Oop concepts in ABAP

http://scn.sap.com/docs/DOC-10236 e-learning Link to learn OOP Basics

Public attributes

Public attributes are defined in the PUBLIC section and can be viewed and changed from outside the class. There is direct access to public attributes. As a general rule, as few public attributes should be defined as possible.

PUBLIC SECTION.

DATA: Counter type i.

Private attributes

Private attributes are defined in the PRIVATE section. The can only be viewed and changed from within the class. There is no direct access from outside the class.

PRIVATE SECTION.

DATA: name(25) TYPE c,

planetype LIKE saplane-planetyp,

Instance attributes

There exist one instance attribute for each instance of the class, thus they exist seperately for each object. Instance attributes are declared with the DATA keyword.

Static attributes

Static attributes exist only once for each class. The data are the same for all instances of the class, and can be used e.g. for instance counters. Static attributes are defined with the keyword CLASS-DATA.

PRIVATE SECTION.

CLASS-DATA: counter type i, Public methods

Can called from outside the class

PUBLIC SECTION.

METHODS: set_attributes IMPORTING p_name(25) TYPE c,

p_planetype LIKE saplane-planetyp,

Private methods

Can only be called from inside the class. They are placed in the PRIVATE section of the class.

Constructor method

Implicitly, each class has an instance constructor method with the reserved name constructor and a static constructor method with the reserved name class_constructor.

The instance constructor is executed each time you create an object (instance) with the CREATE OBJECT statement, while the class constructor is executed exactly once before you first access a class.

The constructors are always present. However, to implement a constructor you must declare it explicitly with the METHODS or CLASS-METHODS statements. An instance constructor can have IMPORTING parameters and exceptions. You must pass all non-optional parameters when creating an object. Static constructors have no parameters.

Static constructor

The static constructor is always called CLASS_CONSTRUCTER, and is called automatically before the class is first accessed, that is before any of the following actions are executed:

Creating an instance using CREATE_OBJECT

Addressing a static attribute using ->

Calling a static attribute using CALL METHOD

Registering a static event handler

Registering an event handler method for a static event

The static constructor cannot be called explicitly.

Protected components

When we are talking subclassing and inheritance there is one more component than Public and Private, the Protected component. Protected components can be used by the superclass and all of the subclasses. Note that Subclasses cannot access Private components.

Polymorphism

Polymorphism: When the same method is implemented differently in different classes. This can be done using inheritance, by redefining a method from the superclass in subclasses and implement it differently.

Template for making a classDelete the parts that should not be used

******************************************

* Definition part

******************************************CLASS xxx DEFINITION.

*------------------------------

* Public section

*------------------------------

PUBLIC SECTION.

TYPES:

DATA:

* Static data CLASS-DATA:

* Methods METHODS:

* Using the constructor to initialize parameters constructor IMPORTING xxx type yyy,

* Method with parameters mm1 IMPORTING iii TYPE ttt.

* Method without parameters mm2.

* Static methods CLASS-METHODS:

*---------------------------------------------------*

* Protected section. Also accessible by subclasses

*---------------------------------------------------

PROTECTED SECTION.

*---------------------------------------------------

* Private section. Not accessible by subclasses

*---------------------------------------------------

PRIVATE SECTION.

ENDCLASS.

******************************************

* Implementation part

******************************************

CLASS lcl_airplane IMPLEMENTATION.

METHOD constructor.

ENDMETHOD.

METHOD mm1.

ENDMETHOD.

METHOD mm2.

ENDMETHOD.

ENDCLASS.

Template for calling a class* Create reference to class lcl_airplaneDATA: airplane1 TYPE REF TO lcl_airplane.

START-OF-SELECTION.

* Create instance using parameters in the cosntructor method CREATE OBJECT airplane1 exporting im_name = 'Hansemand'

im_planetype = 'Boing 747'.

* Calling a method with parameters CALL METHOD: airplane1->display_n_o_airplanes,

airplane1->display_attributes.

SubclassCLASS xxx DEFINITION INHERITING FROM yyy.Using af class as a parameter for a methodThe class LCL_AIRPLANE is used as a parameter for method add_a_new_airplane:METHODS:

add_a_new_airplane importing im_airplane TYPE REF to lcl_airplane.InterfacesIn ABAP interfaces are implemented in addition to, and independently of classes. An interface only has a declaration part, and do not have visibillity sections. Components (Attributes, methods, constants, types) can be defined the same way as in classes. Interfaces are listed in the definition part of the class, and must always be in the PUBLIC SECTION. Operations defined in the interface are implemented as methods of the class. All methods of the interface must be present in the

implementation part of the class. Attributes, events, constants and types defined in the interface are automatically available to the class carrying out the implementation. Interface components are addressed in the class by ~

Example of how to implement an interface:INTERFACE lif_document DATA: author type ref to lcl_author. METHODS: print, display.ENDINTERFACE.CLASS lcl_text_document DEFINITION.

PUBLIC SECTION.

INTERFACES lif_document. METHODS display.

ENDCLASS.CLASS lcl_text_document IMPLEMENTTION. METHOD lif_document~print.

ENDMETHOD.

METHOD lif_document~display ENDMETHOD.

METHOD display.

ENDMETHOD.

ENDCLASS.REPORT zzz. DATA: text_doc TYPE REF TO lcl_document. Start-of-selection.

CREATE OBJECT text_doc. CALL METHOD text_doc->lif_document~print.

CALL METHOD text_doc->lif_document~display.

CALL METHOD text_doc->display.

Events For events of controls, refer to How to use controls. Events can only have EXPORTING parameters When an event is triggered, only those events handlers that have registered themselves using SET HANDLER by this point of runtime are

executed. You can register an event using ACTIVATION 'X' and deregert it by using ACTIVATION 'SPACE'.Defining events:CLASS DEFINITION. EVENTS: EXPORTING VALUE () TYPE type.CLASS IMPLEMENTATION.

METHOD :

RAISE EVENT EXPORTING = .Handling events:CLASS DEFINITION.

METHODS: FOR OF ! IMPORTING ... SENDER.Setting handler SET HANDLER FOR ! FOR ALL INSTANCES

[ACTIVATION ]Define, implement and use simple class***INCLUDE ZBC404_HF_LCL_AIRPLANE .******************************************

* Definition part

******************************************

CLASS lcl_airplane DEFINITION.

*------------------------------

* Public section

*------------------------------

PUBLIC SECTION.

TYPES: t_name(25) TYPE c.

METHODS:

constructor,

set_attributes IMPORTING p_name TYPE t_name

p_planetype TYPE saplane-planetype,

display_attributes,

display_n_o_airplanes.

*------------------------------

* Private section

*------------------------------

PRIVATE SECTION.

* Private attributes DATA: name(25) TYPE c,

planetype TYPE saplane-planetype.

* Private static attribute CLASS-DATA n_o_airplanes TYPE i.

ENDCLASS.

******************************************


******************************************CLASS lcl_airplane IMPLEMENTATION.

METHOD constructor.

* Counts number of instances n_o_airplanes = n_o_airplanes + 1.

ENDMETHOD.

METHOD set_attributes.

name = p_name.

planetype = p_planetype.

ENDMETHOD.

METHOD display_attributes.

WRITE:/ 'Name:', name, 'Planetype:', planetype.

ENDMETHOD.

METHOD display_n_o_airplanes.

WRITE: / 'No. planes:', n_o_airplanes.

ENDMETHOD.

ENDCLASS.

REPORT zbc404_hf_maintain_airplanes .INCLUDE zbc404_hf_lcl_airplane.

* Create reference to class lcl_airplaneDATA: airplane1 TYPE REF TO lcl_airplane,

airplane2 TYPE REF TO lcl_airplane.

START-OF-SELECTION.

* Create instance CREATE OBJECT airplane1.

CALL METHOD: airplane1->display_n_o_airplanes.

CREATE OBJECT airplane2.

* Setting attributes using a method with parameters CALL METHOD airplane1->set_attributes EXPORTING p_name = 'Kurt'

p_planetype = 'MD80'.

END-OF-SELECTION.

* Using methods

CALL METHOD: airplane1->display_n_o_airplanes,

airplane1->display_attributes.

The resulting report:Maintain airplanes

No. planes: 1

No. planes: 2

Name: Kurt Planetype: MD80

Use constructor to create an object with parametersCLASS lcl_airplane DEFINITION.

PUBLIC SECTION.


