAImodules
in the include, ZXaaaI01 .
You can enhance SAP applications by adding your own processing logic
at predefined points.
Such enhancements can include your own screenswith their corresponding
processing logic and graphical user interface as well as text elements
created by customers.
Regards,
Balaji Reddy G
***Rewards if answers are helpful