What are BADIs in SAP ?.?

Answer 1

Business Add ins are extra functions.
Check the sap help portal:

http://help.sap.com/saphelp_erp2005/helpdata/en/c2/eab541c5b63031e10000000a155106/frameset.htm

Function documentation Definition of BAdIs Locate the document in its SAP Library structure
Use

When you define a BAdI, you must specify a name, a BAdI interface as the interface for the enhancement option, and the required filters. The name of a BAdI is in the same namespace as data types from the ABAP Dictionary, global classes, or interfaces. It is recommended that you use suitable prefixes, such as “BADI_”.

A filter consists of a filter name and a data type (integer, string, and so on).

In addition, you also define BAdI properties that are relevant at runtime of a program with the appropriate statements GET BADI and CALL BADI. For more information, see Instance Generation Mode and Multiple Use.

Other properties that can be assigned to a BAdI include:

● An optional fallback BAdI implementation class. This option is used if no BAdI implementation with suitable filter conditions and no standard implementation is found.

● Whether the BAdI is internal or not.

Caution

An internal BAdI must only be implemented by SAP and is not visible outside of SAP.

● Whether the BAdI is a function code or screen enhancement.

A BAdI that is defined as a function code enhancement must not have any filters, must not be defined for multiple use, or assigned to any switch. It may contain methods that are independent of the actual function code enhancement.

A BAdI that is defined as a screen enhancement must be defined in the instance generation mode for the reused instantiation and must not be defined for multiple use. It may contain BAdI methods that can be used to fill or evaluate the screen fields of the respective subscreens.

See also:

Definition of BAdIs in the Enhancement Builder