METHODS:

constructor importing p2_name type t_name

p2_planetype TYPE saplane-planetype,

..... more code .......


METHOD constructor.

name = p2_name.

planetype = p2_planetype.

..... more code .......

START-OF-SELECTION.

CREATE OBJECT airplane1 exporting p2_name = 'Hansemand'

p2_planetype = 'Boing 747'.Sub classingThis example uses a superclass LCL_AIRPLANE and subclasses it into LCL_PASSENGER_AIRPLANE and LCL_CARGO_PLANE.

LCL_AIRPLANE has a method display_n_o_airplanes that displays the number of object instances.

LCL_PASSENGER_AIRPLANE has the private instance attribute n_o_seats, and redefines the superclass method display_attributes, so it also displays n_o_seats.LCL_CARGO_PLANE has the private instance attribute cargomax, and redefines the superclass method display_attributes, so it also displays cargomax.All instance attributes are provided by the constructor method.

Superclass LCL_AIRPLANE***INCLUDE ZBC404_HF_LCL_AIRPLANE .

******************************************

* Definition part

******************************************

CLASS lcl_airplane DEFINITION.*------------------------------

* Public section

*------------------------------

PUBLIC SECTION.


METHODS:

constructor IMPORTING im_name TYPE t_name

im_planetype TYPE saplane-planetype,

display_attributes.

* Static methods CLASS-METHODS:

display_n_o_airplanes.

*------------------------------

* Protected section

*------------------------------

PROTECTED SECTION.

* Private attributes DATA: name(25) TYPE c,

planetype TYPE saplane-planetype.

* Private static attribute CLASS-DATA n_o_airplanes TYPE i.

ENDCLASS.

******************************************


******************************************


METHOD constructor.

name = im_name.

planetype = im_planetype.

* Counts number of instances n_o_airplanes = n_o_airplanes + 1.

ENDMETHOD.


WRITE:/ 'Name:', name, 'Planetype:', planetype.

ENDMETHOD.

METHOD display_n_o_airplanes.

WRITE: / 'No. planes:', n_o_airplanes.

ENDMETHOD.

ENDCLASS.Sub class LCL_PASSENGER_AIRPLANE***INCLUDE ZBC404_HF_LCL_PASSENGER_PLANE .

*******************************************************************

* This is a subclass of class lcl_airplane

*******************************************************************

CLASS lcl_passenger_airplane DEFINITION INHERITING FROM lcl_airplane. PUBLIC SECTION.

* The constructor contains the parameters from the superclass

* plus the parameters from the subclass

METHODS:


im_planetype TYPE saplane-planetype

im_n_o_seats TYPE sflight-seatsmax,

* Redefinition of superclass method display_attributes display_attributes REDEFINITION.

PRIVATE SECTION.

DATA: n_o_seats TYPE sflight-seatsmax.

ENDCLASS.CLASS lcl_passenger_airplane IMPLEMENTATION. METHOD constructor.

* The constructor method of the superclass MUST be called withing the

* constructor

CALL METHOD super->constructor

EXPORTING im_name = im_name

im_planetype = im_planetype.

n_o_seats = im_n_o_seats.

ENDMETHOD.

* The redefined display_attributes method METHOD display_attributes.

CALL METHOD super->display_attributes.

WRITE: / 'No. seats:', n_o_seats.

ENDMETHOD.

ENDCLASS.Sub class LCL_CARGO_PLANE***INCLUDE ZBC404_HF_LCL_CARGO_PLANE .

*******************************************************************

* This is a subclass of class lcl_airplane

*******************************************************************

CLASS lcl_cargo_plane DEFINITION INHERITING FROM lcl_airplane. PUBLIC SECTION.

METHODS:

* The constructor contains the parameters from the superclass

* plus the parameters from the subclass


im_planetype TYPE saplane-planetype

im_cargomax type scplane-cargomax,

* Redefinition of superclass method display_attributes display_attributes REDEFINITION.

PRIVATE SECTION.

DATA:cargomax TYPE scplane-cargomax.

ENDCLASS.CLASS lcl_cargo_plane IMPLEMENTATION. METHOD constructor.

* The constructor method of the superclass MUST be called withing the

* constructor CALL METHOD super->constructor

EXPORTING im_name = im_name

im_planetype = im_planetype.

cargomax = im_cargomax.

ENDMETHOD.


* The redefined display_attributes method CALL METHOD super->display_attributes.

WRITE: / 'Cargo max:', cargomax.

ENDMETHOD.

ENDCLASS.

The Main program that uses the classesREPORT zbc404_hf_main .

* Super classINCLUDE zbc404_hf_lcl_airplane.

* Sub classesINCLUDE zbc404_hf_lcl_passenger_plane.

INCLUDE zbc404_hf_lcl_cargo_plane.

DATA:

* Type ref to sub classes. Note: It is not necesssary to make typeref to the superclass o_passenger_airplane TYPE REF TO lcl_passenger_airplane,

o_cargo_plane TYPE REF TO lcl_cargo_plane.

START-OF-SELECTION.

* Display initial number of instances = 0

CALL METHOD lcl_airplane=>display_n_o_airplanes.

* Create objects CREATE OBJECT o_passenger_airplane

EXPORTING

im_name = 'LH505'

im_planetype = 'Boing 747'

im_n_o_seats = 350.

CREATE OBJECT o_cargo_plane

EXPORTING

im_name = 'AR13'

im_planetype = 'DC 3'

im_cargomax = 35.

* Display attributes CALL METHOD o_passenger_airplane->display_attributes.

CALL METHOD o_cargo_plane->display_attributes.

* Call static method display_n_o_airplanes* Note: The syntax for calling a superclass method, differs from the syntax when calling a subclass method.* When calling a superclass => must be used instead of ->

CALL METHOD lcl_airplane=>display_n_o_airplanes.

Result:No. planes: 0 Name: LH505 Planetype: Boing 747 No. seats: 350 Name: AR13 Planetype: DC 3 Cargo max: 35,0000 No. planes: 2

PolymorphismPolymorphism: When the same method is implemented differently in different classes. This can be done using inheritance, by redefining a method from the superclass in subclasses and implement it differently.

Classes:

lcl_airplane Superclass

lcl_cargo_airplane Subclass

lcl_passenger_airplane Subclass

The method estimate_fuel_consumption is implemented differently in the 3 classes, as it depends on the airplane type.

Object from different classes are stored in an internal table (plane_list) consisting of references to the superclass, and they processed

Identically for all the classes.

What coding for the estimate_fuel_consumption method that is actually executed, depends on the dynamic type of the plane reference variable,

that is, depends on which object plane points to.

DATA: cargo_plane TYPE REF to lcl_cargo_airplane,

passenger_plane TYPE REF to lcl_passenger_airplane,

plane_list TYPE TABLE OF REF TO lcl_airplane.* Creating the list of references

CREATE OBJECT cargo_plane.

APPEND cargo_plane to plane_list.

CREATE OBJECT passenger_plane

APPEND passenger_plane to plane list.

* Generic method for calculating required fuelMETHOD calculate required_fuel.

DATA: plane TYPE REF TO lcl_airplane.

LOOP AT plane_list INTO plane.

re_fuel = re_fuel + plane->estimate_fuel_consumption( distance ).

ENDLOOP.

ENDMETHOD.

Working example:This example assumes that the classes lcl_airplane, lcl_passnger_airplane and lcl_cargo plane (Se Subcallsing) exists.Create objects of type lcl_cargo_plane and lcl_passenger_airplane, adds them to a list in lcl_carrier, and displays the list. *&---------------------------------------------------------------------*

*& Include ZBC404_HF_LCL_CARRIER *

*& *

*&---------------------------------------------------------------------*

* CLASS lcl_carrier DEFINITION *

*----------------------------------------------------------------------*

CLASS lcl_carrier DEFINITION. PUBLIC SECTION.

TYPES: BEGIN OF flight_list_type,

connid TYPE sflight-connid,

fldate TYPE sflight-fldate,

airplane TYPE REF TO lcl_airplane,

seatsocc TYPE sflight-seatsocc,

cargo(5) TYPE p DECIMALS 3,

END OF flight_list_type.

METHODS: constructor IMPORTING im_name TYPE string,

get_name RETURNING value(ex_name) TYPE string,

add_a_new_airplane IMPORTING

im_airplane TYPE REF TO lcl_airplane,

create_a_new_flight importing

im_connid type sflight-connid

im_fldate type sflight-fldate

im_airplane type ref to lcl_airplane

im_seatsocc type sflight-seatsocc

optional

im_cargo type p optional,

display_airplanes.

