Abap Objects

ABAP Objects Workshop

Vinitha Rajan Intelligroup Asia Ltd.  Intelligroup Asia Ltd., Technology Team

 SAP AG

Topics Covered

 Object orientation  Objects & Object References  ABAP Objects

 Intelligroup Asia Ltd., Technology Team

Object Orientation

Data

Data

Data

Attributes Data

Data

Data

Abstraction Function

Methods Function Function

Function

Method Method Method

Function Function Function Function

Functions and data Data model as an abstraction of the real world

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Software objects Object model as an abstraction of the real world

Real-world objects

Objects & Object References

Interface Private components



Airline Flight number

Flight

Private access

Customer

Address



Passengerlist

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Public methods BOOK



FLIGHT

Public attributes

Public events

Public access

ABAP Objects

 ABAP Objects is an upwards-compatible extension of the existing ABAP language  You can use existing ABAP statements within ABAP Objects  You can use ABAP Objects within existing programs  ABAP Objects is fully integrated in the ABAP Debugger

 Intelligroup Asia Ltd., Technology Team

From Function Groups to Classes

 Instances of function groups as objects  Example: Function group as counter

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Instances of Function Groups as Objects

Function group 1

Function module …

Function group 2

Data

Function module

Data

…

ABAP program with data CALL FUNCTION ... Internal session of an ABAP program External session

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Function Group as Counter - Definition

FUNCTION-POOL COUNTER. DATA COUNT TYPE I. FUNCTION SET_COUNTER. * Local Interface IMPORTING VALUE(SET_VALUE) COUNT = SET_VALUE. ENDFUNCTION. FUNCTION INCREMENT_COUNTER. COUNT = COUNT + 1. ENDFUNCTION. FUNCTION GET_COUNTER. * Local Interface: EXPORTING VALUE(GET_VALUE) GET_VALUE = COUNT. ENDFUNCTION.

 Intelligroup Asia Ltd., Technology Team

Function Group as Counter - Call

DATA NUMBER TYPE I VALUE 5. CALL FUNCTION 'SET_COUNTER' EXPORTING SET_VALUE = NUMBER. DO 3 TIMES. CALL FUNCTION 'INCREMENT_COUNTER'. ENDDO. CALL FUNCTION 'GET_COUNTER' IMPORTING GET_VALUE = NUMBER.

NUMBER has value 8

 Intelligroup Asia Ltd., Technology Team

Classes Generalize Function Groups

nth instance, class m 1st instance, class m

nth instance, class 1 1st instance, class 1

Daten Interface Data Interface Data

Daten Interface Data Interface Data

...

...

...

...

…

…

…

…

ABAP program with data Internal session of an ABAP program External session

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Classes, References, and Objects

 Example: Class as counter  Reference variables  Creating objects  Calling methods  Working with references

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Example: Class as Counter

CLASS counter DEFINITION. PUBLIC SECTION. METHODS: set IMPORTING VALUE(set_value) TYPE i, increment, get EXPORTING VALUE(get_value) TYPE i. PRIVATE SECTION. DATA count TYPE i. ENDCLASS. CLASS counter IMPLEMENTATION. METHOD set. count = set_value. ENDMETHOD. METHOD increment. count = count + 1. ENDMETHOD. METHOD get. get_value = count. ENDMETHOD. ENDCLASS.  Intelligroup Asia Ltd., Technology Team

Reference Variables

DATA: cnt_1 TYPE REF TO counter.

CNT_1  Intelligroup Asia Ltd., Technology Team

Creating an Object

DATA: cnt_1 TYPE REF TO counter.

CREATE OBJECT cnt_1 TYPE counter.

1

CNT_1  Intelligroup Asia Ltd., Technology Team

Calling Methods

DATA: cnt_1 TYPE REF TO counter. DATA number TYPE I VALUE 5. CREATE OBJECT cnt_1 TYPE counter. CALL METHOD cnt_1->set EXPORTING set_value = number. DO 3 TIMES. CALL METHOD cnt_1->increment. ENDDO. 1

CALL METHOD cnt_1->get IMPORTING get_value = number.

