Urgent pls anser

Question

1) what is the difference between instance method and class method in bapi?
2)what is commit work  and explain?
3)
      Cancel ( )
Unlike the BAPI Delete(), the BAPI Cancel() cancels
an instance of a business object type. The instance
to be cancelled remains in the database and an
additional instance is created and this is the one that
is actually canceled. The Cancel() BAPI is an
instance method.
pls explain the above ? then why do the they cancel it ? what will be the scenario?

Answer 1

Hi,
Look at this example:
<b>Class Definition</b>
*       CLASS main DEFINITION
CLASS main DEFINITION.
  PUBLIC SECTION.
"   This is a Instance method
    METHODS add_data IMPORTING i_data TYPE i.
"   This is a Instance method
    METHODS get_data EXPORTING e_data TYPE char20.
"   This is a Class method
    CLASS-METHODS print IMPORTING value TYPE char20.
  PRIVATE SECTION.
    DATA atribute TYPE char01.
ENDCLASS.
<b>
Class Implementation</b>
*       CLASS main IMPLEMENTATION
CLASS main IMPLEMENTATION.
  METHOD add_data.
    ADD i_data TO atribute.
  ENDMETHOD.
  METHOD get_data.
    CONCATENATE 'Atribute value' atribute
                               INTO r_data SEPARATED BY space.
  ENDMETHOD.
  METHOD print.
    WRITE value.
  ENDMETHOD.
ENDCLASS.
<b>Creation Object</b>
DATA: object_reference  TYPE REF TO main.
DATA: object_reference2 TYPE REF TO main.
/code]
<b>Instance Creation</b>
[code]
" Each instance  has its methods
CREATE OBJECT object_reference.
CREATE OBJECT object_reference2.
<b>
Calling Methods</b>
"The Instance method add_data( ) needs to be acessed by a instance
CALL METHOD object_reference->add_data( i_data = 3 ).
"The Instance method get_data(  ) needs to be acessed by a instance
var = object_reference->get_data(  ).
"The Class method print( ) doen't needs to be acessed by a instance
" In this case you can acess by own class
CALL METHOD main=>print EXPORTING value = var.
For more information see:
<a href="/people/dirk.feeken/blog/2007/07/06/abap-trial-version-for-newbies-part-17--your-first-abap-object Trial Version for Newbies: Part 17 - Your first ABAP Object</a>
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/1591ec90-0201-0010-3ba8-cdcd500b17cf">ABAP Code Sample for Objects</a>
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/2503f09c-0801-0010-dc89-80bab376e4b8">Object Oriented ABAP - Local and Global classes</a>
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/b6cae890-0201-0010-ef8b-f970a9c41d47">ABAP Code Sample to Learn Basic Concept of Object-Oriented Programming</a>
<a href="https://sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sap.km.cm.docs/library/uuid/37c5db90-0201-0010-3a9b-d0a5288f3c15">Eight Reasons Why Every ABAP Developer Should Give ABAP Objects a Second Look</a>
<a href="https://sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sap.km.cm.docs/library/uuid/3e59b790-0201-0010-88aa-bc8a7f95f6fb">Why use ABAP Objects</a>
<a href="https://media.sdn.sap.com/public/eclasses/teched04/ABAP151_files/Default.htm#nopreload=1">ABAP Objects for Java Developers</a>
Also look this Wiki page:
<a href="https://wiki.sdn.sap.com/wiki/display/ABAP/ABAP+Objects">ABAP Objects Wiki Page</a>
Regards.
Marcelo Ramos