PRIVATE SECTION.

DATA: name TYPE string,

list_of_airplanes TYPE TABLE OF REF TO lcl_airplane,

list_of_flights TYPE TABLE OF flight_list_type.

ENDCLASS.*---------------------------------------------------------------------*

* CLASS lcl_carrier IMPLEMENTATION

*---------------------------------------------------------------------*

CLASS lcl_carrier IMPLEMENTATION. METHOD constructor.

name = im_name.

ENDMETHOD.

METHOD get_name.

ex_name = name.

ENDMETHOD.

METHOD create_a_new_flight.

DATA: wa_list_of_flights TYPE flight_list_type.

wa_list_of_flights-connid = im_connid.

wa_list_of_flights-fldate = im_fldate.

wa_list_of_flights-airplane = im_airplane.

IF im_seatsocc IS INITIAL.

wa_list_of_flights-cargo = im_cargo.

ELSE.

wa_list_of_flights-seatsocc = im_seatsocc.

ENDIF.

APPEND wa_list_of_flights TO list_of_flights.

ENDMETHOD.

METHOD add_a_new_airplane.

APPEND im_airplane TO list_of_airplanes.

ENDMETHOD.

METHOD display_airplanes.

DATA: l_airplane TYPE REF TO lcl_airplane.

LOOP AT list_of_airplanes INTO l_airplane.

CALL METHOD l_airplane->display_attributes.

ENDLOOP.

ENDMETHOD.

ENDCLASS.

REPORT zbc404_hf_main .*******************************************************************

* This reprort uses class LCL_AIRPLNAE and subclasses

* LCL_CARGO_PLANE and LCL_PASSENGER_AIRPLANE and class LCL_CARRIER

******************************************************************** Super class for airplanesINCLUDE zbc404_hf_lcl_airplane.

* Sub classes for airplanesINCLUDE zbc404_hf_lcl_passenger_plane.

INCLUDE zbc404_hf_lcl_cargo_plane.

* Carrier classINCLUDE zbc404_hf_lcl_carrier.

DATA:

* Type ref to classes o_passenger_airplane TYPE REF TO lcl_passenger_airplane,

o_passenger_airplane2 TYPE REF TO lcl_passenger_airplane,

o_cargo_plane TYPE REF TO lcl_cargo_plane,

o_cargo_plane2 TYPE REF TO lcl_cargo_plane,

o_carrier TYPE REF TO lcl_carrier.

START-OF-SELECTION.

* Create objects CREATE OBJECT o_passenger_airplane

EXPORTING

im_name = 'LH505'

im_planetype = 'Boing 747'

im_n_o_seats = 350.

CREATE OBJECT o_passenger_airplane2

EXPORTING

im_name = 'SK333'

im_planetype = 'MD80'

im_n_o_seats = 110.

CREATE OBJECT o_cargo_plane

EXPORTING

im_name = 'AR13'

im_planetype = 'DC 3'

im_cargomax = 35.

CREATE OBJECT o_cargo_plane2

EXPORTING

im_name = 'AFL124'

im_planetype = 'Iljutsin 2'

im_cargomax = 35000.

CREATE OBJECT o_carrier

EXPORTING im_name = 'Spritisch Airways'.

* Add passenger and cargo planes to the list of airplanes CALL METHOD o_carrier->add_a_new_airplane

EXPORTING im_airplane = o_passenger_airplane.

CALL METHOD o_carrier->add_a_new_airplane

EXPORTING im_airplane = o_passenger_airplane2.


EXPORTING im_airplane = o_cargo_plane.


EXPORTING im_airplane = o_cargo_plane2.

* Display list of airplanes

call method o_carrier->display_airplanes.

Result:Name: LH505 Planetype: Boing 747

No. seats: 350

Name: SK333 Planetype: MD80

No. seats: 110

Name: AR13 Planetype: DC 3

Cargo max: 35,0000

Name: AFL124 Planetype: Iljutsin 2

Cargo max: 35.000,0000

Events Below is a simple example of how to implement an event.

REPORT zbc404_hf_events_5.

*---------------------------------------------------------------------*

* CLASS lcl_dog DEFINITION

*---------------------------------------------------------------------*

CLASS lcl_dog DEFINITION. PUBLIC SECTION.

* Declare events EVENTS:

dog_is_hungry

EXPORTING value(ex_time_since_last_meal) TYPE i.

METHODS:

constructor

IMPORTING im_name TYPE string,

set_time_since_last_meal

IMPORTING im_time TYPE i,

on_dog_is_hungry FOR EVENT dog_is_hungry OF lcl_dog

IMPORTING ex_time_since_last_meal.

ENDCLASS.*---------------------------------------------------------------------*

* CLASS lcl_dog IMPLEMENTATION

*---------------------------------------------------------------------*CLASS lcl_dog IMPLEMENTATION. METHOD constructor.

WRITE: / 'I am a dog and my name is', im_name.

ENDMETHOD.

METHOD set_time_since_last_meal.

IF im_time < 4.

SKIP 1.

WRITE: / 'You fool, I am not hungry yet'.

ELSE.

* Subsrcribe for event:

* set handler

* FOR !FOR ALL INSTANCES [ACTIVATION ] SET HANDLER on_dog_is_hungry FOR ALL INSTANCES ACTIVATION 'X'.

* Raise event RAISE EVENT dog_is_hungry

EXPORTING ex_time_since_last_meal = im_time.

ENDIF.

ENDMETHOD.

METHOD on_dog_is_hungry.

* Event method, called when the event dog_is_hungry is raised SKIP 1.

WRITE: / 'You son of a bitch. I have not eaten for more than',

ex_time_since_last_meal, ' hours'.

WRITE: / 'Give me something to eat NOW!'.

ENDMETHOD.

ENDCLASS.*---------------------------------------------------------------------*

* R E P O R T

*---------------------------------------------------------------------*DATA: o_dog1 TYPE REF TO lcl_dog.

START-OF-SELECTION.

CREATE OBJECT o_dog1 EXPORTING im_name = 'Beefeater'.

CALL METHOD o_dog1->set_time_since_last_meal

EXPORTING im_time = 2.

* This method call will raise the event dog_is_hungy

* because time > 3

CALL METHOD o_dog1->set_time_since_last_meal

EXPORTING im_time = 5.

Result:I am a dog and my name is Beefeater

You fool, I am not hungry yet

You son of a bitch. I have not eaten for more than 5 hours Give me something to eat NOW!

1. Simple classThis example shows how to create a simple employee class. The constructor method is used to initialize number and name of the employee when the object is created. A display_employee method can be called to show the attributes of the employee, and CLASS-METHOD display_no_of_employees can be called to show the total number of employees (Number of instances of the employee class).

REPORT zbc404_hf_events_1.

*********************************************************************

* L C L _ E M P L O Y E E

**********************************************************************---- LCL Employee - DefinitionCLASS lcl_employee DEFINITION.

PUBLIC SECTION.

*--------------------------------------------------------------------

* The public section is accessible from outside

*-------------------------------------------------------------------- TYPES:

BEGIN OF t_employee,

no TYPE i,

name TYPE string,

END OF t_employee.

METHODS:

constructor

IMPORTING im_employee_no TYPE i

im_employee_name TYPE string,

display_employee.

* Class methods are global for all instances CLASS-METHODS: display_no_of_employees.

PROTECTED SECTION.

*--------------------------------------------------------------------

* The protected section is accessible from the class and its subclasses

*--------------------------------------------------------------------* Class data are global for all instances

CLASS-DATA: g_no_of_employees TYPE i.

PRIVATE SECTION.

*--------------------------------------------------------------------

* The private section is only accesible from within the classs

*--------------------------------------------------------------------

DATA: g_employee TYPE t_employee.

ENDCLASS.

*--- LCL Employee - ImplementationCLASS lcl_employee IMPLEMENTATION.

METHOD constructor.

g_employee-no = im_employee_no.

g_employee-name = im_employee_name.

g_no_of_employees = g_no_of_employees + 1.

ENDMETHOD.

METHOD display_employee.

WRITE:/ 'Employee', g_employee-no, g_employee-name.

ENDMETHOD.

METHOD display_no_of_employees.

WRITE: / 'Number of employees is:', g_no_of_employees.

ENDMETHOD.

ENDCLASS.