NUMBER has the value 8  Intelligroup Asia Ltd., Technology Team

CNT_1

Several Reference Variables

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter.

CNT_3 CNT_2 CNT_1  Intelligroup Asia Ltd., Technology Team

Several Objects

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1, cnt_2. 2

1

CNT_3 CNT_2 CNT_1  Intelligroup Asia Ltd., Technology Team

Assigning Reference Variables

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1, cnt_2.

2

MOVE cnt_2 TO cnt_3.

1

CNT_3 CNT_2 CNT_1  Intelligroup Asia Ltd., Technology Team

Deleting Reference Variables

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1, cnt_2. MOVE cnt_2 TO cnt_3. CLEAR cnt_2.

2 1 CNT_3 CNT_2 CNT_1

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Garbage Collection

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1, cnt_2.

2

MOVE cnt_2 TO cnt_3. CLEAR cnt_2. cnt_3 = cnt_1.

1

CNT_3 CNT_2 CNT_1  Intelligroup Asia Ltd., Technology Team

Garbage Collection

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1, cnt_2. MOVE cnt_2 TO cnt_3.

2

CLEAR cnt_2. cnt_3 = cnt_1.

1

CLEAR cnt_3. CNT_3 CNT_2 CNT_1  Intelligroup Asia Ltd., Technology Team

New Objects

DATA: cnt_1 TYPE REF TO counter,

3

cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1,

2

cnt_2. MOVE cnt_2 TO cnt_3. CLEAR cnt_2.

1

cnt_3 = cnt_1. CLEAR cnt_3. CREATE OBJECT: cnt_2, cnt_3.

CNT_3 CNT_2 CNT_1

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Example: Class Identity

CLASS counter DEFINITION. PUBLIC SECTION. METHODS: set IMPORTING VALUE(set_value) TYPE i, increment, get EXPORTING VALUE(get_value) TYPE i. PUBLIC SECTION. DATA count TYPE i. ENDCLASS. CLASS counter IMPLEMENTATION. METHOD set. count = set_value. ENDMETHOD. METHOD increment. count = count + 1. ENDMETHOD. METHOD get. get_value = count. ENDMETHOD. ENDCLASS.  Intelligroup Asia Ltd., Technology Team

Identity

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter, cnt_3 TYPE REF TO counter. DATA number TYPE I VALUE 5. CREATE OBJECT: cnt_1, 2

cnt_2. CALL METHOD cnt_1->set EXPORTING set_value = number. CALL METHOD cnt_2->set EXPORTING set_value = number. * Reference Semantics If cnt_1 = cnt_2. * This will not be executed endif  Intelligroup Asia Ltd., Technology Team

1

CNT_3 CNT_2 CNT_1

Identity (Contd.)

* Attribute values are the same!!! If cnt_1->count = cnt_2->count. * This will be executed

2

Endif cnt_3 = cnt_1 If cnt_3 = cnt_1.

1

* This will be executed Endif.

CNT_3 CNT_2 CNT_1

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Methods of Several Objects

DATA: cnt_1 TYPE REF TO counter, cnt_2 TYPE REF TO counter,

3

cnt_3 TYPE REF TO counter. CREATE OBJECT: cnt_1, cnt_2,

2

cnt_3. CALL METHOD cnt_1->set EXPORTING set_value = 1. CALL METHOD cnt_2->set EXPORTING set_value = 10. CALL METHOD cnt_3->set EXPORTING set_value = 100.

1

CNT_3 CNT_2

The value of COUNT is different in each object  Intelligroup Asia Ltd., Technology Team

CNT_1

Objects: Summary

 Declaring reference variables DATA: ref1 TYPE REF TO class, ref2 TYPE REF TO class.

 Creating objects CREATE OBJECT: ref1, ref2.

 Accessing attributes and methods x = ref1->attr + ref2->attr. CALL METHOD ref1->method EXPORTING ...

 Object References and identities

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