************************************************************************

* R E P O R T

*********************************************************************DATA: g_employee1 TYPE REF TO lcl_employee,

g_employee2 TYPE REF TO lcl_employee.

START-OF-SELECTION.

CREATE OBJECT g_employee1

EXPORTING im_employee_no = 1

im_employee_name = 'John Jones'.

CREATE OBJECT g_employee2

EXPORTING im_employee_no = 2

im_employee_name = 'Sally Summer'.

CALL METHOD g_employee1->display_employee.

CALL METHOD g_employee2->display_employee.

CALL METHOD g_employee2->display_no_of_employees.

2. Inheritance and polymorphismThis example uses a superclass lcl_company_employees and two subclasses lcl_bluecollar_employee and lcl_whitecollar_employee to add employees to a list and then display a list of employees and there wages. The wages are calculated in the method add_employee, but as the wages are calculated differently for blue collar employees and white collar employees, the superclass method add_employee is redefined in the subclasses.

Principles:Create super class LCL_CompanyEmployees.

The class has the methods:

Constructor

Add_Employee - Adds a new employee to the list of employees

Display_Employee_List - Displays all employees and there wage

Display_no_of_employees - Displays total number of employees

Note the use of CLASS-DATA to keep the list of employees and number of employees the same from instance to instance.

Create subclasses lcl_bluecollar_employee and lcl_whitecollar_employee. The classes are identical, except for the redefinition of the add_employee method, where the calculation of wage is different.

Methods:

Constructor. The constructor is used to initialize the attributes of the employee. Note that the constructor in the superclasss has to be called from within the constructor of the subclass.

Add_Employee. This is a redefinition of the same method in the superclass. In the redefined class the wage is calculated, and the superclass method is called to add the employees to the employee list:

The program

REPORT zbc404_hf_events_2 .

*******************************************************

* Super class LCL_CompanyEmployees

*******************************************************

CLASS lcl_company_employees DEFINITION. PUBLIC SECTION.

TYPES:


no TYPE i,

name TYPE string,

wage TYPE i,

END OF t_employee.

METHODS:

constructor,

add_employee

IMPORTING im_no TYPE i

im_name TYPE string

im_wage TYPE i,

display_employee_list,

display_no_of_employees.

PRIVATE SECTION.

CLASS-DATA: i_employee_list TYPE TABLE OF t_employee,

no_of_employees TYPE i.

ENDCLASS.*-- CLASS LCL_CompanyEmployees IMPLEMENTATIONCLASS lcl_company_employees IMPLEMENTATION. METHOD constructor.

no_of_employees = no_of_employees + 1.

ENDMETHOD.

METHOD add_employee.

* Adds a new employee to the list of employees DATA: l_employee TYPE t_employee.

l_employee-no = im_no.

l_employee-name = im_name.

l_employee-wage = im_wage.

APPEND l_employee TO i_employee_list.

ENDMETHOD.

METHOD display_employee_list.

* Displays all employees and there wage DATA: l_employee TYPE t_employee.

WRITE: / 'List of Employees'.

LOOP AT i_employee_list INTO l_employee.

WRITE: / l_employee-no, l_employee-name, l_employee-wage.

ENDLOOP.

ENDMETHOD.


* Displays total number of employees SKIP 3.

WRITE: / 'Total number of employees:', no_of_employees.

ENDMETHOD.

ENDCLASS.*******************************************************

* Sub class LCL_BlueCollar_Employee

*******************************************************

CLASS lcl_bluecollar_employee DEFINITION

INHERITING FROM lcl_company_employees. PUBLIC SECTION.

METHODS:

constructor


im_name TYPE string

im_hours TYPE i

im_hourly_payment TYPE i,

add_employee REDEFINITION.

PRIVATE SECTION.

DATA:no TYPE i,

name TYPE string,

hours TYPE i,

hourly_payment TYPE i.

ENDCLASS.*---- CLASS LCL_BlueCollar_Employee IMPLEMENTATIONCLASS lcl_bluecollar_employee IMPLEMENTATION. METHOD constructor.

* The superclass constructor method must be called from the subclass

* constructor method CALL METHOD super->constructor.

no = im_no.

name = im_name.

hours = im_hours.

hourly_payment = im_hourly_payment.

ENDMETHOD.


* Calculate wage and call the superclass method add_employee to add

* the employee to the employee list DATA: l_wage TYPE i.

l_wage = hours * hourly_payment.

CALL METHOD super->add_employee

EXPORTING im_no = no

im_name = name

im_wage = l_wage.

ENDMETHOD.

ENDCLASS.

*******************************************************

* Sub class LCL_WhiteCollar_Employee

*******************************************************CLASS lcl_whitecollar_employee DEFINITION


METHODS:

constructor


im_name TYPE string

im_monthly_salary TYPE i

im_monthly_deductions TYPE i,

add_employee REDEFINITION.

PRIVATE SECTION.

DATA:

no TYPE i,

name TYPE string,

monthly_salary TYPE i,

monthly_deductions TYPE i.

ENDCLASS.*---- CLASS LCL_WhiteCollar_Employee IMPLEMENTATIONCLASS lcl_whitecollar_employee IMPLEMENTATION. METHOD constructor.


* constructor method

CALL METHOD super->constructor.

no = im_no.

name = im_name.

monthly_salary = im_monthly_salary.

monthly_deductions = im_monthly_deductions.

ENDMETHOD.


* Calculate wage and call the superclass method add_employee to add


l_wage = monthly_salary - monthly_deductions.

CALL METHOD super->add_employee

EXPORTING im_no = no

im_name = name

im_wage = l_wage.

ENDMETHOD.

ENDCLASS.*******************************************************

* R E P O R T

*******************************************************DATA:

* Object references o_bluecollar_employee1 TYPE REF TO lcl_bluecollar_employee,

o_whitecollar_employee1 TYPE REF TO lcl_whitecollar_employee.

START-OF-SELECTION.

* Create bluecollar employee object CREATE OBJECT o_bluecollar_employee1

EXPORTING im_no = 1

im_name = 'Gylle Karen'

im_hours = 38

im_hourly_payment = 75.

* Add bluecollar employee to employee list CALL METHOD o_bluecollar_employee1->add_employee

EXPORTING im_no = 1


im_wage = 0.

* Create whitecollar employee object CREATE OBJECT o_whitecollar_employee1

EXPORTING im_no = 2

im_name = 'John Dickens'

im_monthly_salary = 10000

im_monthly_deductions = 2500.

* Add bluecollar employee to employee list CALL METHOD o_whitecollar_employee1->add_employee

EXPORTING im_no = 1

im_name = 'Karen Johnson'

im_wage = 0.

* Display employee list and number of employees. Note that the result

* will be the same when called from o_whitecollar_employee1 or

* o_bluecollar_employee1, because the methods are defined

* as static (CLASS-METHODS) CALL METHOD o_whitecollar_employee1->display_employee_list.

CALL METHOD o_whitecollar_employee1->display_no_of_employees.

The resulting reportList of Employees 1 Karen Johnson 2.850 2 John Dickens 7.500

Total number of employees: 2

3. InterfacesThis example is similar to the previous example, however an interface is implemented with the method add_employee. Note that the interface is only implemented in the superclass (The INTERFACE statement), but also used in the subclasses.

The interface in the example only contains a method, but an interface can also contain attributes, constants, types and alias names.

The output from example 3 is similar to the output in example 2.

All changes in the program compared to example 2 are marked with red.


*---------------------------------------------------------------------*

* INTERFACE lif_employee

*---------------------------------------------------------------------*

INTERFACE lif_employee.

METHODS:

add_employee


im_name TYPE string

im_wage TYPE i.

ENDINTERFACE.

*******************************************************


*******************************************************

CLASS lcl_company_employees DEFINITION. PUBLIC SECTION.

INTERFACES lif_employee.

TYPES:


no TYPE i,

name TYPE string,

wage TYPE i,

END OF t_employee.

METHODS:

constructor,

* add_employee "Removed IMPORTING im_no TYPE i

im_name TYPE string

im_wage TYPE i,


display_no_of_employees.

PRIVATE SECTION.

CLASS-DATA: i_employee_list TYPE TABLE OF t_employee,




ENDMETHOD.

METHOD lif_employee~add_employee.* Adds a new employee to the list of employees DATA: l_employee TYPE t_employee.





ENDMETHOD.






ENDLOOP.

ENDMETHOD.




ENDMETHOD.

ENDCLASS.*******************************************************


*******************************************************



METHODS:

constructor


im_name TYPE string

im_hours TYPE i

im_hourly_payment TYPE i,

lif_employee~add_employee REDEFINITION..

PRIVATE SECTION.

DATA:no TYPE i,

name TYPE string,

hours TYPE i,

hourly_payment TYPE i.

ENDCLASS.*---- CLASS LCL_BlueCollar_Employee IMPLEMENTATIONCLASS lcl_bluecollar_employee IMPLEMENTATION. METHOD constructor.


* constructor method CALL METHOD super->constructor.

no = im_no.

name = im_name.

hours = im_hours.

hourly_payment = im_hourly_payment.

ENDMETHOD.

METHOD lif_employee~add_employee.* Calculate wage and call the superclass method add_employee to add


l_wage = hours * hourly_payment.

CALL METHOD super->lif_employee~add_employee EXPORTING im_no = no

im_name = name

im_wage = l_wage.

ENDMETHOD.

ENDCLASS.

*******************************************************


*******************************************************CLASS lcl_whitecollar_employee DEFINITION


METHODS:

constructor


im_name TYPE string

im_monthly_salary TYPE i

im_monthly_deductions TYPE i,

lif_employee~add_employee REDEFINITION. PRIVATE SECTION.

DATA:

no TYPE i,

name TYPE string,

monthly_salary TYPE i,

monthly_deductions TYPE i.

ENDCLASS.*---- CLASS LCL_WhiteCollar_Employee IMPLEMENTATIONCLASS lcl_whitecollar_employee IMPLEMENTATION. METHOD constructor.


* constructor method

CALL METHOD super->constructor.

no = im_no.

name = im_name.

monthly_salary = im_monthly_salary.

monthly_deductions = im_monthly_deductions.

ENDMETHOD.

METHOD lif_employee~add_employee.* Calculate wage and call the superclass method add_employee to add


l_wage = monthly_salary - monthly_deductions.

CALL METHOD super->lif_employee~add_employee EXPORTING im_no = no

im_name = name

im_wage = l_wage.

ENDMETHOD.

ENDCLASS.*******************************************************

* R E P O R T

*******************************************************DATA:



START-OF-SELECTION.

* Create bluecollar employee obeject CREATE OBJECT o_bluecollar_employee1

EXPORTING im_no = 1


im_hours = 38


* Add bluecollar employee to employee list CALL METHOD o_bluecollar_employee1->lif_employee~add_employee EXPORTING im_no = 1


im_wage = 0.

* Create whitecollar employee obeject CREATE OBJECT o_whitecollar_employee1

EXPORTING im_no = 2




* Add bluecollar employee to employee list CALL METHOD o_whitecollar_employee1->lif_employee~add_employee EXPORTING im_no = 1


im_wage = 0.



* o_bluecolarcollar_employee1, because the methods are defined

* as static (CLASS-METHODS) CALL METHOD o_whitecollar_employee1->display_employee_list.


4. EventsThis is the same example as example 4. All changes are marked with red. There have been no changes to the subclasses, only to the superclass and the report, sp the code for the subclasses is not shown.

For a simple example refer to Events in Examples.


*---------------------------------------------------------------------*

* INTERFACE lif_employee

*---------------------------------------------------------------------*INTERFACE lif_employee.

METHODS:

add_employee


im_name TYPE string

im_wage TYPE i.

ENDINTERFACE.

*******************************************************


*******************************************************CLASS lcl_company_employees DEFINITION. PUBLIC SECTION.

TYPES:


no TYPE i,

name TYPE string,

wage TYPE i,

END OF t_employee.

* Declare event. Note that declaration could also be placed in the

* interface EVENTS: employee_added_to_list

EXPORTING value(ex_employee_name) TYPE string.

* CLASS-EVENTS: Events can also be defined as class-events INTERFACES lif_employee.

METHODS:

constructor,


display_no_of_employees,

* Declare event method

on_employee_added_to_list FOR EVENT employee_added_to_list OF lcl_company_employees

IMPORTING ex_employee_name sender. PRIVATE SECTION.

CLASS-DATA:

i_employee_list TYPE TABLE OF t_employee,




ENDMETHOD.

METHOD lif_employee~add_employee.

* Adds a new employee to the list of employees

DATA: l_employee TYPE t_employee.





* Raise event employee_added_to_list RAISE EVENT employee_added_to_list

EXPORTING ex_employee_name = l_employee-name. ENDMETHOD.






ENDLOOP.

ENDMETHOD.




ENDMETHOD.

METHOD on_employee_added_to_list.

* Event method WRITE: / 'Employee added to list', ex_employee_name.

ENDMETHOD.ENDCLASS.*******************************************************


*******************************************************


INHERITING FROM lcl_company_employees.

See code in example 3...ENDCLASS.CLASS lcl_bluecollar_employee IMPLEMENTATION. See code in example 3...ENDCLASS.*******************************************************


*******************************************************

CLASS lcl_whitecollar_employee DEFINITION See code in example 3...ENDCLASS.CLASS lcl_whitecollar_employee IMPLEMENTATION. See code in example 3...ENDCLASS.*******************************************************

* R E P O R T

*******************************************************DATA:



START-OF-SELECTION.

* Create bluecollar employee obeject CREATE OBJECT o_bluecollar_employee1

EXPORTING im_no = 1


im_hours = 38


* Register event for o_bluecollar_employee1 SET HANDLER o_bluecollar_employee1->on_employee_added_to_list

FOR o_bluecollar_employee1.

* Add bluecollar employee to employee list CALL METHOD o_bluecollar_employee1->lif_employee~add_employee

EXPORTING im_no = 1


im_wage = 0.

* Create whitecollar employee object CREATE OBJECT o_whitecollar_employee1

EXPORTING im_no = 2




* Register event for o_whitecollar_employee1 SET HANDLER o_whitecollar_employee1->on_employee_added_to_list

FOR o_whitecollar_employee1.

* Add bluecollar employee to employee list CALL METHOD o_whitecollar_employee1->lif_employee~add_employee

EXPORTING im_no = 1


im_wage = 0.



* o_bluecolarcollar_employee1, because the methods are defined

* as static (CLASS-METHODS)

CALL METHOD o_whitecollar_employee1->display_employee_list.


Result:

Employee added to list Karen Johnson Employee added to list John Dickens List of Employees 1 Karen Johnson 2.850 2 John Dickens 7.500

Total number of employees: 2

GeneralControl Framework and inheritance hierarchyThe control framework consists of 2 parts:

CL_GUI_CFW contains methods that provide services for communication with the frontend, and can be used both by control wrapper classes and by control programmers

The CL_GUI_OBJECT encapsulates ActiveX or JavaBeans methods, while CL_GUI_CONTROL is responsible for displaying the control on the screen.

CL_GUI_OBJECT -> CL_GUI_CONTROL -> CL_GUI_* (Wrapper class)

These classes contains methods that are inherited by subsequent classes in the inheritance tree.

Synchronization/FlushRFC calls is used to synchronize the front and backend. This synchronization takes place at some predefined points in the program flow. However you should not rely entirely on automatic synchronization, but force synchronization with the Flush method when necessary.

Bear in mind that the synchronization/RFC calls represents a bottleneck, so you should keep the not use the Flush method to a minimum.

Syntax:

CALL METHOD cl_gui_cfw=>FLUSH

Set up event handling for controlsThere are two types of events:

Application events. TThe flow logic of the screen is processed after the event (The PAI module is processed).

In the events table the event must be registered as an application event by setting the field appl_event to 'X':

wa_events-eventid = cl_gui_textedit=>event_double_click.wa_events-appl_event = 'X'. append wa_events to i_events.

Important: The dispatch method of cl_gui_cfw must be called in the PAI module:

CALL METHOD cl_gui_cfw=>dispatch.

System events. For system events the flow-logic of the screen is not executed. That means that the PAI and PBO modules are not processed.

In the events table the field appl_event must be set to SPACE:

wa_events-eventid = cl_gui_textedit=>event_double_click.wa_events-appl_event = space. append wa_events to i_events.

The dispatch method of cl_gui_cfw must NOT be called.

ExampleIt is presumed that a SAP toolbar control named go_toolbar of class cl_gui_toolbar has been defined. To see a complete example of how to handle events, refer to The SAP toolbar control.

Data:

* 1. Define the instance of the eventhandler class.

* If the event handler class is defined after the data declaration

* the class must be declared as DEFERRED in the top of the program: CLASS cls_event_handler DEFINITION DEFERRED.

go_event_handler TYPE REF TO cls_event_handler,* 2. Define table for registration of events. * Note that a TYPE REF to cls_event_handler must be created before you can

* reference types cntl_simple_events and cntl_simple_event

gi_events TYPE cntl_simple_events,

* Workspace for table gi_events g_event TYPE cntl_simple_event.* 3. Define and implement eventhandler classCLASS cls_event_handler DEFINITION.

PUBLIC SECTION.

METHODS:

* Syntax:

* FOR EVENT

* OF

on_function_selected

FOR EVENT function_selected OF cl_gui_toolbar

IMPORTING fcode,

ENDCLASS.CLASS cls_event_handler IMPLEMENTATION.

METHOD on_function_selected.

* Do something when the event is raised ENDMETHOD.

ENDCLASS.* 4. Append events to the events table* The Event Id can be found in the control documentation. Note that the event below is registered as an application event

g_event-eventid = go_toolbar->m_id_function_selected.

g_event-appl_event = 'X'. "This is an application event

APPEND g_event TO gi_events.

.... append more events i necessary...* 5. Use the events table to register events for the control CALL METHOD go_toolbar->set_registered_events

EXPORTING

events = gi_events.* 6. Create event handlerCREATE OBJECT go_event_handler.* Syntax:

* SET HANDLER ->

* FOR SET HANDLER go_event_handler->on_function_selected

FOR go_toolbar.

Declare a reference variable before the class has been definedScenario:

DATA: o_my_class TYPE REF TO lcl_myclass.

CLASS lcl_myclass.....ENDCLASS.

This will cause an error because the definition of class lcl_myclass is after the declaration.

Solution:

Define the class in the beginning of the program with DEFINITION DEFERRED:

CLASS lcl_myclass DEFINITION DEFERRED.

DATA: o_my_class TYPE REF TO lcl_myclass.

CLASS lcl_myclass.....ENDCLASS.

Set focus to a controlSet the focus to a control named go_grid:

CALL METHOD cl_gui_control=>set_focus

EXPORTING control = go_grid.To Use BADI - Business Add In you need to Understand ABAP OO Interface Concept

Content Author: Jayanta Narayan Choudhuri Author Email: [email protected] Author Website: http://www.geocities.com/ojnc

* For Rajat's OO ans BAdI Education

Report Z_CTRY.

* A Shape Interface "Like a shape" "Behaves like a Shape"

Adverb/Adjective

Interface IShape.

Methods: getArea Returning Value(area) Type F,

getCircumference Returning Value(circumference) Type F.

Endinterface.

* A Circle Class that behaves like a Shape

Class CCircle Definition.

Public Section.

Interfaces IShape.

Aliases: getArea For IShape~getArea,

getCircumference For IShape~getCircumference.

Methods: Constructor Importing pRadius Type F,

setRadius Importing pRadius Type F,

getRadius Returning Value(pRadius) Type F.

Private Section.

Data radius Type F.

Constants PI Type F Value '3.141592365359'.

EndClass.

Class CCircle Implementation.

Method Constructor.

radius = pRadius.

EndMethod.

Method setRadius.

radius = pRadius.

EndMethod.

Method getRadius.

pRadius = radius.

EndMethod.

Method IShape~getArea.

Compute area = 2 * PI * radius.

EndMethod.

Method IShape~getCircumference.

Compute circumference = PI * radius * radius.

EndMethod.

EndClass.

* A Square Class

Class CSquare Definition.

Public Section.

Interfaces IShape.



Methods: Constructor Importing pSide Type F.

Private Section.

Data side Type F.

EndClass.

Class CSquare Implementation.

Method Constructor.

side = pSide.

EndMethod.


Compute area = side * side.

EndMethod.


Compute circumference = 4 * side.

EndMethod.

EndClass.

* A Rectangle Class

Class CRectangle Definition.

Public Section.

Interfaces IShape.



Methods: Constructor Importing pHeight Type F

pLength Type F.

Private Section.

Data: height Type F,

length Type F.

EndClass.

Class CRectangle Implementation.

Method Constructor.

height = pHeight.

length = pLength.

EndMethod.


Compute area = height * length.

EndMethod.


Compute circumference = 2 * ( height + length ).

EndMethod.

EndClass.

* START of PROGRAM

* Array of Shapes

Data: OneShape Type Ref To IShape, " One Object with

Shape Behaviour

ShapeTable Type Table Of Ref To IShape. " Array of Objects

with Shape Behaviour

* Concrete Objects with IShape Behaviour!

Data: C1 Type Ref To CCircle,

S1 Type Ref To CSquare,

R1 Type Ref To CRectangle,

C2 Type Ref To CCircle,

S2 Type Ref To CSquare,

R2 Type Ref To CRectangle.

Data: descr_ref TYPE ref to CL_ABAP_TYPEDESCR,

ClassName Type String,

Serial Type I.

Data: myArea Type F,

myCircumference Type F.

START-OF-SELECTION.

Create Object C1 Exporting pRadius = '2.5'.

Create Object C2 Exporting pRadius = '5.0'.

Create Object S1 Exporting pSide = '3.5'.

Create Object S2 Exporting pSide = '6.0'.

Create Object R1 Exporting pHeight = '2.8' pLength = '3.4'.

Create Object R2 Exporting pHeight = '1.7' pLength = '6.3'.

* Append in any order!

Append S1 to ShapeTable.

Append R2 to ShapeTable.

Append R1 to ShapeTable.

Append C2 to ShapeTable.

Append C1 to ShapeTable.

Append S2 to ShapeTable.

Serial = 0.

Loop At ShapeTable into OneShape.

Call Method OneShape->getArea

Receiving area = myArea.

Call Method OneShape->getCircumference

Receiving circumference = myCircumference.

descr_ref = CL_ABAP_TYPEDESCR=>Describe_By_Object_Ref( OneShape

).

Call Method descr_ref->get_relative_name

Receiving P_RELATIVE_NAME = ClassName.

Add 1 to Serial.

Write: / Serial, ClassName.

Write: / 'Area ', myArea Decimals 4 Exponent

0.

Write: / 'Circumference ', myCircumference Decimals 4 Exponent

0.

Write: /.

EndLoop.

** Results

* 1 CSQUARE

* Area 12.2500

* Circumference 14.0000

*

* 2 CRECTANGLE

* Area 10.7100


*

* 3 CRECTANGLE

* Area 9.5200


*

* 4 CCIRCLE

* Area 31.4159


*

* 5 CCIRCLE

* Area 15.7080


*

* 6 CSQUARE

* Area 36.0000


Example 1: Creating the TextEdit controlThis is a simple example of how to implement a text edit control.

Steps1. Create a report

2. In the start of selection event add: SET SCREEN '100'.

3. Create screen 100

4. Place a custom control on the screen by choosing the custom control icon which can be recognized by the letter 'C', and give it the name MYCONTAINER1.

5. To be able to exit the program, add a pushbutton with the function code EXIT.

6. In the elements list enter the name OK_CODE for the element of type OK.

The codeREPORT sapmz_hf_controls1 .CONSTANTS:

line_length TYPE i VALUE 254.

DATA: ok_code LIKE sy-ucomm.

DATA:

* Create reference to the custom container custom_container TYPE REF TO cl_gui_custom_container,

* Create reference to the TextEdit control editor TYPE REF TO cl_gui_textedit,

repid LIKE sy-repid.

START-OF-SELECTION.

SET SCREEN '100'.

*---------------------------------------------------------------------*

* MODULE USER_COMMAND_0100 INPUT *

*---------------------------------------------------------------------*

MODULE user_command_0100 INPUT.

CASE ok_code.

WHEN 'EXIT'.

LEAVE TO SCREEN 0.

ENDCASE.

ENDMODULE. " USER_COMMAND_0100 INPUT

*&---------------------------------------------------------------------*

*& Module STATUS_0100 OUTPUT

*&---------------------------------------------------------------------*

MODULE status_0100 OUTPUT.

* The TextEdit control shoul only be initialized the first time the

* PBO module executes

IF editor IS INITIAL.

repid = sy-repid.

* Create obejct for custom container CREATE OBJECT custom_container

EXPORTING

container_name = 'MYCONTAINER1'

EXCEPTIONS

cntl_error = 1

cntl_system_error = 2

create_error = 3

lifetime_error = 4

lifetime_dynpro_dynpro_link = 5

others = 6

.

IF sy-subrc 0.

MESSAGE ID sy-msgid TYPE 'I' NUMBER sy-msgno

WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.

ENDIF.

* Create obejct for the TextEditor control CREATE OBJECT editor

EXPORTING

wordwrap_mode =

cl_gui_textedit=>wordwrap_at_fixed_position

wordwrap_position = line_length

wordwrap_to_linebreak_mode = cl_gui_textedit=>true

parent = custom_container

EXCEPTIONS

error_cntl_create = 1

error_cntl_init = 2

error_cntl_link = 3

error_dp_create = 4

gui_type_not_supported = 5

others = 6

.

IF sy-subrc 0.



ENDIF.

ENDIF.

ENDMODULE. " STATUS_0100 OUTPUT

The result

Example 2: Event handling - Application eventThere are 2 types of events:

System events. These events are triggerede irrespective of the screen flow-logic.

Application events. The PAI module is processed after an event. The method CL_GUI_CFW=>DISPATCH must be called to initiate event handling

In this example an application event is added to the program in example 1. New code is marked with red.

Steps:

1. Create an input/output field on screen 100, where the event type can be output. Name it EVENT_TYPE

The code:

REPORT sapmz_hf_controls1 .CONSTANTS:



DATA:




**********************************************************************

* Impmenting events

**********************************************************************DATA:

event_type(20) TYPE c,

* Internal table for events that should be registred

i_events TYPE cntl_simple_events,

* Structure for oneline of the table

wa_events TYPE cntl_simple_event.*---------------------------------------------------------------------*

* CLASS lcl_event_handler DEFINITION

*---------------------------------------------------------------------*

CLASS lcl_event_handler DEFINITION.

PUBLIC SECTION.

CLASS-METHODS:

catch_dblclick FOR EVENT dblclick

OF cl_gui_textedit IMPORTING sender.ENDCLASS.CLASS lcl_event_handler IMPLEMENTATION.

METHOD catch_dblclick.

event_type = 'Event DBLCLICK raised'.

ENDMETHOD.

ENDCLASS.

START-OF-SELECTION.

CLEAR wa_events. refresh i_events.

SET SCREEN '100'.

*---------------------------------------------------------------------*


*---------------------------------------------------------------------*


CASE ok_code.

WHEN 'EXIT'.

LEAVE TO SCREEN 0.

WHEN OTHERS.

* Call the Dispacth method to initiate application event handling call method cl_gui_cfw=>Dispatch. ENDCASE.


*&---------------------------------------------------------------------*


*&---------------------------------------------------------------------*



* PBO module executes IF editor IS INITIAL.

repid = sy-repid.

* Create obejct for custom container CREATE OBJECT custom_container

EXPORTING


EXCEPTIONS

cntl_error = 1


create_error = 3

lifetime_error = 4


others = 6

.

IF sy-subrc 0.



ENDIF.


EXPORTING

wordwrap_mode =





EXCEPTIONS


error_cntl_init = 2

error_cntl_link = 3

error_dp_create = 4


others = 6

.

IF sy-subrc 0.



ENDIF.

* Link the event handler method to the event and the

* TextEdit control SET HANDLER lcl_event_handler=>catch_dblclick FOR editor.* Register the event in the internal table i_events wa_events-eventid = cl_gui_textedit=>event_double_click.

wa_events-appl_event = 'X'. "This is an application event

append wa_events to i_events.* Pass the table to the TextEdit control using method

* set_registred_events

call method editor->set_registered_events

exporting events = i_events. ENDIF.


Result:When you double click on the TextEdit control, the input/ouput field should show the text: Event DBLCLICKExample 3: Event handling - System eventSystem events are passed irrespective of the flow-logic of the screen. To implement a system event change the code from example 2 as follows:

Code:CLASS lcl_event_handler IMPLEMENTATION.


*--- event_type = 'Event DBLCLICK raised'.* Reacting to the system event call method cl_gui_cfw=>set_new_ok_code

exporting new_code = 'SHOW'.


CASE ok_code.

code.........

WHEN 'SHOW'.

event_type = 'System dblclick'. WHEN OTHERS.

*---- call method cl_gui_cfw=>Dispatch. ENDCASE.



Code ................

*--- wa_events-appl_event = 'X'. "This is an application event

wa_events-appl_event = space. "This is a system event

ENDIF.


Result:When you double clicks on the TextEdit control nothing happens, since the flow-logic of the screen an dthe fielde transport is ignore.

Example 4: Calling methods of the controlIn this exercise a function that loads the texts of an internal table into the text window, is implemented.

Steps:Define anoterh pushbutton on the screen, that activates the method that fills the TextEdit control. Give itname PUSHBUTTON_IMPORT and function code IMP.

Define a form CREATE_TEXTS that carries out the text import.

Only changes to the code in example 2 is show.

Code:MODULE user_command_0100 INPUT. CASE ok_code.

code.........

WHEN 'IMP'.

perform load_texts. ENDCASE.

ENDMODULE. " USER_COMMAND_0100 INPUT*&---------------------------------------------------------------------*

*& Form load_texts

*&---------------------------------------------------------------------*

* This form creates an internal table with texts. The the contents of

* the table is instered into the TextEdit control using method

* set_text_as_r3table

*----------------------------------------------------------------------*FORM load_texts.

TYPES:

BEGIN OF t_texttable,

line(line_length) TYPE c,

END OF t_texttable.

DATA

i_texttable TYPE TABLE OF t_texttable.

* Create internal table with texts APPEND 'This a method that fills the TextEdit control' TO i_texttable.

APPEND 'with a text.' TO i_texttable.

DO 10 TIMES.

APPEND 'hallo world !' TO i_texttable.

ENDDO.

* Load TextEdit control with texts CALL METHOD editor->set_text_as_r3table

EXPORTING table = i_texttable.

IF sy-subrc > 0.

* Display an error message

EXIT.

ENDIF.

* All methods that operates on controls are transferred to the frontend

* by a RFC calls. the method FLUSH is used to determine when this is done. CALL METHOD cl_gui_cfw=>flush.

IF sy-subrc > 0.

* Display an error message

ENDIF.

ENDFORM. " create_texts

Example 5: Responding to an eventWhen you double click on a text line in the TextEdit control, you want it to be prefixed with a '*'.

The line number of the TextEdit control that is double clicked, is retreived using method GET_SELECTION_POS. The internal text table is reloaded froim the TextEdit control with method GET_TEXT_AS_R3TABLE. The position of the double click in the TextEdit control is used to find the entry in the table, and the entry is prefixed with '*' and loaded into the TextEdit control again.

The program should be changed so that the internal table i_texttable is global, and a global flag g_loaded added. The load of the table should be moved to the PBO module. The changes in thje code are marked with red. The whole program now looks like this:

CodeREPORT sapmz_hf_controls1 .CONSTANTS:



DATA:




**********************************************************************

* Utillity table to load texts

**********************************************************************TYPES:

BEGIN OF t_texttable,

line(line_length) TYPE c,

END OF t_texttable.DATA:

i_texttable TYPE TABLE OF t_texttable,

g_loaded(1) TYPE c.**********************************************************************

* Impmenting events

**********************************************************************DATA:

event_type(20) TYPE c,

* Internal table for events that should be registred i_events TYPE cntl_simple_events,

* Structure for oneline of the table wa_events TYPE cntl_simple_event.

*---------------------------------------------------------------------*

* CLASS lcl_event_handler DEFINITION

*---------------------------------------------------------------------*CLASS lcl_event_handler DEFINITION.

PUBLIC SECTION.

CLASS-METHODS:

catch_dblclick FOR EVENT dblclick

OF cl_gui_textedit IMPORTING sender.

ENDCLASS.

CLASS lcl_event_handler IMPLEMENTATION.


DATA:

from_line TYPE i,

from_pos TYPE i,

to_line TYPE i,

to_pos TYPE i,

wa_texttable TYPE t_texttable.

* Used for the sytem event call method cl_gui_cfw=>set_new_ok_code

exporting new_code = 'SHOW'.

* Read the position of the double click CALL METHOD sender->get_selection_pos

IMPORTING

from_line = from_line

from_pos = from_pos

to_line = to_line

to_pos = to_pos.* Texts in the TextEdit control can have been changed, so

* first reload text from the control into the internal

* table that contains text IF NOT g_loaded IS INITIAL.

CALL METHOD sender->get_text_as_r3table

IMPORTING table = i_texttable.

* Read the line of the internal table that was clicked READ TABLE i_texttable INDEX from_line INTO wa_texttable.

IF sy-subrc 0.

EXIT.

ENDIF. IF wa_texttable+0(1) CS '*'.

SHIFT wa_texttable.

ELSEIF wa_texttable+0(1) NS '*'.

SHIFT wa_texttable RIGHT.

wa_texttable+0(1) = '*'.

ENDIF.

modify i_texttable from wa_texttable index from_line.* Reload texts from h einternal table perform load_texts. ENDIF.

ENDMETHOD.

ENDCLASS.

START-OF-SELECTION.

CLEAR wa_events.

REFRESH: i_events.

SET SCREEN '100'.

*---------------------------------------------------------------------*


*---------------------------------------------------------------------*MODULE user_command_0100 INPUT.

CASE ok_code.

WHEN 'EXIT'.

LEAVE TO SCREEN 0.

WHEN 'SHOW'.

event_type = 'System dblclick'.

WHEN 'IMP'.

PERFORM Load_texts.

WHEN OTHERS.

* CALL METHOD cl_gui_cfw=>dispatch. "Not used for system events

ENDCASE.


*&---------------------------------------------------------------------*


*&---------------------------------------------------------------------*MODULE status_0100 OUTPUT.


* PBO module executes IF editor IS INITIAL.

repid = sy-repid.

* Create object for custom container CREATE OBJECT custom_container

EXPORTING


EXCEPTIONS

cntl_error = 1


create_error = 3

lifetime_error = 4


others = 6

.

IF sy-subrc 0.



ENDIF.


EXPORTING

wordwrap_mode =





EXCEPTIONS


error_cntl_init = 2

error_cntl_link = 3

error_dp_create = 4


others = 6

.

IF sy-subrc 0.



ENDIF.

* Link the event handler method to the event and the

* TextEdit control SET HANDLER lcl_event_handler=>catch_dblclick FOR editor.

* Register the event in the internal table i_events wa_events-eventid = cl_gui_textedit=>event_double_click.

* wa_events-appl_event = 'X'. "This is an application event wa_events-appl_event = space. "This is a system event

APPEND wa_events TO i_events.

* Pass the table to the TextEdit control uding method

* set_registred_events CALL METHOD editor->set_registered_events

EXPORTING events = i_events.

* Create internal table with texts taht can be uploaded to

* the TextEdit control APPEND 'This a method that fills the TextEdit control' TO i_texttable.

APPEND 'with a text.' TO i_texttable.

DO 10 TIMES.

APPEND 'hallo world !' TO i_texttable.

ENDDO.

ENDIF.


*&---------------------------------------------------------------------*

*& Form Load_texts

*&---------------------------------------------------------------------*

* This form loads the lines of the internal table i_texttable into

* the TextEdit control

*----------------------------------------------------------------------*FORM Load_texts.

* Load TextEdit control with texts CALL METHOD editor->set_text_as_r3table

EXPORTING table = i_texttable.

IF sy-subrc > 0.

* Display an error message EXIT.

ENDIF.

* All methods that operates on controls are transferred to the frontend

* by a RFC calls. the method FLUSH is used to determine when this is

* done. CALL METHOD cl_gui_cfw=>flush.

IF sy-subrc > 0.

* Display an error message ENDIF.

g_loaded = 'X'.

ENDFORM. " create_texts

Example 6: Protect a line in the TextEdit control and the importance of FLUSH

All methods that operates on controls are transfered to the fronend by RFC calls. The FLUSH method is used to synchronize control execution and the frontend. This is very important when working e.g. with export parameters from a method, as the parmeters will not be correct before the FLUSH method has been called.

The example below portects selected lines in the TextEdit and uses FLUSH to ensure that the correct parameters are returned from method GET_SELECTION_POS.

Note: Instead of using method PROTECT_LINES, the method PROTECT_SELECTION could be used. This method does not need line numbers or a FLUSH statement

Steps Add a new pushbutton to the screen with the function code PROTECT.

CodeAdd the following code to the example:

* Global variablesDATA:

from_idx TYPE i,

to_idx TYPE i,

index TYPE i.


CASE ok_code.

code.......................

WHEN 'PROTECT'.

PERFORM protect.

. .......................

ENDCASE.

*&---------------------------------------------------------------------*

*& Form protect

*&---------------------------------------------------------------------*

* Protects marked lines in a TextEdit control

*----------------------------------------------------------------------*FORM protect.

* Determine the area selected by the user CALL METHOD editor->get_selection_pos

IMPORTING

from_line = from_idx

to_line = to_idx

EXCEPTIONS

error_cntl_call_method = 1.

* Synchronize execution in the control with the ABAP program.

* Without this synchronization the variables from_idx and

* to_idx will have obsolutete values (The initial value for

* both, are 0) CALL METHOD cl_gui_cfw=>flush.

IF sy-subrc > 0.

* Errormessage: Error in flush ENDIF.

* Protect the selected lines IF to_idx > from_idx.

to_idx = to_idx - 1.

ENDIF.

CALL METHOD editor->protect_lines

EXPORTING

from_line = from_idx

to_line = to_idx.

* The PROTECT_SELECTION method could be used instead, eliminating the

* need of line numbers and the last FLUSH

* call method editor->protect_selection.* Flush again to protect immidiately

CALL METHOD cl_gui_cfw=>flush.

IF sy-subrc > 0.

* Errormessage: Error in flush ENDIF.

ENDFORM. " protect

Example 7: Using multiple controlsIn this example a second TextEdit control will be added to the screen. The new TextEdit control will be designed to act as a clipboard for short texts.

Steps:

Add a new container to the screen and name it MYCONTAINER2.

Code:Insert global datadeclaration:

**********************************************************************

* Implementing a second Scratch TextEdit control

**********************************************************************

DATA:

scratch TYPE REF TO cl_gui_textedit,

custom_container2 TYPE REF TO cl_gui_custom_container.

Insert the following code in the PBO module:

*------------------------------------------------------

* The SCRATCH TextEdit control

*------------------------------------------------------

IF scratch IS INITIAL.

* Create obejct for custom container2 CREATE OBJECT custom_container2

EXPORTING


EXCEPTIONS

cntl_error = 1


create_error = 3

lifetime_error = 4


others = 6

.

IF sy-subrc 0.



ENDIF.

* Create obejct for the SCRATCH TextEditor control CREATE OBJECT scratch

EXPORTING

parent = custom_container2

wordwrap_mode =

cl_gui_textedit=>wordwrap_at_windowborder

wordwrap_to_linebreak_mode = cl_gui_textedit=>true.

* Remove the staus bar CALL METHOD scratch->set_statusbar_mode

EXPORTING statusbar_mode = cl_gui_textedit=>false.

ENDIF.

Result:

1 REPORT sapmz_hf_controls1 .

2

3 CONSTANTS:

4 line_length TYPE i VALUE 254.

5

6 DATA: ok_code LIKE sy-ucomm.

7

8 DATA:

9 * Create reference to the custom container 10 custom_container TYPE REF TO cl_gui_custom_container,

11 * Create reference to the TextEdit control 12 editor TYPE REF TO cl_gui_textedit,

13 repid LIKE sy-repid.

14

15 ********************************************************************** 16 * Utillity table to load texts 17 ********************************************************************** 18 TYPES:

19 BEGIN OF t_texttable,

20 line(line_length) TYPE c,

21 END OF t_texttable.

22

23 DATA:

24 i_texttable TYPE TABLE OF t_texttable,

25 wa_texttable TYPE t_texttable,

26 g_loaded(1) TYPE c.

27

28 ********************************************************************** 29 * Data for the protection example 30 ********************************************************************** 31 DATA:

32 from_idx TYPE i,

33 to_idx TYPE i,

34 index TYPE i.

35

36 ********************************************************************** 37 * Implementing a second Scratch TextEdit control 38 ********************************************************************** 39 DATA:

40 scratch TYPE REF TO cl_gui_textedit,

41 custom_container2 TYPE REF TO cl_gui_custom_container.

42

43

44 ********************************************************************** 45 * Implementing events 46 ********************************************************************** 47 DATA:

48 event_type(20) TYPE c,

49 * Internal table for events that should be registred 50 i_events TYPE cntl_simple_events,

51 * Structure for onelin

Documents

Oop concepts in ABAP